,*黑龙江八一农垦大学农学院, 黑龙江大庆 163319Effects of exogenous melatonin on physiology and yield of soybean during seed filling stage under drought stress
ZOU Jing-Nan, YU Qi, JIN Xi-Jun, WANG Ming-Yao, QIN Bin, REN Chun-Yuan, WANG Meng-Xue, ZHANG Yu-Xian,*College of Agronomy, Heilongjiang Bayi Agricultural University, Daqing 163319, Heilongjiang, China通讯作者:
收稿日期:2019-08-1接受日期:2019-12-26网络出版日期:2020-01-14
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Received:2019-08-1Accepted:2019-12-26Online:2020-01-14
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E-mail:zoujingnan222@163.com。
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邹京南, 于奇, 金喜军, 王明瑶, 秦彬, 任春元, 王孟雪, 张玉先. 外源褪黑素对干旱胁迫下大豆鼓粒期生理和产量的影响[J]. 作物学报, 2020, 46(5): 745-758. doi:10.3724/SP.J.1006.2020.94111
ZOU Jing-Nan, YU Qi, JIN Xi-Jun, WANG Ming-Yao, QIN Bin, REN Chun-Yuan, WANG Meng-Xue, ZHANG Yu-Xian.
大豆是我国重要的油料作物, 因干旱导致产量损失达25%~50%[1], 2018年8月辽宁沈阳和吉林公主岭地区遭遇因高温少雨引起的大面积干旱, 产量较2017年减少三成。大豆对干旱胁迫的最敏感时期是在开花期后[2], 鼓粒期是大豆子粒发育和产量形成的关键时期, 也是碳氮同化和转移生理代谢最复杂阶段, 随着鼓粒期进程, 大豆植株生理活性由旺盛逐渐变弱, 直至成熟。在此过程中, 不仅新同化的光合产物向子粒运输, 储存在营养器官中的同化物也由源(营养器官)向库(子粒)转移[3], 此阶段发生干旱胁迫势必对同化产物的形成和转运产生不利影响, 导致产量降低[4]。干旱胁迫还会降低大豆叶片光合能力, 导致电子传输链过度还原, 导致光氧化[5], 产生ROS [6]。ROS过度积累会损伤膜系统, 引起蛋白质降解、DNA损伤。植物自身通过调节抗氧化系统来应对氧化损伤, 如提高抗氧化酶活性和抗氧化剂含量, 同时通过提高诸如蔗糖等一些代谢酶活性, 增加可溶性糖、可溶性蛋白、脯氨酸含量等来减少细胞水分流失以及维持细胞膜结构稳定性[7,8,9,10]。这在短期或轻度干旱胁迫下能维持蔗糖含量为植物生长发育提供能量, 但氮同化能力会显著下降, 抑制蛋白质合成及光合产物的转运能力, 若干旱胁迫时间延长, 子粒则会停止生长甚至植株死亡[11,12]。
施植物生长调节剂是增强作物抗旱性的重要手段之一[13]。褪黑素(melatonin)在植物抵御非生物胁迫中发挥着重要保护作用[14]。近年来, 褪黑素在植物抗旱方面的研究取得了一定进展。外源褪黑素处理可提高干旱胁迫下玉米幼苗抗氧化酶活性[15]; 缓解干旱胁迫对光合系统的损伤[16]; 降低干旱胁迫下小麦中MDA、ROS含量, 提高谷胱甘肽ASA和GSH含量[17,18], 促进番茄ASA-GSH循环中APX和GR等活性的增加[19], 减缓干旱胁迫造成的氧化损伤。另外, 褪黑素处理可促进干旱胁迫下大豆叶片脯氨酸、可溶性糖和可溶性蛋白含量增加并增加产量[20]。
大豆是共生固氮作物, 对碳氮代谢能力要求较高, 而关于外源褪黑素对干旱胁迫条件下大豆碳氮代谢相关方面的研究未见报道。因此, 本试验研究外源褪黑素在干旱胁迫条件下对大豆鼓粒期生理变化的影响, 以及对产量损失缓解程度, 以期为其实际应用提供一定研究基础和理论指导。
1 材料与方法
1.1 试验材料和设计
大豆品种绥农26号, 由国家杂粮工程技术研究中心提供。褪黑素(meltaionin)购自Sigma试剂公司。以预备试验确定处理浓度为100 μmol L-1。试验于2017—2018年在黑龙江八一农垦大学国家杂粮工程技术研究中心试验基地进行, 将大豆种子用5%次氯酸钠(w:v)消毒3 min并用蒸馏水洗净, 在发芽盒22℃暗发芽1 d。挑选芽长约1 cm幼芽用于盆栽, 每盆3株。
盆栽所用白色塑料桶高0.33 m, 直径0.3 m, 桶底均钻3个1 cm直径小孔。在桶底铺一层纱网。培养土按珍珠岩︰蛭石︰黑钙土1:3:12 (v︰v︰v)的比例混合, 每桶装16 kg; 培养土2017年含碱解氮96.3 mg kg-1、速效磷 22.7 mg kg-1、速效钾69.7 mg kg-1、有机质11.5 mg kg-1, pH 7.8, 田间持水量46.1%; 2018年含碱解氮72.1 mg kg-1、速效磷14.1 mg kg-1、速效钾173.0 mg kg-1、有机质3.9 mg kg-1, pH 7.1, 田间持水量50%。
维持80%田间持水量至大豆生长至鼓粒初期(R5期, 倒数第4个豆荚籽粒约3 mm), 设置旱胁迫处理(D)、干旱胁迫下喷施褪黑素处理(MT+D)、正常供水对照(WW) 3个处理, 每个处理30盆。①干旱胁迫处理(D)在大豆生长至鼓粒期开始停止供水, 通过称重法控制土壤含水量(开始控水当天记为第1天, 每晚8时叶片喷施清水连续喷施5 d), 使土壤含水量逐渐达到田间持水量的50%取第1次样(2017年停止供水10 d达到50%田间持水量; 2018年停止供水8 d达到50%田间持水量, 维持此含水量到达处理第10天取第1次样), 之后维持50%田间持水量在处理第17天和第24天分别做第2次和第3次取样, ②干旱胁迫下喷施褪黑素处理(MT+D)在停止供水当天叶片喷施100 μmol L-1褪黑素溶液连续喷施5 d, 控水标准、复水时间和取样与D处理一致, 之后恢复正常供水成熟期测产。③土壤含水量始终保持田间持水量80%作为正常供水对照(WW); 处理第1天开始叶面喷施清水, 连续喷施5 d, 取样同D和MT+D。
1.2 测定项目和方法
1.2.1 大豆叶片光合特性参数、叶绿素荧光参数和Rubisco酶活性测定 光合特性参数使用(Li-6400; Li-Cor, Huntington Beach, CA, USA)光合仪测定大豆叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、胞间CO2浓度(Ci), 水分利用率(WUE) = Pn/Tr。测定光强为1200 μmol m-2 s-1, CO2供应浓度为400 μmol mol-1, 叶片温度25℃, 相对湿度约为25%; 使用叶绿素荧光仪(FMS-2, Hansatech, England)测量叶绿素荧光参数, 即大豆倒数第2片功能叶PSII的最大光化学效Fv/Fm, PSII的量子产额(ΦPSII), 光化学猝灭系数(qN)非光化学猝灭系数(NPQ), 最大光能转化潜力(Fv/Fo), 表观光合电子传递速率(ETR)。将冷冻的叶片在液氮中研磨成匀浆, 用2 mL含有50 mmol L-1 BICINE,N,N-二羟乙基甘氨酸、pH 8.0的20 mmol L-1 MgCl2、2 mmol L-1苯基甲磺酰氟、50 mmol L-1 2-巯基乙醇和30 mg聚乙烯基聚吡咯烷酮(PVPP)的溶液通过离心(10,000×g, 4℃, 2 min)提取上清液, 根据Parry等[21]的方法计算Rubisco羧化酶活性。1.2.2 抗氧化能力和膜脂过氧化程度测定 参照Zou等[20]方法测定超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性、抗坏血酸过氧化物酶(APX)活性, 参照Kumar等[22]的方法测定丙二醛(MDA)含量, 参照Su等[23]方法测定H2O2含量, 参照Ke等[24]方法测定超氧阴离子产生速率。用电导率仪(DDS-309C, ARK Instruments, Chengdu, China)测量叶片相对电导率。根据Shan和Liang[25]方法测定单脱氢抗坏血酸还原酶(MDHAR)、脱氢抗坏血酸还原酶(DHAR), 根据Loggini等[26]方法测定谷胱甘肽还原酶(GR)、谷胱甘肽过氧化物酶(GPX), 根据Li等[27]方法测定谷胱甘肽(GSH)和抗坏血酸(ASA)含量。
1.2.3 碳氮代谢相关测定 参照徐光龙[28]方法测定硝酸还原酶(NR)活性, 参照屈春媛等[29]的方法测定谷氨酰胺合成酶(GS)活性、谷氨酸合酶(GOGAT)活性和谷氨酸脱氢酶(GDH)活性, 根据Oliveira等[30]方法测定NH4+(铵态氮)和NO3-(硝态氮)含量。参照张志良[31]方法测定可溶性糖、蔗糖、果糖和淀粉含量, 参照Chopra等[32]方法测定蔗糖合成酶(SPS)和蔗糖磷酸合成酶(SS)活性。参考Tsai等[33]方法测定酸性转化酶(AI)和中性转化酶(NI)活性。
1.2.4 产量相关参数测定 在2017—2018年成熟期选取每个处理10盆, 测量单株荚数、单株粒数、单株粒重和百粒重, 计算产量缓解率和减产率。选用2018年相关生理指标测量测定值。
1.3 数据处理
采用Microsoft Excel 2010处理数据, 并用SPSS 20.0软件统计分析, 用Origin 2017作图。2 结果与分析
2.1 外源褪黑素对干旱胁迫下大豆光合特性和Rubisco活性的影响
与正常供水相比, 干旱胁迫降低了大豆叶Pn (图1-A)、Gs (图1-B)、Tr (图1-C)和Rubisco活性(图1-F), 并随着干旱胁迫的延长, 抑制作用越明显; 干旱胁迫提高了WUE (图1-E), 并随干旱胁迫时间延长呈升降升趋势; 在干旱胁迫第10天和第17天降低了Ci (图1-D), 胁迫至第24天Ci有所升高。褪黑素处理可以提高干旱胁迫下Pn、Gs、Tr和Rubisco活性, 分别增加了19.4%~44.1%、9.6%~32.5%、22.6%~42.7%和9.6%~27.8%。褪黑素处理降低了干旱胁迫下第10天和第24天WUE, 增加了第17天WUE。褪黑素处理提高了干旱胁迫第10天和第17天Ci, 降低了第24天Ci。图1
新窗口打开|下载原图ZIP|生成PPT图1外源褪黑素对干旱胁迫下大豆鼓粒期叶片光合参数和Rubisco活性的影响
A: 净光合速率; B: 气孔导度; C: 蒸腾速率; D: 胞间二氧化碳浓度; E: 水分利用率; F: 核酮糖-1,5-二磷酸羧化酶。WW: 鼓粒期开始保持80%田间持水量叶片喷施5 d清水对照; D: 鼓粒期开始停止供水保持50%田间持水量叶片喷施5 d清水干旱胁迫处理; MT+D: 鼓粒期开始停止供水保持50%田间持水量叶片喷施5 d 100 μmol L-1褪黑素加干旱胁迫处理。10: 不同处理10 d后第1次取样, WW维持80%田间持水量, D和MT+D停止供水达到50%田间持水量; 17: 不同处理17 d后第2次取样, WW维持80%田间持水量, D和MT+D第1次取样结束后维持50%田间持水量; 24: 不同处理24 d后第3次取样, WW维持80%田间持水量, D和MT+D第2次取样结束后继续维持50%田间持水量。标以不同字母的柱值在P < 0.05水平上差异显著。
