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利用盆栽试验,研究了不同水分亏缺[土壤含水量分别为田间持水量的75%～85%(对照)、65%～75%(轻度)、55%～65%(中度)、45%～55%(重度)]对玉米苗期根系发育及解剖结构的影响.结果表明:干旱抑制了植株生长,随着水分亏缺程度的加重,根系长度缩短、根直径变细、总生物量降低;而根系活力、根冠比、根尖多糖含量均增加;侧根根毛长度、根毛密度、根毛总长度在中度水分亏缺条件下达到最大.组织切片观察结果表明,根直径变细主要是由于根的中柱面积减小、导管直径缩小所致,不同水分亏缺处理间导管的数量差异不大,但水分亏缺使导管壁变得不规整.根尖多糖含量的增加主要表现在表皮细胞和根冠细胞内,在表皮细胞内多糖主要以游离形式分布,在根冠细胞内主要以淀粉粒形式分布.总之,在水分亏缺条件下,玉米通过改变导管结构、增加表皮细胞与根冠细胞内多糖的含量及扩大根毛总表面积,来调节根系对水分的吸收能力,增强玉米植株的抗旱性,但根毛并不随着亏缺程度的加重而无限制的增长,在过度干旱条件下,根毛会受到抑制或损伤.
Pot experiments were conducted to study the effects of different water deficits (soil moisture content of 75% ~ 85% (control), 65% ~ 75% (mild), 55% ~ 65% % ~ 55% (severe)] on the root development and anatomy of maize seedling.The results showed that: the drought inhibited the plant growth, with the increase of water deficit, the root length shortened, the diameter of the root became thinner, the total biomass But root activity, root / shoot ratio and root polysaccharide content increased.The root hair length, root hair density and root hair length of lateral root reached the maximum under the condition of moderate water deficit.The observation results of tissue section showed that the root diameter was thinner Due to the decrease of the central column area and the decrease of the diameter of the catheter, the number of catheters in different water deficit treatments did not differ significantly, but the water deficit caused the irregularity of the catheter wall.The content of polysaccharides in the apical surface increased mainly in the epidermis In the cells and root cap cells, the polysaccharides in epidermal cells mainly distributed in free form and distributed mainly in the form of starch grains in root and shoot cells.In short, under the condition of water deficit, corn changed the structure of the duct and increased the number of epidermal cells and roots Cellular polysaccharide And expand the total surface area of root hair to regulate the water absorption capacity of the root system to enhance the drought resistance of maize plants, but root hairs do not increase with the degree of indefinite increase without restriction, under extreme drought conditions, root hairs will be inhibited or damage.