淹水直播稻萌发期生长和贮藏物质分解对外源GAs的响应

Responses of Growth and Storage Material Decomposition to Exogenous GAs in Submerged Direct Seeding Rice during Germination

摘要: 为研究外源赤霉素(GAs)对水直播模式下稻种淹水萌发能力的调控效应，本试验以淹水敏感型水稻“川优6203”为试验材料，稻种分别于0、10、100、1000 mg/L GAs溶液浸种24 h后，分别进行0、3、7、14 d淹水处理，并以常规湿直播作为对照，分析外源GAs对稻种萌发、株高伸长、植株贮藏物质消耗的影响。结果表明：长期淹水导致稻种淹水发芽率、株高及其日均伸长速率大幅降低，干物质量、可溶性糖、淀粉含量快速消耗。外源GAs处理可有效促进稻种淹水萌发和株高伸长，且100 mg/L GAs处理中淹水发芽率较其他处理提高30%以上，株高和日均伸长速率提高17.0%~30.7%，处理间差异显著(P < 0.05)。此外，经7 d以上淹水处理后，100 mg/L GAs处理植株干物质量、淀粉浓度和非结构碳水化合物(NSC)含量均显著高于其它处理，而其日均干物质消耗速率、可溶性糖含量均显著低于其它处理。由此可见，100 mg/L GAs外源处理稻种可通过抑制稻种过量的淀粉及干物质无氧损耗，有效促进水稻萌发及株高伸长，提升稻种耐淹能力。100 mg/L GAs可作为直播稻促耐淹生长调节剂的主要成分及最适浓度，这可为水直播促耐淹调控技术研发提供理论依据。

Abstract: In order to study the regulatory effect of exogenous gibberellins (GAs) on the germination ability of rice seeds in submerged direct seeding mode, the submergence-sensitive rice “Chuanyou 6203” was used as the experimental material in this experiment. After soaking the seeds in 100 and 1000 mg/L GAs solution for 24 h, they were submerged for 0, 3, 7, and 14 d respectively, and the conventional wet direct seeding was used as the control to analyze the effect of exogenous GAs on rice seed germination and plant height elongation, the effect of plant storage material consumption. The results showed that the germination rate, plant height and average daily elongation rate of rice seeds were greatly reduced due to long-term submergence, and the dry matter mass, soluble sugar and starch content were rapidly consumed. The exogenous GAs treatment can effectively promote the submerged germination and plant height elongation of rice seeds, and the submerged germination rate of the 100 mg/L GAs treatment increased by more than 30% compared with other treatments, and the plant height and the average daily elongation rate increased by 17.0%~ 30.7%, with significant difference between treatments (P < 0.05). In addition, after more than 7 days of submergence treatment, the dry matter mass, starch concentration and non-structural carbohydrate (NSC) content of plants in the 100 mg/L GAs treatment were significantly higher than those in other treatments, while the average daily dry matter consumption rate, Soluble sugar content was significantly lower than other treatments. It can be seen that exogenous treatment of rice seeds with 100 mg/L GAs can effectively promote rice germination and plant height elongation by inhibiting excessive starch and anaerobic loss of dry matter in rice seeds, and improve the submergence tolerance of rice seeds. 100 mg/L GAs can be used as the main component and optimum concentration of the submergence-tolerance-promoting growth regulator for direct seeding rice, which can provide a theoretical basis for the research and development of submergence-tole- rance regulation technology for direct seeding.