Fig. 1Effect of exogenous melatonin on photosynthetic parameters and Rubisco activity of soybean during seed filling stage under drought stress
A: net photosynthetic rate; B: stomatal conductance; C: transpiration rate; D: intercellular carbon dioxide concentration; E: water use efficiency; F: ribulose-1,5-bisphosphate carboxylase. WW: keeping 80% of the field water holding capacity, from the beginning of the seed filling stage, and leaf spray with water for 5 d; D: no water supply and maintain 50% of the field water holding capacity at seed filling stage, and leaf spray with water for 5 d; MT+D: no water supply and maintaining 50% of the field water holding capacity at seed filling stage, and leaf spray with 100 μmol L-1 melatonin plus drought stress for 5 d. 10: the first sampling after 10 d of different treatments, at that time WW maintained 80% of field water holding capacity, D and MT+D stopped water supply water to reach 50% of field water holding capacity; 17: the second sampling after 17 days of different treatments, at that time WW maintained 80% of field holding water volume, D and MT+D maintained 50% field water holding capacity after the first sampling; 24: the third sampling after 24 days of different treatments, at that time WW maintained 80% field water holding capacity, D and MT+D maintained 50% field water holding capacity after the second sampling. Bars superscripted by different letters are significantly different at P < 0.05.
2.2 外源褪黑素对干旱胁迫下大豆叶绿素荧光参数的影响
与正常供水相比, 干旱胁迫降低了Fv/Fm (图2-A)、qN (图2-B)、ETR (图2-C)、ΦPSII (图2-E)和Fv/Fo (图2-F), 且干旱胁迫的延长抑制作用越明显; NPQ (图2-D)随着干旱胁迫的延长而不断上升。褪黑素处理可以缓解干旱胁迫对Fv/Fm、Fv/Fo、qN、ETR和ΦPSII的抑制; 还能缓解NPQ的上升。与干旱胁迫相比, 褪黑素处理下Fv/Fm、Fv/Fo、qN、ETR和ΦPSII分别提高了3.2%~6.1%、6.8%~19.8%、5.4%~12.4%、5.6%~30.7%和7.5%~15.9%, NPQ降低了5.7%~20.8%。图2
新窗口打开|下载原图ZIP|生成PPT图2外源褪黑素对干旱胁迫下大豆鼓粒期叶片叶绿素荧光参数的影响
A: 光系统II光能转换效率; B: 光化学猝灭系数; C: 表观电子传递速率; D: 非光化学猝灭系数; E: 光系统II实际光化学效率; F: 光系统II实际最大光能转化效率。标以不同字母的柱值在P < 0.05水平上差异显著。缩写同
Fig. 2Effects of exogenous melatonin on chlorophyll fluorescence parameters of soybean during seed filling stage under drought stress
A: photosystem II light energy conversion efficiency; B: photochemical quenching coefficient; C: apparent electron transfer rate; D: non-photochemical quenching coefficient; E: photosystem II actual photochemical efficiency; F: the actual maximum light energy conversion efficiency of photo system II. Bars superscripted by different letters are significantly different at P < 0.05. Abbreviations are the same as those given in
2.3 外源褪黑素对干旱胁迫下大豆碳代谢的影响
与正常供水相比, 干旱胁迫增加了SPS (图3-A)、SS (图3-B)、AI (图3-C)和NI (图3-D)的活性, 随着干旱胁迫的延长, 呈现先上升后下降趋势。干旱胁迫增加了可溶性糖(图3-E)、蔗糖(图3-H)和果糖含量(图3-G)并降低淀粉含量(图3-F), 随着干旱胁迫的延长, 蔗糖、果糖和可溶性糖含量呈先上升后下降趋势, 淀粉含量呈不断下降趋势。褪黑素处理提高了干旱胁迫下可溶性糖、蔗糖、果糖含量和SPS、SS、AI、NI活性, 降低淀粉含量。与干旱胁迫相比, 褪黑素处理下可溶性糖、蔗糖和果糖含量分别增加9.8%~23.5%、14.7%~21.5%和24.7%~26.8%, 淀粉含量下降10.2%~18.00%, SPS、SS、AI和NI活性分别增加4.3%~19.1%、8.2%~21.5%、11.6%~15.8%和6.3%~42.5%。图3
新窗口打开|下载原图ZIP|生成PPT图3外源褪黑素对干旱胁迫下大豆鼓粒期叶片碳代谢的影响
A: 蔗糖磷酸合酶; B: 蔗糖合酶; C: 酸性转化酶; D: 中性转化酶; E: 可溶性糖; F: 淀粉; G: 果糖; H: 蔗糖。标以不同字母的柱值在P < 0.05水平上差异显著。缩写同
Fig. 3Effects of exogenous melatonin on leaf carbon metabolism in soybean during seed filling stage under drought stress
A: sucrose phosphate synthase; B: sucrose synthase; C: acid invertase; D: neutral invertase; E: soluble sugar; F: starch; G: fructose; H: sucrose. Bars superscripted by different letters are significantly different at P < 0.05. Abbreviations are the same as those given in
2.4 外源褪黑素对干旱胁迫下大豆氮代谢的影响
与正常供水相比, 干旱胁迫增加了NH4+(图4-A)和NO3-(图4-B)的含量, 且随着干旱胁迫的延长呈先上升后下降趋势。干旱胁迫降低了GS (图4-D)和GDH (图4-E)活性, 且随着干旱胁迫的延长呈不断降低趋势; NR (图4-C)和GOGAT (图4-F)活性呈先上升后下降趋势。与干旱胁迫相比, 褪黑素处理降低了NO3-和NH4+的含量, 提高了NR、GS、GOGAT和GDH活性。图4
新窗口打开|下载原图ZIP|生成PPT图4外源褪黑素对干旱胁迫下大豆鼓粒期叶片氮代谢的影响
A: 铵态氮; B: 硝态氮; C: 硝酸还原酶; D: 谷氨酰胺合成酶; E: 谷氨酸脱氢酶; F: 谷氨酸合成酶。标以不同字母的柱值在P < 0.05水平上差异显著。缩写同
Fig. 4Effects of exogenous melatonin on nitrogen metabolism in soybean during seed filling stage under drought stress
A: ammonium nitrogen; B: nitrate nitrogen; C: nitrate reductase; D: glutamine synthetase; E: glutamate dehydrogenase; F: glutamate synthetase. Bars superscripted by different letters are significantly different at P < 0.05. Abbreviations are the same as those given in
2.5 外源褪黑素对干旱胁迫下大豆抗氧化酶活性的影响
与正常供水相比, 干旱胁迫增加了SOD (图5-A)、POD (图5-B)、CAT (图5-C)和APX (图5-D)活性, 且随胁迫延长呈现先上升后下降趋势; GR (图5-E)、GPX (图5-F)、MDHAR (图5-G)和DHAR活性(图5-H)随干旱时间延长呈不断降低趋势。褪黑素处理可以提高干旱胁迫下SOD、POD、CAT、APX、GR、GPX、MDHAR和DHAR的活性, 第10天的效果较第17天和第24天更好。图5
新窗口打开|下载原图ZIP|生成PPT图5外源褪黑素对干旱胁迫下大豆鼓粒期叶片抗氧化酶活性的影响
A: 超氧化物歧化酶; B: 过氧化物酶; C: 过氧化氢酶; D: 抗坏血酸过氧化物酶; E: 谷胱甘肽还原酶; F: 谷胱甘肽过氧化物酶; G: 单脱氢抗坏血酸还原酶; H: 脱氢抗坏血酸还原酶。标以不同字母的柱值在P < 0.05水平上差异显著。缩写同
Fig. 5Effects of exogenous melatonin on antioxidant enzyme activities in leaves of soybean during seed filling stage under drought stress
