摘要:为了探讨供钾水平对胡麻抗倒伏特性的调节机理，以‘陇亚11号（V1）’和‘定亚23号（V2）’为材料，设不施钾[K0，0 kg（K2O）·hm-2]、低钾[K1，30 kg（K2O）·hm-2]、中钾[K2，60 kg（K2O）·hm-2]和高钾[K3，90 kg（K2O）·hm-2]4个供钾水平，共8个处理的裂区试验，分析不同供钾水平对胡麻茎秆木质素含量、木质素合成相关酶活性、茎秆力学特性和抗倒伏指数及产量的影响。结果表明，不同供钾水平，植株物理性状与倒伏的关系主要体现在青果期至成熟期，胡麻抗倒伏指数与茎粗呈显著正相关（P < 0.05），与株高和重心高度呈负相关。胡麻茎秆木质素含量随生育时期及供钾量不同而有所差异，苗期至盛花期，施钾后V1和V2木质素含量均在K2处理下较高；青果期至成熟期，K3处理下V1和V2木质素含量较K0处理平均显著增加17.68%和23.25%，其中，青果期不同品种、施钾及二者互作对木质素含量影响均达极显著水平（P < 0.01）。K2处理提高了现蕾期—青果期胡麻茎秆的苯丙氨酸解氨酶（PAL）活性及现蕾期V1品种酪氨酸解氨酶（TAL）活性，而K3处理提高了V2品种TAL活性；钾肥显著影响青果期胡麻茎秆肉桂醇脱氢酶（CAD）活性，2个品种CAD活性施钾较不施钾分别平均增高31.96%和12.09%；V1、V2品种过氧化物酶（POD）活性提升效应的适宜供钾量分别为K2、K1水平。V1品种茎秆抗折力和抗倒伏指数K2和K3处理较K0分别上升45.68%、48.90%和16.86%、31.92%，V2品种则分别上升84.32%、77.50%和1.89%、14.49%。相关分析表明，青果期，4种木质素合成相关酶与木质素和抗倒伏指数存在正相关。施钾后，2个品种均在K3处理下籽粒产量最高，分别较K0增产10.71%和17.77%，V1供钾处理间产量无显著差异，V2产量K2、K3处理较K0分别显著高出12.24%和17.77%。可见，品种是胡麻木质素积累进程中重要的影响因子，钾肥对木质素含量及其代谢相关酶活性具备一定的协同提升效应。在本试验及类似农田生态类型环境下，中、高供钾水平[60~90 kg（K2O）·hm-2]有利于促进胡麻茎秆木质素合成积累，有效地防止胡麻倒伏，为其高产稳产奠定一定基础。
关键词:胡麻/
供钾水平/
木质素/
抗倒伏特性/
籽粒产量
Abstract:To explore the effects of potassium supply on the lodging resistance of oil flax, split-plot experiments were conducted with the cultivars 'Longya No. 11' (V1) and 'Dingya No. 23' (V2) and four potassium (K2O) levels: no potassium[K0, 0 kg(K2O)·hm-2], low potassium[K1, 30 kg(K2O)·hm-2], medium potassium[K2, 60 kg(K2O)·hm-2], and high potassium[K3, 90 kg(K2O)·hm-2]. The lignin content, lignin synthesis-related enzyme activities, stem mechanical properties, lodging resistance index of the stem, and yield of oil flax under different potassium supply levels were analyzed. The results showed that under different potassium levels, the relationships between the plant physical characteristics and lodging were mainly observed from the green fruit stage to the maturation stage. The lodging resistance index of oil flax was significantly positively correlated with culm diameter and negatively correlated with plant height and gravity center height. The lignin content of the oil flax stems changed during the growth period and with the potassium supply. The lignin content of V1 and V2 was higher in K2 treatment after potassium application from the seedling stage to the flower stage. Compared with that under K0 treatment, the lignin content of V1 and V2 under K3 treatment increased by 17.68% and 23.25%, respectively, from the green fruit stage to the maturation stage. The effects of cultivar, potassium application, and their interactions on the lignin content at the green fruit stage reached extreme significance (P < 0.01). The K2 treatment increased the phenylalanine ammonia-lyase (PAL) activity of the stem from the budding stage to the green fruit stage and the tyrosine ammonia-lyase (TAL) activity of the V1 cultivar at the budding stage; the K3 treatment increased the TAL activity of the V2 cultivar. Potassium fertilizer significantly affected the cinnamon alcohol dehydrogenase (CAD) activity of the oil flax stem at the green fruit stage. Compared with that in the no potassium treatment, the CAD activity of two cultivars increased by 31.96% and 12.09% on average, respectively, after potassium application. K2 and K1 are the suitable potassium supply levels for peroxidase activity improvement in the V1 and V2 cultivars, respectively. Compared with the indexes at K0, the snapping resistance and lodging resistance indexes of V1 in the K2 and K3 treatments increased by 45.68% and 48.90%, respectively, and by 16.86% and 31.92%, respectively; V2 snapping resistance increased by 84.32% (K2) and 77.50% (K3), respectively, and the lodging resistance index increased by 1.89% (K2) and 14.49% (K3), respectively. Correlation analysis showed that the four lignin related enzymes were positively correlated with lignin content and lodging resistance index at the green fruit stage. After potassium application, the highest grain yield was observed in the K3 treatment, which increased by 10.71% for V1 and by 17.77% for V2 compared with that in the K0 treatment. There was no significant difference in the yield of V1 among different potassium levels. However, the yields of V2 in the K2 and K3 treatments were significantly higher by 12.24% and 17.77%, respectively compared with that of K0. These results indicate that the cultivar is an important influencing factor of the lignin accumulation process of oil flax and that potassium fertilizer has a synergistic promotional effect on the lignin content and the metabolism-related enzyme activities. In this experiment site and the farmlands with similar ecological environments, the use of medium and high potassium fertilizers[60-90 kg(K2O)·hm-2] promotes the synthesis and accumulation of oil flax stem lignin, prevents oil flax lodging, and establishes a foundation for a high and stable yield.
Key words:Oil flax/
Potassium supply level/
Lignin/
Lodging resistance/
Grain yield
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