摘要:单一耕作制度和作物品种，使设施连作障碍日益加剧。番茄和秋葵都是重要的设施蔬菜类型，但种植发现秋葵对番茄存在生长障碍，研究秋葵对番茄的生长障碍发生的生理生态机制具有重要意义。本研究选取种植秋葵的1 a和10 a土壤浸提液（简称1 a浸提液和10 a浸提液），以全素营养液为对照（简称CK），探讨秋葵连作土壤浸提液对番茄萌发期种子和幼苗生长的影响。结果表明：同一浓度土壤浸提液处理下，10 a浸提液的番茄萌芽期种子表现出主根畸形，侧根增多但细弱；番茄幼苗分根增多，根系活性低于1 a浸提液且都显著低于CK，顶部嫩叶失绿异常，活性氧代谢系统紊乱。同一年限不同秋葵土壤浸提液浓度处理下，番茄萌发期种子随浸提液浓度的升高表现出主根畸形，侧根增多且细弱，番茄幼苗分根增多，1 a和10 a浸提液的番茄根尖数、分根数分别最高达1 146、3 321和2 291、1 947，显著高于对照（1 071、385）；秋葵土壤浸提液浓度高于250 mg·mL-1处理下番茄幼苗根系活性都显著低于CK，顶部嫩叶失绿异常，活性氧代谢系统紊乱。研究表明秋葵根系物及分泌物在土壤中残留，对后茬番茄的生长造成不良影响，这些物质随种植年限增加而富集，从而对番茄产生更严重的毒害。
关键词:番茄/
秋葵/
土壤浸提液/
连作障碍/
轮作/
化感作用
Abstract:Single tillage system, single variety and excessive pursuit for economic efficiency have exacerbated the barriers of continuous cropping of greenhouse tomato (Lycopersicum esculentum). Although its root secretions can cause autotoxicity, okra (Hibiscus esculentus) is a new vegetable with great economic prospect in China. Rotation is an effective way to avoid continuous cropping obstacles, however, in practice, rotation of tomato and okra inhibited growth and impeded fruiting of tomato. To clear the hypotrophy between tomato and okra, soils of okra continuously cropped for 1 year and 10 years were used to conduct an experiment with tomato seeds and seedlings. Water extracts of two soils were diluted into 1 000 mg·mL-1, 2 000 mg·mL-1 and 3 000 mg·mL-1 to treat tomato seeds, and into 125 mg·mL-1, 250 mg·mL-1 and 500 mg·mL-1 to cultivate tomato seedlings. Physiological and biochemical analysis and seed root and stem morphology observation of tomato were conducted to investigate the influence on the below-ground and above-ground growth of tomato to determine the effects of okra soil extracts on tomato seed germination and seedling growth. The results showed that under the same concentration of soil extract, with continuous cropping years increase, the main root of tomato deformed with more but thin lateral root. Tomato seedling also showed increased root forks and root activity significantly lowered and with abnormal and green-lost top leaves compared to the control (total nutrient solution, CK) treatment. The activity of antioxidant enzyme, and MDA and proline contents were also significantly different from CK. Under different concentrations of soil abstracts for the same continuous cropping year, main root deformity appeared gradually in germinated tomato seeds as the concentration of soil extract increased. Also lateral roots increased and most relatively thin, tomato seedling rootlets increased and root tip number and rootlets were respectively 1 146 and 3 321 for the 1-year and 2 291 and 1 947 for the 10-year continuous cropping, all significantly higher than those under the control (1 071 and 385, respectively). Root activity of tomato seedlings firstly rose and then fell. At 3 days of cultivation, root activity of tomato seedlings under soil abstracts with over 250 mg·mL-1 concentration of 1 year and 10 years continuous cropping were lower than that of CK. Antioxidant enzyme activity, MDA and proline contents were also significantly different from CK. Above all, some allelechemicals were secreted by okra roots, including the substances vestigital in the soil, which had negative effects on subsequent tomatoes. The substances were enriched with increasing years of continuous cropping, which caused more damage to succeeding tomato crops.
Key words:Tomato/
Okra/
Soil extract/
Continuous cropping obstacle/
Rotation/
Allelopathy
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