棉花营养液漂浮育苗条件下棉幼苗根系生长动态

Root Growth Dynamic of Cotton Seedling by Floating Nursing Seeding in Nutrient Water-bed in the Field

以金农棉1号F1为材料,在营养液漂浮育苗条件下,研究了不同播种深度(1,2,3,4 cm)棉苗根系的生长动态。结果表明:种子破胸播种后16 h主根开始伸长,24 h后伸长可达3～5 mm,第3天后主根上有一级侧根原基突起,第4天突起明显,部分突起伸长,出现3～5条一级侧根,第9天在一级侧根上长出二级侧根;不同播种深度之间根系生长有一定的差异,以播种深度为1,2 cm的处理根系生长较好,主根长度和一级侧根数均呈S型曲线增长;播种深度为3,4 cm的处理,根系生长发育不正常,特别是播种深度为4 cm的处理,播种后21d根系全部腐烂,棉苗死亡。

（the root growth dynamic of cotton seedling by Floating Nursing Seeding in Nutrient Water-bed were conducted in artificial climate chamber from 2010 to 2011.） F1 hybrid of Jinnongmian 1 were used as experimental variety and four different sowing depth including 1cm, 2cm, 3cm, 4cm were set in this study. The result indicates that the taproot elongated around 16 hours after sowing and its length got to from 3cm to 5cm after 24 hours. The root primordium can not observed outside of the cambial layer of the taproot at 2 DAS （days after sowing）. However, it is apparent on 3 DAS, some of them extended and 3 to 5 first lateral roots were formed, moreover, the secondary lateral root were formed on 9 DAS. This study also showed that the sowing depth had a significant influence on the growth of cotton root system. The root system developed very well with lcm and 2 cm sowing depth and both taproot length and first lateral roots amount increased according to S-curve growth model. While the root system with 3 cm and 4 cm sowing depth developed abnormally, especially these roots with 4 cm sowing depth rotted and the seedling died on 21 DAS.