在高度饥馑条件下,大蒜幼苗发育过程中细胞内含物由衰老器官向新生部位的转移

在缺乏光照的条件下,把大蒜的蒜瓣培养在蒸馏水中,研究了新长出的叶片、根与蒜瓣之间在生长过程中细胞内含物再分配与再利用的进程及其与物质转移方式的可能关系。本工作表明,新长出的根、叶所需的营养物质最初全部来自蒜瓣的细胞内含物;并且是以新老器官更替的方式,由蒜瓣顺序转移到新生叶片中,并由先形成的叶片依次转移到尖端新生叶片及根中,使蒜瓣的细胞内含物反复多次地被再分配、再利用;同时,测定结果显示出第四片新叶中所含全 N 的三分之一是来自撤退的根系细胞内含物,最后由于根系的衰退而导致幼苗的过早死亡。此外、衰老器官向新生器官输出细胞内含物时,N.P.K 的输出与干物质的输出存在着明显的相关关系(r=0.98—0.99),表明细胞内含物的再分配是按着原有比例由衰老叶片陆续撤离的。这很难用通常的见解——细胞内含物的撤离必须先降解成溶质后再行转移——来解释,却有助于支持原生质主动撤离的假说。

WITHDRAWAL OF CELL CONTENTS FROM MATURE LEAVES FOR SUSTENANCE OF NEW APICAL GROWTHS DURING THE DEVELOPMENT OF A GARLIC SEEDLING UNDER STRICT STARVATION

Green Plants are autotrophic in nature.Not only does it manufa- cture its own food,(furnishing the materials to be consumed in respiration,secretion,etc.)but also conserve a large portion of its protoplasmic constituents.Most investigations on long-distance trans- port in plants deal with photosynthetic products from leaves and absorbed minerals from roots;yet,at different stages of development, snch as in seed germination where emergence of the vegetative body has just begun,and in early embryonic developm...