垂向分根区灌溉对硫代葡萄糖苷的调控机制

Glucosinolates are a group of secondary plant metabolites mainly found in the Brassicaceae family. The hydrolysis products of certain glucosinolates have been reported to bear strong anti carcinogenic properties. Therefore, interest has grown on producing vegetables with increased glucosinolate. Deficit irrigation combined with appropriate nutrients application can largely increase glucosinolate concentration, however, this is usually accompanied by yield loss. In this study, a vertical partial rootzone drying system will be used to systematically study topsoil drying effect on glucosinolate biosynthesis. To reveal the metabolism of glucosinolate in plant leaves, the plants were designed to suffer topsoil drying and wetting several times. And use 15N technique to investigate the glucosinolates biosynthesis, breakdown, and transfer in plant by determining glucosinolates concentration which containing 15N. Also, using vertical partial rootzone drying system to reduce plant water stress, focus on determining plant hormone effect on glucosinolate metabolism. Select appropriate hormone which related to glucosinolate biosynthesis under drought stress, to apply the foliar spray. Leaf RNA will be extracted at different time after spraying. Expression gene related to glucosinolate metabolism will be quantified by real-time PCR to demonstrate the regulation of drought stress on glucosinolate biosynthesis. These results are of great importance to develop agronomic strategies to get improved glucosinolates in targeted vegetables.

硫代葡萄糖苷（硫苷）主要存在于十字花科植物中，其代谢产物能有效预防癌症的发生。因此在种植过程中促进该类蔬菜中硫苷合成已成为研究热点。亏缺灌溉能有效提高蔬菜中硫苷浓度，但都导致生物量显著下降。针对该方法不足，本项目运用垂向分根区灌溉技术，就干旱胁迫对硫苷合成的调控机制展开深入研究。对植物上层根区进行一次或多次干湿交替灌溉处理，采用15N追踪方法，通过检测植物不同器官中含15N的硫苷浓度，揭示干旱胁迫时硫苷在植物体内的合成、分解和转移过程。同时，采用分根区灌溉的方式将水分胁迫降到最低，集中研究植物内源激素与硫苷合成的关系。通过盆栽试验选取干旱胁迫时与抗逆相关的植物激素进行外源喷施，用RT-PCR方法检测硫苷合成相关基因的表达，揭示干旱胁迫时硫苷合成与植物内源激素的联系，综合分析干旱胁迫对硫苷的调控机制。此研究将为今后改进种植方式、提高蔬菜品质提供理论基础和科学依据。

水是生命之源，在全球变暖的大背景下，极端天气气候事件不断发生，表现为一部分地区洪涝频发、同时伴随着另外一些地区水资源匮乏，对社会稳定及生产发展的造成了严重影响。对于水资源暂时或永久性受限的地区，亏缺灌溉能够有效提高植物体硫苷浓度，但都导致生物量显著下降。针对该方法的不足，本项目运用垂向分根区灌溉技术，就干旱胁迫对植物体内硫苷合成的调控机制展开深入研究。结果表明，采取分根区灌溉这一方式，植物的抗旱耐受力相对于非分根区灌溉处理显著提高，主要表现在植物的地上部鲜重，干重以及根部鲜重干重均显著提高。同时发现，经过分根区灌溉后，在干旱土壤条件下，植物体内的氮，硫，钾营养元素均高于正常灌溉的处理。通过测定硫代葡萄糖苷的含量变化发现低硫土壤中，区别不显著。在高硫处理土壤中，植物地上部硫代葡萄糖苷的浓度显著高于普通灌溉的植物。另一方面，极端暴雨的频繁发生引发城市洪涝问题，同时暴雨作为载体携带大量的营养物质进行迁移转化，进而引发生态环境恶化问题。利用模型进行数值模拟是研究暴雨径流管理和生态防治的重要手段。结果表明，随着雨量的增大，营养物质负荷总量明显增大，营养物质负荷削减率降低较为明显。当降雨量增加1-3倍时，营养物质负荷总量增加了0.7-2.5倍，营养物质负荷削减率降低了0.04-0.1倍。