在全球气候变暖的背景下，干旱已成为对作物产量构成威胁的主要自然灾害。大豆是主栽作物中需水最多且根系不发达的作物，常常因为干旱造成减产。发达的根系是作物抗旱的重要基础，而侧根建成对根系的发育至关重要。项目组研究发现，化控技术能够促根壮苗提高抗旱性。烯效唑（S3307）是生产上最常用的调节剂。本研究针对大豆苗期经常遇到的干旱问题，选用耐旱品种和干旱敏感品种为材料，采用“垂直板断水法”研究干旱胁迫条件下S3307浸种对不同基因型大豆苗期侧根建成的调控效应及机制，分别从根系形态结构、内源激素、细胞质膜透性、渗透调节物质、抗氧化酶活性及抗旱基因表达方面开展多方位研究，旨在全面系统揭示S3307壮苗及提高抗旱性的机理。深入研究根系建成及抗旱基因表达量的动态变化，在RNA水平上揭示调节剂作用的调控靶点，以探明调节剂提高大豆抗旱性的分子机理，从而拓宽化控技术作用机理的研究空间，并为化控技术应用提供依据。

Under the background of global warming, drought has become a threat major natural disasters to crop yield. Soybean is maximum water demand crop in main cultivation crops for its not developed root system, always has been caused yield loss by water deficit.Developed root system is an important foundation for crop drought resistance, while lateral root formation is critical to the root system development. Our research team found that chemical control technique could improve drought resistance by promoting root and invigorating seedlings. Uniconazole (S3307) is one of the most commonly used plant growth regulators in crop production.This study focuses on drought problems soybean seedling often encountered, Choose drought-resistant cultivars and drought sensitive cultivars as materials, use planting in papers sticked on vertical glass，under hydroponic condition to grow soybean method，and to stop water supply from VC stage，to research response of different genotype soybean seedling root formation and physiological metabolism by seed soaked S3307 under drought stress，from root morphology structure, endogenous hormone, key drought related enzymes, osmoregulation substances to reveal the mechanism of chemical control technique improve drought resistance and promoting root and invigorating seedlings. to further study on the dynamic expression amount changes of gene related to root formation and drought resistance, to reveal the control target of regulators at the RNA level, to proven molecular mechanism of regulator improving soybean drought resistance，To broaden research space of regulators applying mechanism, and to provide scientific basis for the application of chemical control technique.