A: superoxide dismutase; B: peroxidase; C: catalase; D: ascorbate peroxidase; E: glutathione reductase; F: glutathione peroxidase; G: monodehydroascorbate reductase; H: hydrogen ascorbate reductase. Bars superscripted by different letters are significantly different at P < 0.05. Abbreviations are the same as those given in
2.6 外源褪黑素对干旱胁迫下大豆抗氧化剂含量的影响
与正常供水相比, 干旱胁迫提高了第10天和第17天GSH (图6-A)和ASA (图6-B)含量, 降低了第24天GSH含量, 并低于正常供水, 第24天ASA含量较第17天有所降低但仍高于正常供水。褪黑素处理可以增加干旱胁迫下ASA和GSH的含量, 其中GSH含量增幅在第17天效果更好, 而ASA含量增幅在第10天效果更好。图6
新窗口打开|下载原图ZIP|生成PPT图6外源褪黑素对干旱胁迫下大豆鼓粒期叶片抗氧化剂含量的影响
A: 谷胱甘肽; B: 抗坏血酸。标以不同字母的柱值在P < 0.05水平上差异显著。缩写同
Fig. 6Effects of exogenous melatonin on antioxidants in leaves of soybean during seed filling stage under drought stress
A: glutathione; B: ascorbic acid. Bars superscripted by different letters are significantly different at P < 0.05. Abbreviations are the same as those given in
2.7 外源褪黑素对干旱胁迫下大豆膜脂过氧化的影响
与正常供水相比, 干旱胁迫增加了O2-产生速率(图7-A)、H2O2含量(图7-B)、MDA含量(图7-C)和REL (图7-D), 且随着干旱胁迫的延长呈不断上升趋势。褪黑素处理可以减轻干旱胁迫下的O2-产生速率、H2O2含量, 以及MDA含量和REL的上升, 且第10天的效果更好。图7
新窗口打开|下载原图ZIP|生成PPT图7外源褪黑素对干旱胁迫下大豆鼓粒期叶片膜脂过氧化的影响
A: 超氧阴离子产生速率; B: 过氧化氢含量; C: 丙二醛含量; D: 相对电导率。标以不同字母的柱值在P < 0.05水平上差异显著。缩写同
Fig. 7Effects of exogenous melatonin on membrane lipid peroxidation in soybean during seed filling stage under drought stress
A: superoxide anion production rate; B: hydrogen peroxide content; C: malondialdehyde content; D: relative conductivity. Bars superscripted by different letters are significantly different at P < 0.05. Abbreviations are the same as those given in
2.8 外源褪黑素对干旱胁迫下大豆产量的影响
由表1可知, 干旱胁迫(D)降低鼓粒期大豆单株荚数、单株粒数、单株粒重和百粒重。褪黑素处理可提高干旱胁迫下单株荚数、单株粒数、单株粒重和百粒重。与干旱胁迫相比, 单株荚数、单株粒数、单株粒重和百粒重2017年分别提高了1.9%、0.7%、13.2%、18.1%; 2018年分别提高了4.0%、0.9%、16.2%、16.4%。Table 1
表1
表1外源褪黑素对干旱胁迫下鼓粒期大豆产量以及减产率和缓解率的影响
Table 1
| 年份 Year | 处理 Treatment | 单株荚数 Pods per plant | 单株粒数 Seeds per pod | 单株粒重 Grain weight per plant (g) | 百粒重 Hundred grain weigh (g) | 减产率 Yield reduction rate (%) | 缓解率 Remission rate (%) |
|---|---|---|---|---|---|---|---|
| 2017 | MT+D | 24.80±1.52 a | 46.63±6.92 a | 9.75±0.83 b | 16.55±2.21 b | ||
| D | 24.32±2.15 a | 46.27±4.47 a | 8.61±1.42 bc | 14.01±1.19 c | -24.6 | 9.9 | |
| WW | 25.80±1.40 a | 47.70±3.40 a | 11.42±1.89 a | 20.78±0.83 a | |||
| 2018 | MT+D | 22.08±0.64 ab | 42.53±1.90 ab | 7.01±0.72 c | 16.11±1.24 b | ||
| D | 21.23±0.75 ab | 42.13±1.98 ab | 6.03±0.43 cd | 13.76±0.91 c | -36.3 | 10.3 | |
| WW | 22.54±0.14 ab | 42.67±2.63 ab | 9.47±0.27 b | 21.52±0.91 a |
新窗口打开|下载CSV
3 讨论
干旱胁迫降低植株叶绿体光能复合体电子传递能力和CO2固定效率, NADP+供应减少, 导致在PSI中生产O2-, 又经PSII生产H2O2[34]。植物会激发酶促系统和非酶促系统来清除过量ROS, 包括抗氧化酶和抗氧化剂[35]。本试验研究发现, 干旱胁迫第10天会显著提高SOD、POD、CAT和APX活性, 干旱胁迫至第24天, 抗氧化酶活性低于对照。Huang等[15]研究表明玉米幼苗在干旱胁迫下外源褪黑素提升抗氧化酶活性。本研究同样发现褪黑素处理较干旱胁迫可提高抗氧化酶活性, 在处理第10天和17天提高幅度较大, 在第24天增幅较小, 这可能与胁迫时间延长或褪黑素生理功能下降有关。褪黑素并不具有直接清除ROS的功能[36], 褪黑素对氧化还原稳态的调节是由于其诱导抗氧化酶活性提高。SOD作为ROS清除的第一道防线, 可将O2-歧化为O2和H2O2, CAT能清除过氧化物酶体中H2O2[37]。在线粒体过氧化物酶中存在ASA-GSH循环酶系统, 包括MDHAR、DHAR、GR和GPX共同参与H2O2的清除过程, 并参与ASA和GSH循环再生过程[19]。据研究表明干旱胁迫提高玉米叶片MDHAR、DHAR、GR和GPX 活性[38]。本试验表明, 干旱胁迫会降低MDHAR、DHAR、GR和GPX活性, 鼓粒期作为最后一个时期自身防御系统较弱, 对胁迫更敏感。褪黑素能促进西瓜ASA-GSH循环中APX和MDHAR活性, 增加ASA和GSH含量, 减轻ROS积累和随后的氧化应激[27]。本研究表明褪黑素处理显著提高了干旱胁迫下MDHAR、DHAR、GR和GPX活性, 平衡氧化还原稳态以及促进GSH和ASA含量的再生循环, 这有助于清除过量ROS、APX以ASA为底物, 在ASA-GSH循环中将H2O2还原为H2O, 产生MDHA后再产生MDHAR; GSH和ASA可直接与HO2-、O2-和1O2等ROS反应, 将有机自由基R还原为RH。这些结果表明, 褪黑素可通过激活大豆叶片的整个抗氧化系统来改善细胞氧化还原稳态, 从而保护细胞免受干旱胁迫诱导的氧化应激[39]。
ROS的产生与清除平衡机制是其含量的基础, ROS作为信使诱导抗氧化酶基因表达, 但过量的ROS促进抗氧化酶活性提升并不足以清除它们。ROS还会转移到类囊体和细胞膜, 引发膜脂过氧化, 从而破坏膜结构[40]。干旱胁迫程度加深会持续提高ROS和MDA含量积累[41], 本试验表明, 随着干旱胁迫时间延长, H2O2含量、O2-产生速率、MDA含量和相对电导率呈现不断上升, 说明干旱胁迫导致ROS过度积累, 细胞膜受到损伤, 电解质外渗增加。褪黑素处理缓解了干旱胁迫下H2O2和MDA的积累, 以及相对电导率的下降, 说明褪黑素调节膜脂过氧化渗透平衡, 保护细胞膜系统完整性, 主要原因与褪黑素可以增强大豆叶片抗氧化酶活性有关, 也与褪黑素具有抑制膜质过氧化的级联反应有关[42], 这有助于清除部分过量ROS积累, 缓解细胞膜损伤、光合色素降解、蛋白质大分子降解等。
光合作用是作物生长发育过程中重要的能量转化代谢系统, 提高光合能力有助于为植物生长发育、籽粒生物量积累奠定基础, 是作物产量形成的物质基础[43]。在本研究中, 干旱胁迫条件下, 植物通过关闭气孔以减少水分流失, Gs和Tr下降, 气孔关闭导致吸收CO2不足而抑制光合作用[44], 长期干旱胁迫提高Ci, 可能与非气孔限制有关, 说明干旱胁迫已损伤光合系统和叶组织, 空气中CO2直接通过叶片缝隙进入叶片内部, 抑制了对光能的吸收, 降低了光合作用正常运行和碳同化过程, 阻碍了光反应形态的同化力还原蔗糖的能力[45]。本试验表明褪黑素处理可以缓解干旱胁迫下Pn、Gs、Tr和叶绿素含量的下降, 在第24天降低了Ci说明褪黑素处理Pn下降是气孔限制因素, 缓解了干旱胁迫对光合系统的伤害, 这与之前的研究结果一致[15,20,41,46-47]。褪黑素处理缓解了干旱胁迫对光能吸收利用抑制, 提高碳同化产物蔗糖含量和叶片对籽粒运输能力, 有助于生长发育和产量提升。
PSII的部分激发能通过电子传递为CO2固定提供能量, 干旱胁迫降低了光合速率, 导致吸收的光能过剩, 不能散失的光能为ROS积累提供能量, 对光合系统产生损伤或者以热的形式散发[48]。本试验表明, 干旱胁迫降低Fv/Fm、Fv/Fo、ΦPSII、ETR和qN, 提高NPQ, 说明干旱胁迫对光合系统产生损伤, 降低了光合转化效率。Ye等[46]研究发现外源褪黑素能提高干旱胁迫下玉米幼苗叶绿素荧光。本试验表明, 褪黑素处理可以提高干旱胁迫下大豆叶片Fv/Fm、Fv/Fo、ΦPSII、ETR和qN, 降低NPQ; 说明褪黑素处理能缓解干旱对光合系统的损伤, 提高光能利用效率和电子传递能力, 并对ROS积累有一定抑制作用。
碳代谢与植株生长和产量密切相关, 在植株遭受干旱胁迫时, 叶片光合速率下降, 光合同化物形成量减少, 糖类物质含量增加, 光呼吸活性提高, 以蔗糖为主要运输形式的光合同化物加速向根系转运[49]。Wei等[47]研究表明, 褪黑素能上调盐胁迫下大豆碳代谢中丙酮酸转运能力和葡萄糖和果糖间转化水平。本试验表明, 褪黑素能提高干旱胁迫下蔗糖和果糖含量, SS、SPS、NI和AI活性, 降低淀粉含量, SPS和SS能够催化合成蔗糖, NI和AI促进蔗糖和淀粉向己糖方向转化, 导致果糖在叶片中积累以及在碳水化合物之间转化[45], 大量积累的己糖不仅维持细胞膨压稳定, 又反馈抑制光合作用, 淀粉与蔗糖存在相互转换功能, 淀粉含量降低可能与褪黑素降低了干旱胁迫下磷酸丙酮转化淀粉能力或者提高了大豆叶片内淀粉分解酶活性有关。提高糖的积累合成和转化能力, 能提高渗透调节平衡以维持正常的细胞势, 还能为同化物运输提供能量, 为氮代谢提供碳源和能量, 促进蛋白质和氨基酸的合成[50]。
