Studies on the Physiological Effects of AlCl3 on Roots of Rice Seedlings
Date Issued
2006
Date
2006
Author(s)
Wang, Jen-Wu
DOI
zh-TW
Abstract
Chapter 2
The effect of AlCl3 on endosperm reserve mobilization of rice grains or dehulled rice grains during germination was investigated. AlCl3 had no effect on grain dry weight (DW), grain fresh weight (FW), protein and starch contents in endosperm, α-amylase and protease activities in endosperm of germinating rice grains. However, when dehulled rice grains were treated with AlCl3, AlCl3 inhibited the decrease in DW, FW, and starch and protein contents, and the increase in α-amylase and protease activities in endosperm. Evidence is provided to show that the hull is a barrier against influx of Al to endosperm.
Chapter 3
AlCl3 dissolved in half-strength Kimura B nutrient solution was observed to be less effective in inhibiting root growth of rice seedlings than that dissolved in distilled water. Kimura B nutrient solution is composed of inorganic salts and citrate. Thus, we investigated the influence of inorganic salts and organic acids on AlCl3-inhibited root growth of rice seedlings. It was observed that CaCl2, MgCl2, NaH2PO4, citrate, malate, tartarate, and oxalate were able to reduce AlCl3-inhibited root growth of rice seedlings. The effect of CaCl2, MgCl2, and organic acids on AlCl3-inhibited root growth is mediated through reducing Al level in roots of rice seedlings.
Chapter 4
The effect of AlCl3 on the antioxidant system of rice roots and the role of antioxidants AsA and GSH in AlCl3-inhibited growth of rice roots were investigated. AlCl3 treatment resulted in a rapid inhibition of root growth but had no effect on lipid peroxidation and antioxidative enzyme activities in rice roots. AlCl3 treatment resulted in lower content of H2O2, AsA, and GSH than controls. Exogenous AsA or GSH conteracted growth inhibition by AlCl3. AlCl3 treatment increased syringaldazine peroxidase (SPOX) activities and lignin content in rice roots. Exogenous AsA or GSH prevented the decrease in H2O2 content and the increase in SPOX activities and lignin content in rice roots caused by AlCl3. Results suggest that lignification induced by low AsA or GSH content may explain the mechanism of Al-inhibited growth of rice roots.
Chapter 5
The effects of AlCl3 on growth and polyamine levels of rice roots were investigated. When rice roots were treated with AlCl3, root growth was markedly inhibited. AlCl3 treatment resulted in a higher putrescine content and lower spermidine and spermine contents in rice roots. D-Arginine and a-methylornithine, inhibitors of putrescine biosynthesis, caused a reduced content of putrescine in rice roots under Al stress. AlCl3 treatment also resulted in a decrease in diamine oxidase activity in rice roots. The growth of rice roots in the presence of AlCl3 was recovered after the addition of D-arginine or a-methylornithine. The protective effect of D-arginine or a-methylornithine in counteracting AlCl3-inhibited growth of rice roots is unlikely caused by reduction of Al uptake. Furthermore, the effect of the growth recovery in AlCl3-treated rice roots by D-arginine or a-methylornithine was reversed by the addition of putrescine. Our results strongly suggest that putrescine accumulation is a factor causing growth inhibition of rice roots under Al tress. Evidence is also presented to show that lignification is responsible for putrescine- and AlCl3-inhibited growth of rice roots.
Subjects
水稻
氯化鋁
生長
水解酵素
有機酸
氧化逆境
抗敗血酸
多元胺
木質素
rice
AlCl3
growth
hydrolytic enzymes
organic acids
oxidative stress
ascorbic acid
polyamines
lignin
Type
thesis
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