遮荫对玉米茎秆形态特征、穿刺强度及抗倒伏能力的影响

Effects of Shading on Stalk Morphological Characteristics,Rind Penetration Strength and Lodging-resistance of Maize

大田条件下,研究遮荫处理对玉米不同类型品种的茎秆形态特征及抗倒力学强度的影响。结果表明:稀植大穗品种JK519对弱光胁迫反应较为敏感,遮荫处理后玉米株高和穗位高均显著下降,叶面积指数降低。基部节间缩短、直径变小,单位节间长干质量减少。茎秆穿刺强度在30%和60%遮荫条件下分别下降36.4%和66.0%,田间倒伏率严重。而紧凑耐密品种CS1在遮荫30%胁迫下穗位高、LAI下降不明显;节间缩短,但直径和单位节间长干质量变化不大;穿刺强度仅下降5.9%,田间倒伏较轻;在遮荫60%胁迫下,穿刺强度明显下降,倒伏加重。同时各个品种均随遮荫程度的增加,最终玉米产量、收获穗数、单穗粒数和千粒重明显降低。因此,30%遮荫处理(弱光胁迫)可推荐作为玉米高产抗倒品种茎秆力学强度鉴定和筛选条件之一。

Under field condition,effects of shading on stalk mechanical and rind penetration strength were investigated using three maize cultivars differing in lodging resistant ability,i.e.JK519,CS1 and ZD958.The results showed that JK519 with a large spike under thinned planting density was sensitive to shade stress,its plant height and ear height were decreased significantly,and LAI（leaf area index） was also declined.With lower internodes diameter and shorter internodes length at basal stem,the ratio of dry weight to length of internodes was reduced in shading condition.The rind penetration strength of JK519 was decreased by 36.4% and 66.0% under a shading intensity of 30% and 60%,respectively;and field lodging seriously.However,with a shading intensity of 30%,CS1（a compact and tolerant to high density type） was declined slightly in the ear height,LAI and internodes diameter,and its rind penetration strength was only decreased by 5.9%.The rind penetration strength was decreased obviously by 60 % shading intensity,lodging heavily.Meanwhile,the finally maize yield,the number of harvest ear and grain per ear,and weight of 1 000 kernels of three maize cultivars were decreased significantly with increasing shading intensity.The 30% shading intensity should be definite as an appraise and selection condition of the mechanical strength of maize high yield and lodging resistance.