外源赤霉素调控胡椒花穗形成及增产机理

Exogenous Gibberellin Regulating Inflorescence Formation and Stimulation Yield Mechanism of Black Pepper

花穗数目是影响胡椒产量的关键因素之一,前人研究发现喷施赤霉素可以增加胡椒花穗数目,但是增穗机理尚不明确。为了揭示赤霉素调控植物由营养生长向生殖生长转变的机理,选用幼龄胡椒为试材,设置不同浓度赤霉素(20、40、60、100 mg/L)和赤霉素抑制剂多效唑(1500 mg/L),以清水为对照,进行喷施试验。研究测定胡椒的产量、花量,叶片的形态、光合生理、糖类物质含量、糖代谢相关酶活性。结果表明,外源赤霉素浓度为60 mg/L时,胡椒产量相对于对照显著提高了1.46倍,花穗数目增加了1.26倍。分析花穗数目增加的原因,发现喷施60 mg/L赤霉素提高了胡椒叶面积、促进了胡椒叶片光合作用,这有利于源器官碳水化合物含量的增加,该处理还促使碳水化合物向源叶中的淀粉分配,降低叶片蔗糖淀粉比。海藻糖代谢的反馈调控可能是促使碳水化合物向淀粉分配的原因之一,淀粉合成酶活性显著增加可能是促使淀粉累积的又一原因,所以,喷施赤霉素可以适度降低胡椒叶片海藻糖含量,提升淀粉合成酶活性,使淀粉累积实现促花。研究结果为生产中采用适当的技术措施促进成穗,获取高产胡椒提供实用的理论指导,同时也有助于拓展赤霉素在农业生产中的应用领域。

Inflorescence quantity is one of the key factors affecting pepper yield.Previous studies have found that gibberellin spraying can increase pepper inflorescence quantity,but the mechanism of inflorescence quantity increase is still unclear.To reveal the mechanism of gibberellin regulating the transition from vegetative growth to reproductive growth,in this study,young pepper was selected as the test material,with the treatment of spraying clear water as CK,different concentrations of gibberellin(20,40,60,100 mg/L)and gibberellin inhibitor paclobutrazol(1500 mg/L).The yield,inflorescence quantity,leaf morphology,photosynthetic physiology,carbohydrate content and enzyme activity related to sugar metabolism of pepper were measured.The results showed that when the concentration of exogenous gibberellin was 60 mg/L,the yield of pepper increased by 1.46 times compared with that of the control group,and inflorescence quantity increased by 1.26 times.The reasons for the increase in inflorescence quantity were analyzed and found that spraying 60 mg/L of gibberellin improved the pepper leaf area,promoted the pepper leaf photosynthesis,it was beneficial to the increase of the content of carbohydrate source organs.The treatment also promoted carbohydrate distribution to the starch in the source leaves,reducing the sucrose to starch ratio in the leaves.The feedback regulation of trehalose metabolism may be one of the reasons to promote carbohydrate distribution to starch,and the significant increase of starch synthase activity may be another reason to promote starch accumulation.Therefore,the application of gibberellin can moderately reduce trehalose content and increase starch synthase activity in pepper leaves and promote starch accumulation to increase inflorescence.The results of this study would provide practical theoretical guidance for the adoption of appropriate technical measures to promote inflorescence formation and obtain high yield pepper in production,and also help to expand the application field of gibberellin in agricultural production.