微钵育苗不同苗龄移栽的棉苗生长发育特点

Characteristics of Growth and Development of Cotton with Different Seedling Ages Raised in Small Nutritional Pot

通过微钵育苗不同苗龄移栽期试验,研究不同苗龄棉苗移栽后成活率及生长发育特点。结果表明,微钵育苗15 d、20 d和25 d苗龄处理的移栽成活率均在97.1%以上,苗龄30 d处理移栽成活率下降。微钵育苗20 d苗龄处理棉苗干重积累适宜,移栽后14 d地上、地下部生长转化快;25 d苗龄处理棉苗与20d苗龄处理相比,根系干重增长缓慢,移栽后14 d地上部叶与茎干重均为负增长;苗龄短(15 d)棉苗干重积累少,但移栽后生长转化也很快,苗龄长(30 d)棉苗干重积累多但移栽后生长转化慢,可见25 d苗龄是棉苗移栽后生长转化变慢的转折期。20d和25 d苗龄处理棉苗营养生长和生殖生长协调,最终产量水平高;15 d苗龄处理移栽后在持续高温条件下营养过旺,造成生殖生长迟且弱,苗龄30 d处理产量也低于20 d和25 d苗龄处理。可见,微钵育苗适龄移栽是提高移栽成活和获得高产的关键措施之一。

The experiment of seedling raised in small nutritional pot was conducted in field with different transplanting date. The purpose was to investigate the survival rate and growth of seedlings with different ages. The results were as follows： The survival rate after transplanting was up to 97.1% for seedlings at 15 d, 20 d and 25 d age, and declined at 30 d age. For the seedlings at 20 d age, the dry matter weight was moderate and the growth rate was high at the 14th day after transplanting. For the seedling at 20 d age,the root weight was low and the growth rate of above-ground organs was negative at the 14th day after transplanting,compared to the seedling at 15 d age. The seedlings of 15 d age were less in dry matter and had a higher growth rate at the 14th day after transplanting,while the situation for the seedlings at 30 d age was in reverse. Therefore, 25 d of seedling age was the turning point at which the growth rate for seedling turned slow. It was coordination with vegetative and reproductive organs for seedlings at 20 d or 25 d, and correspondingly, the yields were high. The reproductive growth was weak and late for the seedlings at 15 d for its uncoordinated growth between vegetative and reproductive organs. The yield of seedlings at 30 d age was lower than that at 20 d or 25 d. The results demonstrated that the appropriate seedling age is important for growth and yield for seedling raised in small nutritional pot.