中文摘要：

为了研究通气组织在缺磷植物中的生理作用，对低磷胁迫下玉米种子根通气组织的形成时间进行了观察。并比较了磷营养效率不同的8个玉米自交系根组织结构的差异。结果表明，在低磷胁迫下，玉米种子根内皮层细胞解体及通气组织的形成早于植株生物量、根冠比、比根长的变化，甚至早于茎叶磷浓度的变化；在相同的磷胁迫下，不同基因型玉米根内通气组织的发育状况呈现出显著差异，而且通气组织的发育面积与玉米比根长呈显著正相关。同时。比根长的增加意味着根系与土壤接触面积的增加，且被普遍认为是植物适应低磷胁迫的机制之一，所以玉米根内通气组织的形成可能与玉米适应低磷胁迫有关。

英文摘要：

It is well known that aerenchyma formation in root cortical section is due to hypoxia, and this has been considered as an adaptation of landplant to flooding. It has been shown recently by our work that hypoxia is not the only factor which can induce aerenchyma formation in root cortex. Using wheat, maize and common bean as materials, we have found that root cortical cells lysed and formed lysigenetic aerenchymas too when plants grew in low phosphorus condition（ 1 μmol/L） with sufficient oxygen supply. This implys lysigenetic aerenchyma formation may have other physiological roles beyond providing channel for oxygen transportation from above-ground shoot to under-ground root tissue. The objectives of this study was to elucidate the role of aerenchyma in P stressed plants. The procedure of aerenchyma formation in low P stressed maize roots and the aerenchyma development of different maize inbred lines with different P efficiencies were observed and compared. The results showed that after 4 d of treatment, root cortical cells were lysed and aerenchyma formed in low P （ 1 μmol/L） maize root, while no any visible change observed in high P （1 mmol/L） root cortex（ Fig. 1 ）. Root/shoot ratio and specific root length in low P nutrient condition began to be significantly different from those in high P condition after 8 d of treatment （Fig. 2, Table 2）. Shoot P concentrations of maize plants in low P or high P conditions kept no significant difference until 6 d of treatments（Table 1 ）. This suggests that root histological change or aerenchyrna formation appears earlier than the changes of morphological indice such as root/shoot ratio and specific root length of maize seedings transplanted in low P nutrient solution, the cortical cells lyse or aerenchyma forms even before shoot P concentration begin to be changed significantly. The maize genotypes with contransting P efficiencies developed different volume of aerenchyma in roots when they were supplied with same low P nutrition（ Fig. 3）. Statis