甜菜块根三生构造的形成及发育过程初探

通过“新甜二号”块根三生构造的形成及发育过程观察看出:甜菜块根三生构造的形成始于一对真叶期,从二对真叶到块根糖分增长期前期是块根三生维管束环的主要形成时期。块根内对三生维管束环上的三生维管束束数随块根三生维管束环数的增加而增加,二者之间里显著的直线相关。而且块根内的三生维管束环数及环上的束数都具有极限性。块根最外2—3环上的三生维管束束数虽多,但成熟的较少。块根内各环间距随三生维管束环数的增加而呈动态变化,环间距增长最快在叶丛繁茂中期到块根糖分增长期中后期。生育后期,根内以第三环间距最大,而且根内各环间距的大小与环数之间呈Y=ae~(bx)·x的函数关系。

A PRELIMINARY STUDY ON THE FORMATION AND DEVELOPMENT OF FRTIARY STRUCTURE IN TEEEROOT TUBER OF SUGER BEET

In this study the formation and development of the tertiary structure in the root tuber of suger beet i.e.Xing Tian No.2 variety had been observed. The results showed that the formation of the tertiary structure in root tuber started at the period of a pair of euphylla,and the main forml-ng.time of the. ring which consists of the tertiary vascular Lundles was from the presence of two pairs of euphylla to the earlier stage in thesug-er increasing period in root tuber. It was indicated that the increase in numbers of the vascular bundle which exists on the ring of the tertiay vascular bundle followed that of the ring of the tertiary vascular bundle, and the. numbers of vascular bundle exhibited a significant linear correlation with that of ring. In addition, both the numbers of the stertiary vascular bundle ring and that of bundle on the ring were limited. Although the numbers of the stertiary vascular bundle on the outermost 2-3 rings in root tuber were great, only Some of them matured. It had also been demonstrated that the spacing between rings in root tuber dynamicauy varied with the increasing of rings of the stertiary vascular bundle besides, the spacing between rings extended most rapidly from the mid-stage in the lush period of the foliage to the mid-late sta-ge in the period of sugar increase in root tuber. It was especially pointed out that during the later developing time of sugar beet, the spacing between the second and third rings in root tuber extended to the fullest extent; furthermore, the varying of spacing between rings in root tnber was functionally relative with the numbers of the ring, and whose relationship could be expressed with a formula, i.e. "Y=a.eb.xn.