小麦穗、小穗及籽粒差异的解剖结构及生理原因的研究

小麦主茎、一蘖和二蘖的穗下节间及其下第二节间的直径、基本组织面积、维管束数目、维管束面积及韧皮部面积等均有差异；穗中不同部位小穗的小穗轴中的维管束分布也有差异；不同一小穗中，通向各小花的维管束数目和面积也有不同。在穗的发育过程中，植株及穗部器官中的可溶性糖及氨基酸的含量在不断变化而且其分配也不平衡。

Studies on the Anatomical and Physiological Factors Influencing the Unbalanced Development of the Spikes, Spikelets and Grains of Wheat

Some anatomical and physiological characteristics of some organs of wheat werestudied to investigate their relationship with the unbalanced development of the spikes,spikelets and grains at different positions. The results indicated that: (1) Thediameter and area of the cross sections of the 2 upper internodes, the number andsize of vascular bundles and area of the phleom of main stem are larger than thoseof the 1st and 2nd tillers. These facts suggest that such structural differences might bethe cause of the unbalanced development of different spikes. (2) Anatomical studies ofthe vascular systems of the spikelets showed that the vascular bundles of the 1st and2nd florets were linked to 2 independent vascular strands originated from the rachis,but those of the 3rd floret were branched from the base of the 2nd floret. This mightbe the cause of the unequal sizes of grains at different positions on a spikelet. (3)The soluble sugar and amino acid contents in the tillers, spikelets and grains at differ-ent positions were unbalanced, closely related to the unbalanced development of theseorgans. The C/N ratio of the beter development parts suggested that a more balancedC/N ratio is necessary for the optimum differentiation and development of wheatorgans. The application of these knowledge on the culture practices of wheat was alsodiscussed.