大豆根系生长与花荚形成的关系研究

The flowers and pods of soybean evolved during rapid growth of root, stem and leaf of soybean, accompanied with part of the flower and pod abscission, effectual pod numbers per unit area were most important factors to decide the yield. Effect of root on the yield formation, and it was mainly effect by the formation process of flower and pod to realize. In the past, the research of root of soybean was limited to correlation analysis on relationship of morphological and physiological characteristics of the root and yield, it was not clear that the process of root establishing and flowers and pods formation. This project will compare with their different that soybean of super high yield (6.0 toha-1) and high-yield (4.5-5.25 toha-1) of 0-60cm soil layers on dry root weight, long lateral roots, root activity and internal hormone content and root nodules and so on for soybean root in the bleeding sap by varieties, density and nitrogen fertilizer in the field; compare with their nitrogen content and starch contents of leaf area, photosynthetic rate, leaf area index, leaf, petiole and internal hormone content and so on in stem; and compared with their dynamics changes of flowers and pods formation and loss for the soybean plant of super high yield and high-yield. Explore the root growth of soybean with the dynamic of flowering and podding with the relationship of effectual flowers and pods numbers, to proven the physiological mechanism of root growth on the formation of flowers and pods, to reveal formation regulation of yield (about 6.0 toha-1) of mid-maturation soybean root, and to provides a theoretical basis for super high-yielding soybean breeding and cultivation.

大豆花荚在根、茎、叶的快速生长过程中逐渐形成并绝大部分脱落。单位面积成荚数是影响产量高低的最重要因素，根系对产量形成的影响主要是通过影响花荚形成过程实现的。以往大豆根系研究多局限于根系形态生理性状与产量关系的相关分析。根系建成过程与花荚形成和脱落过程的关系不清楚。本项目通过品种、密度和氮肥田间试验，比较超高产（近6.0t/hm2）与高产（4.5-5.25t/hm2）大豆0-60cm土层根干重密度、侧根长密度、根系活性，以及根系伤流液中內源激素含量、根瘤数等；比较超高产与高产大豆植株各茎节叶面积、光合速率、叶面积指数、叶片和叶柄含氮量及淀粉含量、茎內源激素含量等；比较超高产与高产大豆植株花荚形成和脱落动态。探索大豆根系生长与开花、结荚动态和成花数、成荚数的关系，探明根系生长对花、荚形成影响的生理机制，揭示中熟大豆近6.0t/hm2产量根系的建成规律。为大豆超高产育种和栽培调控提供理论依据。

近年，在新疆沙湾县乌兰乌苏镇小庙村创造了全国春大豆高产纪录（6321kg·hm-2）。大豆产量高低主要是由单位面积粒数决定的，而花数、荚数多和腔数多是粒数多的前提条件。大豆超高产首先要有足够的总花数、总荚数和总腔数，为获得足够的总粒数奠定基础。在大豆地上各茎节陆续开花、结荚的同时，根系也快速生长，表现根量迅速增大和深扎，根干重、侧根长度在始粒期前后达峰值。大豆根系生长与花荚形成的关系缺乏深入研究。本项目在新疆伊宁县（主产区）采用田间试验比较了中熟（生育期约120天）大豆品种、密度、施氮量处理间0～80cm土层根干重密度、侧根长密度、根系活性、根瘤数等与花荚形成的关系。结果表明：超高产田（近6000kg·hm-2）在花、荚期根系伤流量、0～80 cm土层总根干重、0～40 cm根系活性、总花数、总腔数均明显高于高产田（近5250kg·hm-2）；花期根干重增量、伤流势与总花数正相关，R2值分别为0.970*和0.898*；花荚期根干重增量、伤流势与总荚数正相关，R2值分别为0.905*和0.77*；密度、施氮量、灌水量试验的结果与此相似。施氮肥延长大豆开花期，增加单位面积总花数，主要是增加13-18节花数的结果、推迟始荚期，延长结荚期，增加荚数和总腔数；增加密度推迟大豆开花和结荚高峰出现时间，结荚期后移，增加单位面积的总花数、总荚数、总腔数、总粒数、产量。适宜种植密度、施氮量、灌水量增产的重要原因是促进大豆根系生长，进而增加花数、荚数、腔数、粒数的结果。中熟春大豆品种获得近6 000 kg·hm-2 产量，始粒期0～80 cm土层根系总干重为125～142.3 g·m-2，总花数3 448. 4～3 695.7×104朵·hm-2、总腔数2 767.4～3 303.8×104个·hm-2、总粒数2 444.4～2685.9×104个·hm-2。在本试验条件下，促进花荚期根系快速生长，增加根系总干重、总根长和分布深度是增加总花数、总荚数、总腔数及总粒数,获得大豆产量近6000kg·hm-2的重要途径。