水分调控滴灌甜菜碳水化合物积累转化机理研究

The application of drip irrigation technique makes sugar beet get compensation effect of water deficit. This project intends to use "water-saving and crop quality improvement effect of deficit irrigation" as its researching main line, to identify the regulation effects of soil moisture on root morphological and structure characters, carbohydrates accumulation, root sourced signal, sugar metabolism-relative enzyme and root quality of drip irrigated sugar beet by using field experiment and C isotope tracing. Two sugar beet genotypes were chosen in the experiment, and are typical beets grown in Xinjiang. The interactive coupling relationship between root structure and carbohydrates accumulation of sugar beet were explored in order to achieve sugar metabolism mechanism on condition of water deficit compensatory and then to provide initial and terminal signal of root sugar accumulation and their main control factors for taking effective regulating measures in quality improvement of drip irrigated sugar beet in arid area.

滴灌技术的推广应用使得甜菜缺水补偿效应得到发挥，针对亏缺灌溉下滴灌甜菜节水调质机理不明确的问题，选取丰产和高糖两个基因型甜菜材料，通过小区控制试验和碳同位素管栽试验，结合现代植物细胞学、植物生理与同位素示踪技术，明确亏缺灌溉对滴灌甜菜块根形态结构、碳水化合物累积、根源信号以及糖代谢相关酶活性的影响，揭示土壤水分与甜菜块根结构及块根碳水化合物积累的耦合关系，阐明亏缺灌溉下甜菜块根糖代谢机理，提出水分亏缺补偿效应下块根糖分积累的起始与结束信号及其主控因子，为进一步提升滴灌甜菜品质提供基础理论和技术支持。

新疆干旱区作物生长过程中缺水环境重复发生，针对甜菜阶段性耐旱特性不明确的问题，项目基于干旱区膜下滴灌技术，研究调亏灌溉条件下土壤水分与甜菜块根结构及块根碳水化合物积累的耦合关系，阐明亏缺灌溉下甜菜块根糖代谢机理。结果表明，叶丛期调亏灌溉显著影响甜菜同化物积累与分配，甜菜通过降低叶片数量和光合速率、地下部分库容和侧根密度来适应叶丛期缺水，恢复供水后叶片光合作用和库容均有不同程度的增加，中度调亏灌溉处理不降低同化物的基础上提高其向块根的分配量，甜菜深层（20-40cm）侧根直径增加；重度调亏灌溉处理降低同化物的基础上提高其向叶片的分配量，甜菜近地表（0-10cm）侧根表面积增加。中度调亏灌溉显著提高块根SS、降低SPS活性，重度调亏灌溉抑制块根SS和SPS活性，恢复供水后中度和重度调亏灌溉处理块根SS和SPS活性恢复至对照水平，而INV活性急剧降低。受到干旱刺激后块根中激素信号以及蔗糖信号响应迅速,块根中茉莉酸类化合物的合成随着调亏程度增加而增加，同时块根中LOX2S、AOS、AOC、OPR、JAZ、MYC2基因上调。受旱后块根中INV基因促进蔗糖分解进行渗透调节，与茉莉酸类化合物共同影响块根生长和蔗糖含量。研究结果揭示了滴灌甜菜块根应对不同调亏程度的响应机制，进一步提升甜菜耐旱生理特性提供支持。