Wild-type(Zhonghua 11) and mutant rice(Oryza sativa L.) plants were used to investigate the effect of cadmium(Cd) application on biomass production,to characterize the inffux of Cd from roots to shoots,and to determin...Wild-type(Zhonghua 11) and mutant rice(Oryza sativa L.) plants were used to investigate the effect of cadmium(Cd) application on biomass production,to characterize the inffux of Cd from roots to shoots,and to determine the form,content,and subcellular distribution of Cd in the roots,leaf sheaths,and leaves of the rice plants.Seedlings were cultivated in a nutrient solution and were treated with 0.5 mmol L-1 of Cd2+ for 14 d.The sensitivity of rice plants to Cd toxicity was tested by studying the changes in biomass production and by observing the onset of toxicity symptoms in the plants.Both the wild-type and mutant rice plants developed symptoms of Cd stress.In addition,Cd application significantly(P ≤ 0.01) decreased dry matter production of roots,leaf sheaths,and leaves of both types,especially the mutant.The Cd content in roots of the mutant was significantly(P ≤ 0.05) higher than that of the wild-type rice.However,there was no significant di?erence in the Cd content of roots,leaf sheaths,and leaves between the wild-type and mutant rice.Most of the Cd was bound to the cell wall of the roots,leaf sheaths,and leaves,and the mutant had greater Cd content in cell organelles than the wild type.The uneven subcellular distribution could be responsible for the Cd sensitivity of the mutant rice.Furthermore,different chemical forms of Cd were found to occur in the roots,leaf sheaths,and leaves of both types of rice plants.Ethanol-,water-,and NaCl-extractable Cd had greater toxicity than the other forms of Cd and induced stunted growth and chlorosis in the plants.The high Cd content of the toxic forms of Cd in the cell organelles could seriously damage the cells and the metabolic processes in mutant rice plants.展开更多
To investigate the relationships among β-mannanase, β-mannosidase and a-galactosidase required for degrading galactomannan in cell wall during and following rice seed germination, the activities of the three enzymes...To investigate the relationships among β-mannanase, β-mannosidase and a-galactosidase required for degrading galactomannan in cell wall during and following rice seed germination, the activities of the three enzymes and the effects of ABA and GA3 on them were surveyed. The activities of β-mannosidase and a-galactosidase presented in dry and pre-germinated rice seeds, and increased slowly during and following germination. However, the activity of β-mannanase was detected only after germination. GA3 could promote the activities of β-mannanase and a-galactosidase. ABA had little effect on the activities of β-mannosidase and α-galactosidase, but it could seriously inhibit the activity of β-mannanase.展开更多
基金the National Natural Science Foundation of China (No30671255)the National Key Technologies R&D Program of China during the 11th Five-Year Plan Period (No2006BAK02A18)the National Basic Research Program (973) of China (No2002CB410804)
文摘Wild-type(Zhonghua 11) and mutant rice(Oryza sativa L.) plants were used to investigate the effect of cadmium(Cd) application on biomass production,to characterize the inffux of Cd from roots to shoots,and to determine the form,content,and subcellular distribution of Cd in the roots,leaf sheaths,and leaves of the rice plants.Seedlings were cultivated in a nutrient solution and were treated with 0.5 mmol L-1 of Cd2+ for 14 d.The sensitivity of rice plants to Cd toxicity was tested by studying the changes in biomass production and by observing the onset of toxicity symptoms in the plants.Both the wild-type and mutant rice plants developed symptoms of Cd stress.In addition,Cd application significantly(P ≤ 0.01) decreased dry matter production of roots,leaf sheaths,and leaves of both types,especially the mutant.The Cd content in roots of the mutant was significantly(P ≤ 0.05) higher than that of the wild-type rice.However,there was no significant di?erence in the Cd content of roots,leaf sheaths,and leaves between the wild-type and mutant rice.Most of the Cd was bound to the cell wall of the roots,leaf sheaths,and leaves,and the mutant had greater Cd content in cell organelles than the wild type.The uneven subcellular distribution could be responsible for the Cd sensitivity of the mutant rice.Furthermore,different chemical forms of Cd were found to occur in the roots,leaf sheaths,and leaves of both types of rice plants.Ethanol-,water-,and NaCl-extractable Cd had greater toxicity than the other forms of Cd and induced stunted growth and chlorosis in the plants.The high Cd content of the toxic forms of Cd in the cell organelles could seriously damage the cells and the metabolic processes in mutant rice plants.
基金supported by the Project of National Key Basic Research and Development, China (Grant No. 2002CB410804)the Natural Science Foundation of Guizhou Province, China (Grant No. 20072058)the Foundation for Young Scholars Scientists of Guizhou University (Grant No. X060036), China.
基金supported by the National Natural Science Foundation of China(Grant No.30370913)the Guangdong Provincial Natural Science Foundation(Grant No.32264).
文摘To investigate the relationships among β-mannanase, β-mannosidase and a-galactosidase required for degrading galactomannan in cell wall during and following rice seed germination, the activities of the three enzymes and the effects of ABA and GA3 on them were surveyed. The activities of β-mannosidase and a-galactosidase presented in dry and pre-germinated rice seeds, and increased slowly during and following germination. However, the activity of β-mannanase was detected only after germination. GA3 could promote the activities of β-mannanase and a-galactosidase. ABA had little effect on the activities of β-mannosidase and α-galactosidase, but it could seriously inhibit the activity of β-mannanase.
