A pot experiment was conducted to study the influences of foliar application of glycine,alanine,lysine,and glutamic acid in 200 mg/kg or 500 mg/kg upon the quality and enzyme activity of flowering Chinese cabbage（Bra...A pot experiment was conducted to study the influences of foliar application of glycine,alanine,lysine,and glutamic acid in 200 mg/kg or 500 mg/kg upon the quality and enzyme activity of flowering Chinese cabbage（Brassica parachinensis Bailey）.The results showed that all the application of these four amino acids could increase the yield of flowering Chinese cabbage,significantly raise the content of soluble sugar,and reduce the accumulation of nitrate.The applications of three other amino acids except alanine can increase the content of soluble proteins and decrease the accumulation of oxalic acid.However,the application of amino acid has insignificant influences on the SPAD number of chlorophyll,and causes the decrease of Vitamin C content.Meanwhile,the application of amino acid can improve the activity of nitrate reductase（NR） and glutamate dehydrogenase（GDH） as well.It shows that the application of amino acid is beneficial to improve ammonia metabolism,reduce the accumulation of nitrate and oxalic acid,increase the content of soluble sugar and soluble proteins,and improve the quality of flowering Chinese cabbage.展开更多
Sap mixtures of the xylem, phloem, and vacuoles from low and high Cd accumulator varieties of Brassica parachinensis L. H. Bailey were analyzed under Cd stress to understand the biochemical mechanisms of Cd accumulati...Sap mixtures of the xylem, phloem, and vacuoles from low and high Cd accumulator varieties of Brassica parachinensis L. H. Bailey were analyzed under Cd stress to understand the biochemical mechanisms of Cd accumulation in plants. Low Cd accumulator ('Teqing-60') and high Cd accumulator ('Chixin-2') plants were grown in Cd-treated soil in pots in a greenhouse. Percentage of cell wall-bound Cd was estimated. pH level and the concentrations of amino acids, organic acids, anions, and cations in both stem and root saps were determined for the calculation of Cd speciations using the computer program GEOCHEM. The results showed that 'Teqing-60' had a significantly higher (P≤0.05) percentage of Cd bound to cell walls in roots and a significantly higher (P≤0.05) pH in the root sap. 'Teqing-60' also contained a higher concentration of total amino acids in both roots and stems compared with the high Cd accumulator variety 'Chixin-2'. However, between the two accumulators, for stems and for roots, there were no significant differences in non-amino organic acids. GEOCHEM calculations showed that Cd in the root sap of 'Teqing-60' mainly combined with amino acids, especially alanine. Compared with 'Chixin-2', in the root sap of 'Teqing-60', much lower levels of Cd as free ions or bound to simple ligands were found, indicating that less 'Teqing-60' is transferred to stems and leaves. Cadmium activity in the shoot sap of 'Teqing-60' was much lower than that in 'Chixin-2'; therefore, 'Teqing-60' exhibited higher Cd resistance. However, direct determination of the Cd complexes from xylem and phloem sap is needed to verify these results.展开更多
In Brassicaceae, myrosinase catalyzes the hydrolysis of glucosinolate and plays an important role in anti-herbivore defense. We have cloned and characterized the full- length complementary DNA of myrosinase gene from ...In Brassicaceae, myrosinase catalyzes the hydrolysis of glucosinolate and plays an important role in anti-herbivore defense. We have cloned and characterized the full- length complementary DNA of myrosinase gene from Brassicaparachinensis that exhibits high sequence identity with myrosinase genes from other Brassica species. To investigate the role of this myrosinase in defense against the diamondback moth （Plutella xylostella）, we constructed an RNA-interference （RNAi） cassette expressing a double-stranded RNA that targeted myrosinase and transfected it into B. parachinensis. Myrosinase was sup- pressed in the resulting transgenic plants. Diamondback moth larvae feeding on transgenic plants had lower larval and pupal weights, longer pupal duration, and lower fecundity than those feeding on non-transgenic plants, suggesting that the diamondback moth has adapted to the glucosinolate-myrosinase defensive system. Therefore, the suppression of myrosinase is a potential approach for controlling the diamondback moth.展开更多