氮代谢对作物的生长发育、产量形成具有重要的生理作用, 氮代谢为碳骨架提供蛋白[51]。干旱胁迫降低氮代谢相关酶的活性, 增加氮分解代谢酶活性[52]。本研究发现, 干旱胁迫会降低氮代谢相关酶活性从而降低NO3-和NH4+同化能力, 因GDH与α-酮戊二酸同化NH4与NH4+合成谷氨酸, 再通过GS和GOGAT合成各种氨基酸, 因此抑制蛋白质、叶绿素和核酸等多种含氮化合物的合成。Zhang等[53]研究表明, 外源褪黑素可提升NaHCO3胁迫下下黄瓜幼苗叶片的氮代谢水平。本研究表明, 外源褪黑素能提高干旱胁迫下大豆叶片氮代谢相关酶的活性, 这有助于促进氮代谢过程中同化能力, 缓解因NO3-和NH4+的积累形成氨毒, 对维持大豆正常生长、叶绿素合成等具有促进作用。
干旱胁迫会抑制植物生长和发育进程、营养物质的合成与转运、光合作用以及基因和蛋白水平表达, 改变形态结构、相关酶活性和水分分配方向[39]。而产量与光合作用直接相关, 抗逆性可维护细胞膜结构, 氧化还原稳态, 以及保护碳氮代谢的同化物吸收转运, 保护蛋白质分子结构合成叶绿体等细胞器和蔗糖-淀粉代谢等, 从而维护光合作用正常运行。本研究发现, 干旱胁迫通过降低百粒重来降低产量, 说明干旱胁迫抑制了子粒的生长, 或许与减缓光合同化物向子粒运输有一定关系。褪黑素能缓解干旱胁迫对百粒重的抑制和叶片的结构损伤, 促进碳氮同化能力和光合能力, 这可能会加速向子粒运输光合产物促进子粒发育进而提高产量。
4 结论
外源褪黑素提高了干旱胁迫下大豆叶片中抗氧化酶活性和抗氧剂含量, 从而减少ROS积累, 降低了膜脂过氧化程度, 保护PSII系统提高电子传递和利用效率, 提升光合能力和碳氮代谢同化能力。此外, 与正常供水相比, 褪黑素减少了干旱胁迫下产量损失, 2017年干旱胁迫降低了24.6%产量, 褪黑素处理缓解因干旱胁迫造成9.9%的产量损失; 2018年干旱胁迫降低了36.3%产量, 褪黑素处理缓解了因干旱造成的10.3%的产量损失。参考文献 原文顺序
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被引期刊影响因子
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DOI:10.1371/journal.pone.0214977URLPMID:31498795 [本文引用: 1]
Effects of environmental stressors on the parent may be transmitted to the F1 generation of plants that support global food, oil, and energy production for humans and animals. This study was conducted to determine if the effects of drought stress on parental soybean plants are transmitted to the F1 generation. The germination and seedling vigor of F1 soybean whose maternal parents, Asgrow AG5332 and Progeny P5333RY, were exposed to soil moisture stress, that is, 100, 80, 60, 40, and 20% replacement of evapotranspiration (ET) during reproductive growth, were evaluated under controlled conditions. Pooled over cultivars, effects of soil moisture stress on the parents caused a reduction in the seed germination rate, maximum seed germination, and overall seedling performance in the F1 generation. The effect of soil moisture stress on the parent environment induced seed quality that carried on the F1 generation seed gemination and seedling traits under optimum conditions and further exasperated when exposed to increasing levels of drought stress. Results indicate that seed weight and storage reserve are key factors positively associated with germination traits and seedling growth. Our data confirm that the effects of soil moisture stress on soybean are transferable, causing reduced germination, seedling vigor, and seed quality in the F1 generation. Therefore, optimal water supply during soybean seed formation period may be beneficial for seed producers in terms of optimizing seed quality and vigor characteristics of commodity seed.
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DOI:10.1093/jxb/err402URLPMID:22282535 [本文引用: 1]
Visible light is the basic energetic driver of plant biomass production through photosynthesis. The constantly fluctuating availability of light and other environmental factors means that the photosynthetic apparatus must be able to operate in a dynamic fashion appropriate to the prevailing conditions. Dynamic regulation is achieved through an array of homeostatic control mechanisms that both respond to and influence cellular energy and reductant status. In addition, light availability and quality are continuously monitored by plants through photoreceptors. Outside the laboratory growth room, it is within the context of complex changes in energy and signalling status that plants must regulate pathways to deal with biotic challenges, and this can be influenced by changes in the highly energetic photosynthetic pathways and in the turnover of the photosynthetic machinery. Because of this, defence responses are neither simple nor easily predictable, but rather conditioned by the nutritional and signalling status of the plant cell. This review discusses recent data and emerging concepts of how recognized defence pathways interact with and are influenced by light-dependent processes. Particular emphasis is placed on the potential roles of the chloroplast, photorespiration, and photoreceptor-associated pathways in regulating the outcome of interactions between plants and pathogenic organisms.
DOI:10.1016/j.tplants.2010.11.006URLPMID:21183394 [本文引用: 1]
Plants need a highly responsive regulatory system to keep photosynthetic light reactions in balance with the needs and restrictions of the downstream metabolism. This mechanism optimises plant growth under naturally fluctuating light conditions. In this opinion article, we present a model addressing the biological role of the light intensity-controlled phosphorylation of light-harvesting complex II (LHCII) proteins and its relation with the non-photochemical quenching of excitation energy (NPQ). We overturn a long held view of the possible role of 'state transitions'. Instead, we discuss the interplay between LHCII protein phosphorylation and NPQ, a mechanism that is crucial for regulating excitation energy distribution to the two photosystems (PSII and PSI) and balancing the intersystem electron flow despite constant fluctuations in light intensity.
