残留地膜对棉花和玉米苗期根系形态和生理特性的影响

Effects of Agricultural Plastic Residual Films on Morphologic and Physiological Characteristics of Root System of Cotton and Maize in Seedling Stage

通过盆栽试验,研究不同残膜量(0、90、180、360、540、720、900 kg·hm^(-2))对苗期棉花和玉米生长(干物质、株高和叶面积)、根系形态(根长、根表面积)和根系生理(根系活力、过氧化氢酶CAT、过氧化物酶POD)的影响,并探究对两种作物根系影响差异显著的残膜量临界值。结果表明,在0~540 kg·hm^(-2)残膜量范围内,残膜对苗期棉花的株高和叶面积不会造成显著降低的影响;随着残膜量的增加,苗期玉米株高和叶面积逐渐降低,在90 kg·hm^(-2)残膜梯度下开始显著降低。随着残膜量的增加,苗期棉花和玉米的根长、根表面积以及根系活力、CAT和POD活性呈现先增加后降低的趋势,最大值出现在90~180 kg·hm^(-2)残膜量梯度范围内,最小值出现在900 kg·hm^(-2)残膜量。由于玉米的须根系众多,根系与残膜接触的面积大,导致苗期玉米产生显著差异的残膜量临界值小于苗期棉花。残膜量在90~180 kg·hm^(-2)区间内,残膜会作为一种适度胁迫,作物苗期根系会主动进行适应性的生长,超过该范围残膜会对作物根系的生长造成阻碍作用。

Pot experiments were conducted to study the effects of residual films（0, 90, 180, 360, 540, 720, 900 kg· hm^-2） on growth（dry mat- ter, height and leaf area）, root morphology （root length and root surface area） and root physiology （root activity, CAT and POD ） for cotton and maize in seedling stage, and the work was also to find the critical value of residual films which made obvious difference for two different crops in growth in seedling stage. The results showed that within the range from 0 to 540 kg＂ hm-2, residual films had no significant effect on the cotton height and leaf area in seedling stage, while maize height and leaf area decreased sustainably with the increase of residual films, which began to decrease markedly from the residual level of 90 kg .hm-2. Root growth and physiological indexes for cotton and maize in- creased firstly and then decreased with the increasement of residual films. The largest values of the root length and root surface area or the root activity, CAT and POD occurred in residual level of 90 to 180 kg· hm^-2. Maize had the less critical values of residual films than cotton in seedhng stage because maize had developed root system and exposed to more residues. It was concluded that appropriate residual films（90 to 180 kg·hm^-2） may promote the growth of seedling root, and residual films which is over that range will have a negative effect on the growth of seedling root.