| Summary: | 碩士 === 國立中興大學 === 植物學系 === 84 === The research is using 75mM NaCl and 150mM NaCl to deal with
the rice inhydroponic culture system, and discussing the
physiological change andultrastructure of the rice leaves and
its roots under salt stress. The resultis found that the growth
of the rice is inhibited under salt stress, and thestomatal
conductance and photosynthetic rate will also decrease when
theincreasing concentration of salt stress . Salt stress will
also cause thedecreasing of the respiration rate, and the
activity of alternative pathway ofroots will increase because
of salt stress, but the increasing leavel willdepend on whether
the rice is salt-tolerate or not. On the 16th day of IR34under
salt stress, the alternative pathway has already start to
decrease; onthe opposite, the activity of alternative pathway of
TNS19 under salt stressis still higher than the control one.
When the rice is under salt stress, thesoluble sugar content in
its leaves and roots will increase with the
increasingconcentration of salt stress. The increase of soluble
sugar content can increasecompatible solutes and respiration
materials. And the soluble sugar in leavescan be found mostly
sucrose, and in roots mostly glucose. The salt-toleraterice
(TNS19), the activity of SPS of leaves and roots will increase
with theincreasing concentration of salt stress; the salt-
sensitive rice (IR34), the activity of leaves also increase, but
one of roots tends to decrease. In addition,as for the enzyme (
SS, NI, and AI ) which hydrolyzed sucrose, the activity hasthe
decreasing tendency under salt stress. And starch content will
also decreasess. Thus, under salt stress, the plant will
increase the soluble sugar contentto be used as compatible
solutes and respiration materials. As for free aminoacid, salt
stress will cause a greataccumulation of proline, which can be
usedas compatible solutes, and the roots have a great increasing
on the content ofglutamine, glutamate, asparigine, and asparate.
The situation of which maybehave a close relation with the
reutilization and transport of nitrogen.Moreover, according to
SDS-PAGE, it can be found that salt stress will inducethe new
synthetic protein.Under salt stress, the main change of
ultrastructureis that the thylakoid of chloloplast is gradual
breakdown from the parallelstack, and the starch in chloroplast
also have be hydrolyzed; the root cellsmostly become some big
vacuole, or even some cell wall. The change level ofthe
ultrastructure also will be different along with whether the
rice issalt-tolerate or not.
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