DOI:10.1093/pcp/pcp082URLPMID:19546148 [本文引用: 1]
Drought stress is a major constraint to the production and yield stability of soybean [Glycine max (L.) Merr.]. For developing high yielding varieties under drought conditions, the most widely employed criterion has traditionally been direct selection for yield stability over multiple locations. However, this approach is time consuming and labor intensive, because yield is a highly quantitative trait with low heritability, and influenced by differences arising from soil heterogeneity and environmental factors. The alternative strategy of indirect selection using secondary traits has succeeded only in a few crops, due to problems with repeatability and lack of phenotyping strategies, especially for root-related traits. Considerable efforts have been directed towards identifying traits associated with drought resistance in soybean. With the availability of the whole genome sequence, physical maps, genetics and functional genomics tools, integrated approaches using molecular breeding and genetic engineering offer new opportunities for improving drought resistance in soybean. Genetic engineering for drought resistance with candidate genes has been reported in the major food crops, and efforts for developing drought-resistant soybean lines are in progress. The objective of this review is to consolidate the current knowledge of physiology, molecular breeding and functional genomics which may be influential in integrating breeding and genetic engineering approaches for drought resistance in soybean.
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[本文引用: 1]
DOI:10.3724/SP.J.1006.2014.00487URL [本文引用: 1]
在土培条件下，以对1,2,4-三氯苯(TCB)敏感性显著差异的宁粳1号(敏感)和扬辐粳8号(耐性)为对象，研究了不同浓度1,2,4-三氯苯(TCB)胁迫对两种水稻分蘖盛期生长和生理特性的影响。结果表明，不同浓度TCB胁迫下，敏感基因型宁粳1号最长根长、株高、单穴分蘖数、地上部和地下部干物重随胁迫程度加深均显著递减; 耐性基因型扬辐粳8号在低浓度(20 mg kg-1) TCB胁迫下，最长根长、地上部和地下部干物重极显著增加，当中高浓度(40 mg kg-1、60 mg kg-1) TCB胁迫时，最长根长、株高、单穴分蘖数、地上部和地下部干物重显著下降。不同浓度TCB胁迫下，敏感基因型宁粳1号根系活力、叶绿素含量、叶片和根系可溶性蛋白质含量相对较低，叶片和根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性明显降低，O2?产生速率和丙二醛(MDA)含量显著增高; 耐性基因型扬辐粳8号在低浓度(20 mg kg-1) TCB胁迫下，根系活力、叶片和根系的可溶性蛋白含量、SOD、POD、CAT活性极显著增加，O2?产生速率和MDA含量极显著降低，当中等浓度(40 mg kg-1) TCB胁迫时，SOD、POD、CAT活性虽然增强，但O2?产生速率显著增加，MDA大量积累，当高浓度(60 mg kg-1) TCB胁迫时，其根系活力、叶绿素含量极显著降低，根系中SOD、CAT活性显著降低，O2?产生速率和MDA含量显著增加。总之，低浓度TCB胁迫下，长势良好、叶片和根系可溶性蛋白质含量高、抗氧化系统清除活性氧能力强、膜脂过氧化程度低是耐性基因型扬辐粳8号区别于敏感型宁粳1号的主要特征。
DOI:10.3724/SP.J.1006.2014.00487URL [本文引用: 1]
在土培条件下，以对1,2,4-三氯苯(TCB)敏感性显著差异的宁粳1号(敏感)和扬辐粳8号(耐性)为对象，研究了不同浓度1,2,4-三氯苯(TCB)胁迫对两种水稻分蘖盛期生长和生理特性的影响。结果表明，不同浓度TCB胁迫下，敏感基因型宁粳1号最长根长、株高、单穴分蘖数、地上部和地下部干物重随胁迫程度加深均显著递减; 耐性基因型扬辐粳8号在低浓度(20 mg kg-1) TCB胁迫下，最长根长、地上部和地下部干物重极显著增加，当中高浓度(40 mg kg-1、60 mg kg-1) TCB胁迫时，最长根长、株高、单穴分蘖数、地上部和地下部干物重显著下降。不同浓度TCB胁迫下，敏感基因型宁粳1号根系活力、叶绿素含量、叶片和根系可溶性蛋白质含量相对较低，叶片和根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性明显降低，O2?产生速率和丙二醛(MDA)含量显著增高; 耐性基因型扬辐粳8号在低浓度(20 mg kg-1) TCB胁迫下，根系活力、叶片和根系的可溶性蛋白含量、SOD、POD、CAT活性极显著增加，O2?产生速率和MDA含量极显著降低，当中等浓度(40 mg kg-1) TCB胁迫时，SOD、POD、CAT活性虽然增强，但O2?产生速率显著增加，MDA大量积累，当高浓度(60 mg kg-1) TCB胁迫时，其根系活力、叶绿素含量极显著降低，根系中SOD、CAT活性显著降低，O2?产生速率和MDA含量显著增加。总之，低浓度TCB胁迫下，长势良好、叶片和根系可溶性蛋白质含量高、抗氧化系统清除活性氧能力强、膜脂过氧化程度低是耐性基因型扬辐粳8号区别于敏感型宁粳1号的主要特征。
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DOI:10.1093/jxb/ert074URLPMID:23580751 [本文引用: 1]
Drought stress is a major factor limiting symbiotic nitrogen fixation (NF) in soybean crop production. However, the regulatory mechanisms involved in this inhibition are still controversial. Soybean plants were symbiotically grown in a split-root system (SRS), which allowed for half of the root system to be irrigated at field capacity while the other half remained water deprived. NF declined in the water-deprived root system while nitrogenase activity was maintained at control values in the well-watered half. Concomitantly, amino acids and ureides accumulated in the water-deprived belowground organs regardless of transpiration rates. Ureide accumulation was found to be related to the decline in their degradation activities rather than increased biosynthesis. Finally, proteomic analysis suggests that plant carbon metabolism, protein synthesis, amino acid metabolism, and cell growth are among the processes most altered in soybean nodules under drought stress. Results presented here support the hypothesis of a local regulation of NF taking place in soybean and downplay the role of ureides in the inhibition of NF.
DOI:10.1111/pce.12285URL [本文引用: 1]
Symbiotic nitrogen fixation is one of the first physiological processes inhibited in legume plants under water-deficit conditions. Despite the progress made in the last decades, the molecular mechanisms behind this regulation are not fully understood yet. Recent proteomic work carried out in the model legume Medicago truncatula provided the first indications of a possible involvement of nodule methionine (Met) biosynthesis and related pathways in response to water-deficit conditions. To better understand this involvement, the drought-induced changes in expression and content of enzymes involved in the biosynthesis of Met, S-adenosyl-L-methionine (SAM) and ethylene in M.truncatula root and nodules were analyzed using targeted approaches. Nitrogen-fixing plants were subjected to a progressive water deficit and a subsequent recovery period. Besides the physiological characterization of the plants, the content of total sulphur, sulphate and main S-containing metabolites was measured. Results presented here show that S availability is not a limiting factor in the drought-induced decline of nitrogen fixation rates in M.truncatula plants and provide evidences for a down-regulation of the Met and ethylene biosynthesis pathways in roots and nodules in response to water-deficit conditions.
DOI:10.1016/j.pbi.2011.02.001URLPMID:21377404 [本文引用: 1]
Plant hormones play central roles in the ability of plants to adapt to changing environments, by mediating growth, development, nutrient allocation, and source/sink transitions. Although ABA is the most studied stress-responsive hormone, the role of cytokinins, brassinosteroids, and auxins during environmental stress is emerging. Recent evidence indicated that plant hormones are involved in multiple processes. Cross-talk between the different plant hormones results in synergetic or antagonic interactions that play crucial roles in response of plants to abiotic stress. The characterization of the molecular mechanisms regulating hormone synthesis, signaling, and action are facilitating the modification of hormone biosynthetic pathways for the generation of transgenic crop plants with enhanced abiotic stress tolerance.
DOI:10.1093/jxb/err256URLPMID:22016420 [本文引用: 1]
The presence of melatonin in plants is universal. Evidence has confirmed that a major portion of the melatonin is synthesized by plants themselves even though a homologue of the classic arylalkylamine N-acetyltransferase (AANAT) has not been identified as yet in plants. Thus, the serotonin N-acetylating enzyme in plants may differ greatly from the animal AANAT with regard to sequence and structure. This would imply multiple evolutionary origins of enzymes with these catalytic properties. A primary function of melatonin in plants is to serve as the first line of defence against internal and environmental oxidative stressors. The much higher melatonin levels in plants compared with those found in animals are thought to be a compensatory response by plants which lack means of mobility, unlike animals, as a means of coping with harsh environments. Importantly, remarkably high melatonin concentrations have been measured in popular beverages (coffee, tea, wine, and beer) and crops (corn, rice, wheat, barley, and oats). Billions of people worldwide consume these products daily. The beneficial effects of melatonin on human health derived from the consumption of these products must be considered. Evidence also indicates that melatonin has an ability to increase the production of crops. The mechanisms may involve the roles of melatonin in preservation of chlorophyll, promotion of photosynthesis, and stimulation of root development. Transgenic plants with enhanced melatonin content could probably lead to breakthroughs to increase crop production in agriculture and to improve the general health of humans.
