Morphological Diversity in Cereal Plants as Adaptive Strategy, Its ecological Significance and Genetlc Control

1.对不同生态和遗传背景的水稻品种进行了根系形态观察。根系形态多样性是由根数和平均根长以及平均生长方向和平均根长共同决定的总根长及其分布格局的综合结果。根系形态多样性的发展可以根据连续植物体的数量和大小的增加来理解。由于节根原基可能引起植物根系形态的变异，因此对节根原基的位置和数目进行了遗传检测。旱稻和水稻根分生组织对土壤水分胁迫的响应方式不同。2.微管动态观察表明，在玉米伸长茎段，先分化出的肋状分生组织会转变为中间分生组织，而在非伸长部分，肋状分生组织不分化。茎的伸长方式和最终形状受肋分生组织的分化和活动持续时间的影响。此外，还对突变体的茎生长进行了遗传分析。3.小麦下胚根在生长早期主要由种子根组成，侧根发达。但在生长后期，它由节根组成。不同形态的根系在不同的土壤水分胁迫条件下，复水后表现为完全恢复吸水，相当于单位总叶面积的总根长，不包括在非常严重的胁迫后。

1.Root system morphology was examined in rice cultivars which are different from one another in ecological and genetic background. Diversity in root system morphoogy was caused by the combination of total root length and its distribution pattern which were determined by number and average length of nodal roots as well as average growth direction and average length of nodal roots, respectively. Development of diversity in root system morphology can be understood based on increase of number and size of successive phytomers. Position and number of nodal root primordia in phytomer were examined genetically, because they may cause the variations of root system morphology. Root system components of upland and lowland rice cutivars respond to soil water stress in different manners.2.Dinamics of microtubules shows rib meristem differentiated first will change into intercalary meristem in elongating stem part of maize whereas rib meristem is not differentiated in non-elongating part. Elongating pattern and final shape of stem are influenced by differentiation of rib meristem as well as its active duration. Mutant in stem growth was genetically analized in addition.3.Shwallow roots of wheat mainly consit of seminal roots with well-developed lateral root in the early growth stages. However, it is composed of nodal roots in the later growth stages. Root system with different morphology from experiences of different soil water stresses showed full recovery of water uptake after rehydration coresponding to total root length per total leaf area excluding after very severe stress.