覆膜栽培对甘薯幼根生长发育、块根形成及产量的影响

Effects of Plastic Film Mulching Cultivation on Young Roots Growth Development, Tuber Formation and Tuber Yield of Sweet Potato

选用济徐23为材料,进行2年的大田试验和一年的盆栽试验,研究2种覆膜栽培对甘薯生长前期幼根生长发育和吸收能力、分化根内源激素含量和封垄期单株块根鲜重的影响及其与产量的关系。结果表明,覆黑色膜和覆透明膜处理与对照相比,均显著(P<0.05)增加甘薯秧苗栽植后10 d和20 d的幼根数量、总长度、鲜重、表面积、体积和幼根根系的吸收面积、活跃吸收面积,其中的幼根数量、鲜重、体积、幼根根系的吸收面积、活跃吸收面积在2种覆膜处理间差异显著(P<0.05),覆黑色膜优于覆透明膜;2种覆膜处理显著(P<0.05)提高秧苗栽植后10 d的根系活力,且覆黑色膜优于覆透明膜。同时,在块根分化期(秧苗栽植后20 d和30 d)2种覆膜处理显著(P<0.05)提高了分化根的ZR含量,促进初生形成层的活动和块根形成;在块根膨大初期(秧苗栽植后40 d)2种覆膜处理显著(P<0.05)提高分化根的ABA含量和显著(P<0.05)降低分化根的GA含量,促进次生形成层的活动、淀粉积累和块根膨大,其中,块根膨大初期2种覆膜处理ABA和GA含量差异显著(P<0.05),均覆黑色膜处理效果最好。在2年的大田试验中,2种覆膜处理与对照相比,均显著提高了甘薯封垄期的单株有效薯块数和单薯鲜重,覆黑色膜的单株有效薯块数高于覆透明膜,而覆透明膜的单薯鲜重显著(P<0.05)大于覆黑色膜处理。覆黑色膜和覆透明膜处理2011年分别增产10.71%和5.76%,2012年分别增产12.99%和7.45%。

A two-year trial and a one-year pot experiment were performed to investigate growth and development and absorbing ability of young roots, endogenous hormones content of differentiated roots at early growing stage using variety Jixu 23 with two types of plastic film mulching cultivation, and no plastic as control （CK）. The tuberous root fresh weight per plant at 50 days after planting was determined, and its relationship with tuberous root yield at harvest time was analyzed. The results showed that, at 10 and 20 days after planting, the number, total length, fresh weight, and volume of young roots significantly increased compared with control, and the differences in activity, total absorption area and active absorption area of young roots between two plastic film mulching treatments were significant （P〈0.05）, showing the black plastic film mulching （BF） superior to the transparent film mulching （TF）. Besides, zeatin riboside （ZR） content of differentiated roots （at 10 and 20 days after planting） was significant im-proved, which was in favor of procambium activity and tuberous roots formation. On the other hand, at early expansion period of tuberous roots, plastic film mulching cultivation increased abscisic acid （ABA） content and decreased gibberellin （GA） content in differentiated roots, as well as improved the secondary cambium activity, starch accumulation and differentiated root expansion. Meanwhile, abscisic acid （ABA） content and gibberellin （GA） content under the black film mulching significantly changed. Film mulching cultivation increased the number and fresh weight of tuberous roots per plant at 50 days after planting, which contrib-uted to higher fresh yield of tuberous root at harvest time. In the two year experiment, two treatments significantly enhanced the valid tuber number and fresh tuber yield compared with CK. The average increments were 10.71% and 5.76% in 2011, and 12.99%and 7.45%in 2012, respectively.