DOI:10.3389/fpls.2019.00677URLPMID:31178885 [本文引用: 3]
The protective role of melatonin in plants against various abiotic stresses have been widely demonstrated, but poorly explored in organ-specific responses and the transmission of melatonin signals across organs. In this study, the effects of melatonin with the root-irrigation method and the leaf-spraying method on the antioxidant system and photosynthetic machinery in maize seedlings under drought stress were investigated. The results showed that drought stress led to the rise in reactive oxygen species (ROS), severe cell death, and degradation of D1 protein, which were mitigated by the melatonin application. The application of melatonin improved the photosynthetic activities and alleviated the oxidative damages of maize seedlings under the drought stress. Compared with the leaf-spraying method, the root-irrigation method was more effective on enhancing drought tolerance. Moreover, maize seedlings made organ-specific physiological responses to the drought stress, and the physiological effects of melatonin varied with the dosage, application methods and plant organs. The signals of exogenous melatonin received by roots could affect the stress responses of leaves, and the melatonin signals perceived by leaves also led to changes in physiological metabolisms in roots under the stress. Consequently, the whole seedlings coordinated the different parts and made a systemic acclimation against the drought stress. Melatonin as a protective agent against abiotic stresses has a potential application prospect in the agricultural industry.
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DOI:10.1007/s00425-018-2881-2URLPMID:29564630 [本文引用: 1]
Melatonin-mediated osmotic tolerance was attributed to increased antioxidant capacity, energy metabolism, osmoregulation and autophagy in wheat (Triticum aestivum L.). Melatonin is known to play multiple roles in plant abiotic stress tolerance. However, its role in wheat has been rarely investigated. In this study, 25% polyethylene glycol 6000 (PEG 6000) was used to simulate osmotic stress, and wheat seeds and seedlings were treated with different concentrations of melatonin under PEG stress. Isobaric tag for relative and absolute quantification (iTRAQ)-based proteomic techniques were used to identify the differentially accumulated proteins from melatonin-treated and non-treated seedlings. Seeding priming with melatonin significantly increased the germination rate, coleoptile length, and primary root number of wheat under PEG stress, as well as the fresh weight, dry weight, and water content of wheat seedlings. Under PEG stress, melatonin significantly improved reactive oxygen species homeostasis, as revealed by lower H2O2 and O 2· content; and the expression of antioxidant enzymes at the transcription and translation levels was increased. Melatonin maintained seedling growth by improving photosynthetic rates and instantaneous and intrinsic water use efficiencies, as well as carbon fixation and starch synthesis at the protein level. Melatonin treatment significantly affected the expression of glycolytic proteins, including fructose-1,6-bisphosphate aldolase, hexokinase, glyceraldehyde-3-phosphate dehydrogenase, and enolase, and remarkably increased the expression of the nicotinamide adenine dinucleotide transporter and nicotinamide adenine dinucleotide binding protein, thereby indirectly modulating electron transport in the respiratory chain. This indicated that melatonin improved energy production in PEG-stressed seedlings. Further, melatonin played a regulatory role in autophagy, protease expression, and ubiquitin-mediated protein degradation by significantly upregulating rab-related protein, fused signal recognition particle receptor, aspartyl protease, serine protease, ubiquitin-fold modifier 1, and ubiquitin at the mRNA or protein level. These findings suggested that melatonin might activate a metabolic cascade related to autophagy under PEG stress in wheat seedlings.
DOI:10.1016/j.plaphy.2017.06.014URLPMID:28633086 [本文引用: 1]
Melatonin plays an important role in abiotic stress in plant, but its role in wheat drought tolerance is less known. To verify its role, wheat seedlings (Triticum aestivum L. 'Yan 995') at 60% and 40% of field capacity were treated with 500?μM melatonin in this study. Melatonin treatment significantly enhanced the drought tolerance of wheat seedlings, as demonstrated by decreased membrane damage, more intact grana lamella of chloroplast, higher photosynthetic rate, and maximum efficiency of photosystem II, as well as higher cell turgor and water holding capacity in melatonin-treated seedlings. Besides, melatonin markedly decreased the content of hydrogen peroxide and superoxide anion in melatonin-treated seedlings, which is attributed to the increased total antioxidant capacity, GSH and AsA contents, as well as enzyme activity including ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione peroxidase (GPX), and glutathione transferase (GST). The GSH-AsA related genes including APX, MDHAR, and DHAR were commonly upregulated by melatonin and correlated to the antioxidant enzyme activity as well as the content of GSH and AsA, indicating that the increase of GSH and AsA was attributed to the expression of these genes. Our result confirmed the mitigation potential of melatonin in drought stress and certain mechanisms of melatonin-induced GSH and AsA accumulation, which could deepen our understanding of melatonin-induced drought tolerance in wheat.
DOI:10.1016/j.scienta.2016.05.003URL [本文引用: 2]
DOI:10.32615/ps.2019.066URL [本文引用: 3]
DOI:10.1046/j.1365-3040.1997.d01-85.xURL [本文引用: 1]
DOI:10.1104/pp.102.1.115URLPMID:12231802 [本文引用: 1]
Previous research has shown that cell membranes of potato (Solanum tuberosum L. cv Russet Burbank) seed-tubers lose integrity between 7 and 26 months of storage (4[deg]C, 95% relative humidity), and this loss coincides with a significant decrease in growth potential. The age-induced decline in membrane integrity is apparently due to increased peroxidative damage of membrane lipids. Malondialdehyde (MDA) and ethane concentrations (sensitive markers of lipid peroxidation and membrane damage) increased in seed-tuber tissues with advancing age. Moreover, in vivo ethane production from discs of cortex tissue from 13- and 25-month-old seed-tubers was 87% greater (on average) than that from discs from 1-month-old tubers. Calcium suppressed ethane production from all ages of tissue discs, and the effect was concentration dependent. Linoleic acid enhanced ethane production from 5- and 17-month-old tubers by 61 and 228%, respectively, suggesting that older tissue may contain a higher free-radical (FR) titer and/or lower free polyunsaturated fatty acid content. In addition, throughout plant establishment, the internal ethane concentration of older seed-tubers was 54% higher than that of younger seed-tubers. MDA concentration of tuber tissue declined by about 65% during the initial 7 months of storage and then increased 267% as tuber age advanced to 30 months. The age-induced trend in tuber reducing sugar concentration was similar to that of MDA, and the two were linearly correlated. The age-dependent increase in reducing sugars may thus reflect peroxidative degeneration of the amyloplast membrane, leading to increased starch hydrolysis. Compared with 5-month-old seed tubers, 17- and 29-month-old seed-tubers had significantly higher levels of lipofuscin-like fluorescent compounds (FCs), which are produced when MDA reacts with free amino acids. Age-dependent increases in MDA, ethane, and FCs were not associated with higher activities of phospholipase and lipoxygenase in tissue from older tubers. In fact, 8-month-old seed-tubers had significantly higher activities of these enzymes than 20-month-old seed-tubers. However, the activities of superoxide dismutase, peroxidase, and catalase in 20-month-old tubers were substantially higher out of storage, and increased at a faster rate during plant establishment, than in 8-month-old seed-tubers. Collectively, these results suggest that a gradual build-up of FRs leads to peroxidative damage of membrane lipids during aging of potato seed-tubers.
DOI:10.1016/j.jplph.2005.04.033URLPMID:16425447 [本文引用: 1]
In order to analyze the relationship between polyamine oxidative degradation induced by light and the Lignin synthesis in cell walls, the activities of diamine oxidases and peroxidase, the contents of H2O2 and lignin, and the growth of hypocotyls in soybean [Glycine max (Linn.) Merr.] grown under tight or in darkness were investigated. In comparison with the dark treatment, light irradiation significantly inhibited the growth of soybean hypocotyls and promoted the activities of diamine oxidases and peroxidase as well as the accumulation of H2O2 and lignin. Treatments with the different concentrations of diamine oxidase inhibitors (2-hydroxyethylhydrazine and aminoguanidine) under the light condition inhibited diamine oxidase activity, and decreased the contents of H2O2 and lignin. The results provide evidence for the hypothesis that light irradiation could promote the accumulation of H2O2 and lignin in cell walls by activating polyamine oxidative degradation mediated by diamine oxidases.
