华北地区年雨量约有70%以上降于6、7、8三个月,某些年份有50%以上的年雨量降于7月下旬到8月上旬或中旬期间,这时期内正当棉株开花盛期,脱落常较严重,多阴雨、光照强度低可能为当时影响脱落的一个重要的外界条件因子。本试验的目的在于了解光线强度对于棉株现蕾开花以及落蕾落铃的影响,遮光试验特别集中在棉株开花期间。 About 70% of the annual rainfall in North China dropped to 6,7,8 for three months. In some years, more than 50% of the annual rainfall dropped from late July to early August or mid-August. During this period, cotton plants were flowering Sheng, shedding often more serious, more rain, light intensity may be the impact of shedding an important external conditions factor. The purpose of this experiment is to understand the effects of light intensity on the flowering of cotton plants and the falling and falling bell. The shading test is especially focused on the flowering of cotton plants.