不同采收期红香椿硝酸还原酶活性及亚硝酸盐含量的变化

Changes of Nitrate Reductase Activity and Nitrite Content of Toona sinensis Buds in Different Harvesting Times

以红香椿嫩芽为试验材料,研究了同茬6个不同采收期叶和茎中硝酸还原酶（Nitrate reductase,NR）活性及亚硝酸盐含量的变化,旨在为其适时采收提供理论依据。结果表明,不同采收期红香椿嫩芽叶的NR活性和亚硝酸盐含量明显高于茎;随着采收期的延长,叶和茎中NR活性和亚硝酸盐含量明显升高,4月29日采收的（Ⅵ期）香椿嫩芽中NR活性和亚硝酸盐含量最高。综合外观品质、食用性及亚硝酸盐含量,4月21~23日（Ⅱ期和Ⅲ期）为最适宜采收期。

With the aim of providing a theoretical basis for the best harvesting time of Toona sinensis buds, the nitrate reductase activity and nitrite content in its leaves and stems were investigated in five different harvesting times. The results showed that the nitrite content and nitrate reductase activity in leaves were significantly higher than those in stems. With the delay of harvesting time, the nitrite content and nitrate reductase activity in leaves and stems obviously increased, and those in buds harvested at April 29 （phase VI ） were the highest. Considering exterior quality, edibility and nitrite content, April 21 -23 （phase Ⅱ and Ⅲ ） were the best harvesting time for Toona sinensis buds.