DOI:10.1007/s10725-006-9150-2URL [本文引用: 1]
The activity of 1-aminocyclopropane-1-carboxylic acid synthase (ACC synthase, ACS) and the concentrations of superoxide radical (O2−.) and hydrogen peroxide (H2O2) were measured in etiolated mungbean seedlings following their transfer to a growth chamber at 25°C after a 5-h-chilling treatment at 5°C. All of these variables increased dramatically after the transfer, and strong correlations were found between ACS activity and the concentrations of superoxide and H2O2. Exogenous applications of two generators of superoxide radicals, methylviologen (MV) and xanthine–xanthine oxidase (X–XOD), enhanced ACS activity in seedlings, but their effects were inhibited by exogenous applications of specific scavengers of O2−.. However, applications of H2O2 or specific H2O2-scavengers had no significant effects on seedlings ACS activity. The results indicate that O2−. was involved in the chilling-induced increases in ACS activity, but not H2O2. ACS activity peaked ca. 8h after the transfer, and then declined, but the decline could be counteracted by exogenous applications of specific O2−. scavengers, this suggests that damage was caused by superoxide radicals influencing ACS activity in etiolated mungbean seedlings. Further analysis of changes in two key kinetic parameters of ACS activity—V max (maximum velocity) and K m (the Michaelis constant)—in the seedlings indicated that the presence of O2−. may reduce K m, i.e. increase substrate (S-adenosyl methionine, SAM) affinity. That would be the main mechanism responsible for the observed chilling-induced increases in ACS activity in etiolated mungbean seedlings.
DOI:10.1016/j.plantsci.2009.11.002URL [本文引用: 1]
DOI:10.1104/pp.119.3.1091URLPMID:10069848 [本文引用: 1]
We analyzed antioxidative defenses, photosynthesis, and pigments (especially xanthophyll-cycle components) in two wheat (Triticum durum Desf.) cultivars, Adamello and Ofanto, during dehydration and rehydration to determine the difference in their sensitivities to drought and to elucidate the role of different protective mechanisms against oxidative stress. Drought caused a more pronounced inhibition in growth and photosynthetic rates in the more sensitive cv Adamello compared with the relatively tolerant cv Ofanto. During dehydration the glutathione content decreased in both wheat cultivars, but only cv Adamello showed a significant increase in glutathione reductase and hydrogen peroxide-glutathione peroxidase activities. The activation states of two sulfhydryl-containing chloroplast enzymes, NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase and fructose-1,6-bisphosphatase, were maintained at control levels during dehydration and rehydration in both cultivars. This indicates that the defense systems involved are efficient in the protection of sulfhydryl groups against oxidation. Drought did not cause significant effects on lipid peroxidation. Upon dehydration, a decline in chlorophyll a, lutein, neoxanthin, and beta-carotene contents, and an increase in the pool of de-epoxidized xanthophyll-cycle components (i.e. zeaxanthin and antheraxanthin), were evident only in cv Adamello. Accordingly, after exposure to drought, cv Adamello showed a larger reduction in the actual photosystem II photochemical efficiency and a higher increase in nonradiative energy dissipation than cv Ofanto. Although differences in zeaxanthin content were not sufficient to explain the difference in drought tolerance between the two cultivars, zeaxanthin formation may be relevant in avoiding irreversible damage to photosystem II in the more sensitive cultivar.
DOI:10.3389/fpls.2017.00295URLPMID:28298921 [本文引用: 2]
Melatonin, a pleiotropic signal molecule, has been shown to play important roles in the regulation of plant growth, development, and responses to environmental stresses. Since a few species have been investigated to unveil the effect of exogenous melatonin on salt stress, the underlying mechanism of melatonin-mediated salt stress tolerance in other plant species still remains largely unknown. In this study, the effects of melatonin on leaf photosynthesis and redox homeostasis in watermelon were examined under salt stress (300 mM NaCl) along with different doses of melatonin (50, 150, and 500 μM) pretreatment. NaCl stress inhibited photosynthesis and increased accumulation of reactive oxygen species and membrane damage in leaves of watermelon seedlings. However, pretreatment with melatonin on roots alleviated NaCl-induced decrease in photosynthetic rate and oxidative stress in a dose-dependent manner. The protection of photosynthesis by melatonin was closely associated with the inhibition of stomatal closure and improved light energy absorption and electron transport in photosystem II, while the reduction of oxidative stress by melatonin was attributed to the improved redox homeostasis coupled with the enhanced activities of antioxidant enzymes. This study unraveled crucial role of melatonin in salt stress mitigation and thus can be implicated in the management of salinity in watermelon cultivation.
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DOI:10.1016/j.plaphy.2013.02.015URLPMID:23500717 [本文引用: 1]
Although nitrate (NO3(-)) but not ammonium (NH4(+)) improves plant tolerance to oxygen deficiency, the mechanisms involved in this phenomenon are just beginning to be understood. By using gas chromatography-mass spectrometry, we investigated the metabolic fate of (15)NO3(-) and (15)NH4(+) in soybean plants (Glycine max L. Merril cv. IAC-23) subjected to root hypoxia. This stress reduced the uptake of (15)NO3(-) and (15)NH4(+) from the medium and decreased the overall assimilation of these nitrogen sources into amino acids in roots and leaves. Root (15)NO3(-) assimilation was more affected by hypoxia than that of (15)NH4(+), resulting in enhanced nitrite and nitric oxide release in the solution. However, (15)NO3(-) was translocated in substantial amounts by xylem sap and considerable (15)NO3(-) assimilation into amino acids also occurred in the leaves, both under hypoxia and normoxia. By contrast, (15)NH4(+) assimilation occurred predominantly in roots, resulting in accumulation of mainly (15)N-alanine in this tissue during hypoxia. Analysis of lactate levels suggested higher fermentation in roots from NH4(+)-treated plants compared to the NO3(-) treatment. Thus, foliar NO3(-) assimilation may be relevant to plant tolerance to oxygen deficiency, since it would economize energy expenditure by hypoxic roots. Additionally, the involvement of nitric oxide synthesis from nitrite in the beneficial effect of NO3(-) is discussed.
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DOI:10.1016/s0031-9422(99)00545-2URLPMID:10724178 [本文引用: 1]
The content of free sugars and the activities of enzymes involved in carbon metabolism-sucrose synthase, acid and alkaline invertase, phosphoenol pyruvate carboxylase, malic enzyme and isocitrate dehydrogenase were determined during seed development in mungbean pods. A decrease in carbohydrate content of pod wall from 10 to 25 days after flowering (DAF) and a concomitant increase in the seed till 20 DAF was observed. Sucrose remained the dominant soluble sugar in the pod wall and seed. In the branch of inflorescence and pod wall, the activities of sucrose metabolizing enzymes, viz. acid and alkaline invertase, sucrose synthase (synthesis and cleavage) and sucrose phosphate synthase were higher at 5-10 DAF, whereas in seed the maximum activities of these enzymes were observed at the time of maximum seed filling stage (10-20 DAF). High activities of sucrose synthase at the time of rapid seed filling can be correlated to its sink strength. Higher activities of phosphoenol pyruvate carboxylase in the branch of inflorescence and pod wall than in seed may indicate the involvement of the fruiting structure for recapturing respired CO2. High activities of isocitrate dehydrogenase and malic enzyme in the seed at the time of rapid seed filling could provide NADPH and carbon skeletons required for the synthesis of various seed reserves.
DOI:10.1104/pp.46.2.299URLPMID:16657454 [本文引用: 1]
A number of enzymes presumably implicated in starch synthesis were assayed at various stages of endosperm development ranging from 8 days to 28 days after pollination. Activity for invertase, hexokinase, the glucose phosphate isomerases, the phosphoglucomutases, phosphorylase I, uridine diphosphate glucose pyrophosphorylase, and the starch granule-bound nucleoside diphosphate glucose-starch glucosyltransferase was present at the earliest stage of development (8 days) studied. Activity was detectable for phosphorylase III, the soluble adenosine diphosphate glucose-starch glucosyltransferase, adenosine diphosphate glucose pyrophosphorylase, and sucrose-uridine diphosphate glucosyltransferase at 12 days. For phosphorylase II and cytidine diphosphate glucose pyrophosphorylase, activity was first detectable at the 14- and 16-day stages, respectively. Rapid increases in starch content are observed prior to detectable activity for adenosine diphosphate glucose pyrophosphorylase, the soluble adenosine diphosphate glucose-starch glucosyltransferase and phosphorylases II and III. For all enzymes, except invertase, activity per endosperm rises to a peak at 22 or 28 days. Greatest activity for invertase is found at 12 days with a steady decline thereafter. The pattern of invertase activity in comparison with that of sucrose-uridine diphosphate glucosyltransferase supports previous suggestions, that the latter plays a key role in the conversion of sucrose to starch. In addition to phosphorylases I, II, and III, multiple forms of glucosephosphate isomerase and phosphoglucomutase were detected.
