摘要
在绿豆子叶衰老达到不归点(萌发后5～6d)前切除上胚轴可使开始衰老的子叶中核酸和蛋白质含量回升,衰老短期逆转。衰老不归点后的子叶中核酸和蛋白质变化的主要特征是:丧失了较多的核主带DNA、25S、18S rRNA以及大部分可溶性蛋白质组分,一种小分子DNA 组分完全消失。不归点前切除上胚轴可使上述核酸和蛋白质组分明显增加,表明子叶衰老的逆转可能与这些重要功能物质的回升有关。在切除上胚轴的茎顶涂抹IAA,能阻止子叶核酸和蛋白质回升,也消除了切除上胚轴对子叶裹老的逆转作用。
The decline of the contents of nu-cleic acids and protein in senescingcotyledons of mung bean (Plaseolus ra-diatus) was reverted to an increase, andhence the process of senescence was re-versed, when the epicotyl was removedbefore the point of no-return (betweenday 5 and day 6). Epicotyl removalafter the point of no-return had no ef-fect in reversing the senescence ofcotyledons and in recovering the loss ofnucleic acids and proteins. By compar-ing the cotyledons before and after thepoint of no-return, and the senes-cence-reversed cotyledons, differencesin the patterns of changes of differentcomponents of DNA, RNA and solubleproteins were observed. The cotyledonsafter the point of no-return had lost allof its low molecular weight DNA com-ponents, larger amount of nuclearmain-band DNA, 25 S. and 18 SrRNA and most of its soluble proteins.The cotyledons of a seedling fromwhich the epicotyl was removed beforethe point of no-return, showed signifi-cant increase in the amount of all theDNA and RNA component and almostall of the soluble proteins. Epicotyl re-moval prevented the low molecularweight DNA compeonent from degra-dation and stimulated the synthesis ofnew proteins. The results indicate thatthe irreversibility of cotyledon senes-cence may be related to the loss of theabove mentioned DNAs, RNAs andproeins, and that the reversion of thecotyledon senescence by epicotyl re-moval may be related to the recoveryof those components. Application onthe cotyledons of 6-BA could retard theprogress of cotyledon senescence, butdid not have the same effect as epicotylremoval. While the application of IAAon the top of a seedling ftom which theepicotyl had been removed could inhib-it the recovering effect of epicotyl re-moval on the contents of nucleic acidsand protein. This indicates that thesenescence of mung bean cotyledons isrelated to hormone, especially auxin,distribution.
基金
国家自然科学基金
关键词
绿豆
子叶
核酸
蛋白
衰老
上胚轴
mung bean cotyledon
epicotyl removal
reversion of senescence
nucleic acids
protein