基金Supported by National Scientific and Technological Supporting Project(2008BADA4B04-09)Guangdong Province Scientific and Technological Project(2008A020100017)Guangdong Province Department of Finance Project[(2006)143]~~
文摘A pot experiment was conducted to study the influences of foliar application of glycine,alanine,lysine,and glutamic acid in 200 mg/kg or 500 mg/kg upon the quality and enzyme activity of flowering Chinese cabbage（Brassica parachinensis Bailey）.The results showed that all the application of these four amino acids could increase the yield of flowering Chinese cabbage,significantly raise the content of soluble sugar,and reduce the accumulation of nitrate.The applications of three other amino acids except alanine can increase the content of soluble proteins and decrease the accumulation of oxalic acid.However,the application of amino acid has insignificant influences on the SPAD number of chlorophyll,and causes the decrease of Vitamin C content.Meanwhile,the application of amino acid can improve the activity of nitrate reductase（NR） and glutamate dehydrogenase（GDH） as well.It shows that the application of amino acid is beneficial to improve ammonia metabolism,reduce the accumulation of nitrate and oxalic acid,increase the content of soluble sugar and soluble proteins,and improve the quality of flowering Chinese cabbage.
基金Project supported by the National Natural Science Foundation of China (No. 40571141)the Natural Science Foundation of Guangdong Province (No. 021007)the Key Teachers Foundation of the Ministry of Education of China (No. 2000-143-39)
文摘Sap mixtures of the xylem, phloem, and vacuoles from low and high Cd accumulator varieties of Brassica parachinensis L. H. Bailey were analyzed under Cd stress to understand the biochemical mechanisms of Cd accumulation in plants. Low Cd accumulator ('Teqing-60') and high Cd accumulator ('Chixin-2') plants were grown in Cd-treated soil in pots in a greenhouse. Percentage of cell wall-bound Cd was estimated. pH level and the concentrations of amino acids, organic acids, anions, and cations in both stem and root saps were determined for the calculation of Cd speciations using the computer program GEOCHEM. The results showed that 'Teqing-60' had a significantly higher (P≤0.05) percentage of Cd bound to cell walls in roots and a significantly higher (P≤0.05) pH in the root sap. 'Teqing-60' also contained a higher concentration of total amino acids in both roots and stems compared with the high Cd accumulator variety 'Chixin-2'. However, between the two accumulators, for stems and for roots, there were no significant differences in non-amino organic acids. GEOCHEM calculations showed that Cd in the root sap of 'Teqing-60' mainly combined with amino acids, especially alanine. Compared with 'Chixin-2', in the root sap of 'Teqing-60', much lower levels of Cd as free ions or bound to simple ligands were found, indicating that less 'Teqing-60' is transferred to stems and leaves. Cadmium activity in the shoot sap of 'Teqing-60' was much lower than that in 'Chixin-2'; therefore, 'Teqing-60' exhibited higher Cd resistance. However, direct determination of the Cd complexes from xylem and phloem sap is needed to verify these results.
文摘In Brassicaceae, myrosinase catalyzes the hydrolysis of glucosinolate and plays an important role in anti-herbivore defense. We have cloned and characterized the full- length complementary DNA of myrosinase gene from Brassicaparachinensis that exhibits high sequence identity with myrosinase genes from other Brassica species. To investigate the role of this myrosinase in defense against the diamondback moth （Plutella xylostella）, we constructed an RNA-interference （RNAi） cassette expressing a double-stranded RNA that targeted myrosinase and transfected it into B. parachinensis. Myrosinase was sup- pressed in the resulting transgenic plants. Diamondback moth larvae feeding on transgenic plants had lower larval and pupal weights, longer pupal duration, and lower fecundity than those feeding on non-transgenic plants, suggesting that the diamondback moth has adapted to the glucosinolate-myrosinase defensive system. Therefore, the suppression of myrosinase is a potential approach for controlling the diamondback moth.