DOI:10.1007/s00253-014-6020-0URLPMID:25139449 [本文引用: 1]
When photosynthetic organisms are exposed to abiotic stress, their photosynthetic activity is significantly depressed. In particular, photosystem II (PSII) in the photosynthetic machinery is readily inactivated under strong light and this phenomenon is referred to as photoinhibition of PSII. Other types of abiotic stress act synergistically with light stress to accelerate photoinhibition. Recent studies of photoinhibition have revealed that light stress damages PSII directly, whereas other abiotic stresses act exclusively to inhibit the repair of PSII after light-induced damage (photodamage). Such inhibition of repair is associated with suppression, by reactive oxygen species (ROS), of the synthesis of proteins de novo and, in particular, of the D1 protein, and also with the reduced efficiency of repair under stress conditions. Gene-technological improvements in the tolerance of photosynthetic organisms to various abiotic stresses have been achieved via protection of the repair system from ROS and, also, by enhancing the efficiency of repair via facilitation of the turnover of the D1 protein in PSII. In this review, we summarize the current status of research on photoinhibition as it relates to the effects of abiotic stress and we discuss successful strategies that enhance the activity of the repair machinery. In addition, we propose several potential methods for activating the repair system by gene-technological methods.
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DOI:10.1111/j.1600-079X.2010.00847.xURLPMID:21244479 [本文引用: 1]
Melatonin (N-acetyl-5-hydroxytryptamine) is a pineal hormone widely known for its antioxidant properties, both in vivo and by direct capture of free radicals in vitro. Although some metabolites and oxidation products of melatonin have been identified, the molecular mechanism by which melatonin exerts its antioxidant properties has not been totally unravelled. This study investigated the reaction mechanism of oxidation of melatonin by radio-induced reactive oxygen species, generated by gamma radiolysis of water for aqueous solutions of melatonin (from 20 to 200 μm), in the presence or absence of molecular oxygen. The hydroxyl radical was found to be the unique species able to initiate the oxidation process, leading to three main products, e.g. N(1)-acetyl-N(2)-formyl-5-methoxykynurenin (AFMK), N(1)-acetyl-5-methoxykynurenin (AMK) and hydroxymelatonin (HO-MLT). The generation of AFMK and HO-MLT strongly depended on the presence of molecular oxygen in solution: AFMK was the major product in aerated solutions (84%), whereas HO-MLT was favoured in the absence of oxygen (86%). Concentrations of AMK remained quite low, and AMK was proposed to result from a chemical hydrolysis of AFMK in solution. A K-value of 1.1 × 10(-4) was calculated for this equilibrium. Both hydrogen peroxide and superoxide dismutase had no effect on the radio-induced oxidation of melatonin, in good accordance for the second case with the poor reactivity of the superoxide anion towards melatonin. Finally, a reaction mechanism was proposed for the oxidation of melatonin in vitro.
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DOI:10.3389/fpls.2017.00069URLPMID:28220130 [本文引用: 1]
Consequences of drought stress in crop production systems are perhaps more deleterious than other abiotic stresses under changing climatic scenarios. Regulations of physio-biochemical responses of plants under drought stress can be used as markers for drought stress tolerance in selection and breeding. The present study was conducted to appraise the performance of three different maize hybrids (Dong Dan 80, Wan Dan 13, and Run Nong 35) under well-watered, low, moderate and SD conditions maintained at 100, 80, 60, and 40% of field capacity, respectively. Compared with well-watered conditions, drought stress caused oxidative stress by excessive production of reactive oxygen species (ROS) which led to reduced growth and yield formation in all maize hybrids; nevertheless, negative effects of drought stress were more prominent in Run Nong 35. Drought-induced osmolyte accumulation and strong enzymatic and non-enzymatic defense systems prevented the severe damage in Dong Dan 80. Overall performance of all maize hybrids under drought stress was recorded as: Dong Dan 80 &gt; Wan Dan 13 &gt; Run Nong 35 with 6.39, 7.35, and 16.55% yield reductions. Consequently, these biochemical traits and differential physiological responses might be helpful to develop drought tolerance genotypes that can withstand water-deficit conditions with minimum yield losses.
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DOI:10.1016/j.plaphy.2016.05.038URLPMID:27269705 [本文引用: 1]
The application of nanostructured materials, designed for sustainable crop production, reduces nutrient losses, suppresses disease and enhances the yields. Nanomaterials (NMs), with a particle size less than 100?nm, influence key life events of the plants that include seed germination, seedling vigor, root initiation, growth and photosynthesis to flowering. Additionally, NMs have been implicated in the protection of plants against oxidative stress as they mimic the role of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX). However, besides their beneficial effects on plants, applications of NMs have been proved to be phytotoxic too as they enhance the generation of reactive oxygen species (ROS). The elevated level of ROS may damage the cellular membranes, proteins and nucleic acids. Therefore, in such a conflicting and ambiguous nature of NMs in plants, it is necessary to decipher the mechanism of cellular, biochemical and molecular protection render by NMs under stressful environmental conditions. This review systematically summarizes the role of NMs in plants under abiotic stresses such as drought, salt, temperature, metal, UV-B radiation and flooding. Furthermore, suitable strategies adopted by plants in presence of NMs under challenging environments are also being presented.
DOI:10.1007/s10725-015-0066-6URL [本文引用: 2]
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为研究大棚膜下滴灌灌溉上限与施肥量耦合对番茄光合、产量及水分利用效率的影响，以金鹏1号番茄为试材，按照二元二次正交旋转组合设计原理，建立了光合与产量指标的数学模型，分析了水肥两因子的耦合效应。试验结果表明，所建模型达到显著水平；水对光合的影响大于肥，对产量的影响小于肥，水肥对光合和产量的耦合分别存在显著的负效应和正效应；光合速率随灌溉上限的上升表现出明显的上升趋势，超过一定范围后开始下降；不论灌溉上限高低，光合速率均随施肥量的增加表现出先降低后升高的趋势，变化趋势缓慢；番茄的产量随灌溉上限和施肥定额的增加而显著增加，超过一定范围后产量逐渐降低。得出合理的灌溉施肥指标：灌溉下限为田间持水量的50%，灌溉上限为田间持水量的80%～82%，施肥N 313.75～439.75 kg/hm2、P2O5156.55～ 219.19 kg/hm2、K2O 313.75～439.75 kg/hm2。此时，番茄的产量达到124 t/hm2、水分利用效率达到43.2 kg/m3。
URL [本文引用: 1]
为研究大棚膜下滴灌灌溉上限与施肥量耦合对番茄光合、产量及水分利用效率的影响，以金鹏1号番茄为试材，按照二元二次正交旋转组合设计原理，建立了光合与产量指标的数学模型，分析了水肥两因子的耦合效应。试验结果表明，所建模型达到显著水平；水对光合的影响大于肥，对产量的影响小于肥，水肥对光合和产量的耦合分别存在显著的负效应和正效应；光合速率随灌溉上限的上升表现出明显的上升趋势，超过一定范围后开始下降；不论灌溉上限高低，光合速率均随施肥量的增加表现出先降低后升高的趋势，变化趋势缓慢；番茄的产量随灌溉上限和施肥定额的增加而显著增加，超过一定范围后产量逐渐降低。得出合理的灌溉施肥指标：灌溉下限为田间持水量的50%，灌溉上限为田间持水量的80%～82%，施肥N 313.75～439.75 kg/hm2、P2O5156.55～ 219.19 kg/hm2、K2O 313.75～439.75 kg/hm2。此时，番茄的产量达到124 t/hm2、水分利用效率达到43.2 kg/m3。
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DOI:10.1007/s11738-015-2045-yURL [本文引用: 2]
DOI:10.1093/jxb/eru392URLPMID:25297548 [本文引用: 2]
Melatonin is a well-known agent that plays multiple roles in animals. Its possible function in plants is less clear. In the present study, we tested the effect of melatonin (N-acetyl-5-methoxytryptamine) on soybean growth and development. Coating seeds with melatonin significantly promoted soybean growth as judged from leaf size and plant height. This enhancement was also observed in soybean production and their fatty acid content. Melatonin increased pod number and seed number, but not 100-seed weight. Melatonin also improved soybean tolerance to salt and drought stresses. Transcriptome analysis revealed that salt stress inhibited expressions of genes related to binding, oxidoreductase activity/process, and secondary metabolic processes. Melatonin up-regulated expressions of the genes inhibited by salt stress, and hence alleviated the inhibitory effects of salt stress on gene expressions. Further detailed analysis of the affected pathways documents that melatonin probably achieved its promotional roles in soybean through enhancement of genes involved in cell division, photosynthesis, carbohydrate metabolism, fatty acid biosynthesis, and ascorbate metabolism. Our results demonstrate that melatonin has significant potential for improvement of soybean growth and seed production. Further study should uncover more about the molecular mechanisms of melatonin's function in soybeans and other crops.
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DOI:10.1016/j.mib.2006.01.001URLPMID:16458044 [本文引用: 1]
The metabolism of carbon- and nitrogen-containing compounds is fundamental to all forms of life. To cope with changing environmental conditions, bacteria have to sense the nutrient supply and adapt their metabolism accordingly. In addition to nutrient- and pathway-specific responses, they integrate information from the different branches of metabolism to coordinate the control of the expression of many metabolic genes. Two major players interconnecting carbon and nitrogen regulation are the PII proteins and the phosphotransferase system. Moreover, several DNA-binding transcription regulators sense signals are derived from both carbon and nitrogen metabolism. The regulatory networks enable the bacteria to make the appropriate metabolic responses to changing nutrient availabilities in the environment.
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DOI:10.1016/j.envexpbot.2017.02.012URL [本文引用: 1]
