水稻发生贪青的原因和防止途径探讨

 叶色明显恋青、千粒重下降、空秕谷增加是贪青水稻的三个基本特征。影响水稻贪青的因素主要有三点：群体水平、叶片含氮率和灌浆期间的日辐射量大小。水稻贪青多数在群体过大、叶氮偏高的情况下发生。日辐射量较小时贪青加重。发生贪青的机理在于抽穗后光合产物在营养器官中滞留和植株呼吸消耗量明显增大，由此而引起穗部营养物质的严重贫缺，而发生贪青。以群体指数--实粒数曲线的转折点作为高产稻与贪青稻的界限，以曲线转折时的群体指数作为开始发生贪青的指标，可用于栽培实践，并就防止贪青的途径作了探讨。

THE CAUSE OF RICE OVER-GREEN GROWTH AND THE WAY OF PREVENTION

The leaf over-green, the low weight per 1000 grains and the high rate of empty grains, are the main characters of the over-green growth of rice, which are caused by three factors: population density, the N content in the leaves and the day-time radiation intensity at milking stage. The rice over,-green growth mostly occurs when a population is too high the N content is excessive, and low light intensity would aggravate the leaf over-green. The machanism of the leaf over-green growth is that photosynthate stagnates in vegetative organs afdter heading stage and the consumption by respiration excesses the assimilation, resulting in serious shortage of nourishment in the young panicles to produce the high rate of empty grains.It is practical for high yield cultivation by taking the population index i.e. the turning point of the full grains curve as a guiding line for high yield rice and the overgreen growth, and using the turning point of the population index curve as the indicator of the over-green growth. The ways of avoiding over-green growth are also dis scussed.