节瓜生育过程RubisCO活性与氮钾营养的关系

CHANGE OF RUBPCASE/OASE ACTIVITY IN DIFFERENT GROWTH PERIODS AND ITS RELATIONSHIP WITH NITROGEN AND POTASSIUM NUTRITION IN CHIEH-QUA(BERNINCASA HISPIDA COGNVARCHIEH-QUA HOW)

研究了节瓜生育过程中叶片核酮糖－１，５－二磷酸羧化酶／加氧酶（ＲｕｂｉｓＣＯ）活性的变化及其与氮钾营养的关系氮钾营养设置低氮低钾（Ｎ１２Ｋ９）、低氮中钾（Ｎ１２Ｋ１８）、低氮高钾（Ｎ１２Ｋ３６）、高氮低钾（Ｎ１８Ｋ９）、高氮中钾（Ｎ１８Ｋ１８）和高氮高钾（Ｎ１８Ｋ３６）等６个处理结果表明：在节瓜的生育过程，叶片的ＲｕｂｉｓＣＯ羧化活性和羧化／加氧活性比不断提高，加氧活性则不断降低盛收期植株第１１－２０节的低节位叶片的ＲｕｂｉｓＣＯ羧化活性和加氧活性都最高，羧化／加氧活性比较高；第２１－３０节的中节位叶片的羧化活性较高，加氧活性最低，羧化／加氧活性比最高；第３１－３５节的高节位叶片的羧化活性最低，加氧活性较高，羧化／加氧活性比最低无论氮水平高低，中钾比低钾和高钾都提高ＲｕｂｉｓＣＯ羧化活性和羧化／加氧活性比在３种钾水平下，高氮比低氮降低ＲｕｂｉｓＣＯ羧化活性和羧化／加氧活性比。

Experiments were carried out on the change of RuBPCase/Oase activity in different growth periods and its relationship with nitrogen and potassium nutrition in Chieh-qua. Six treatments were set, including low or high level of nitrogen(12 or 18 kg N/1 000 m2) in combination with low, medium and high levels of potassium (9、18、36 kg K2O/1 000 m2) respectively. RuBPCase activity and activity ratio of RuBPCase/Oase increased gradually during growth and development period, but RuBPOase activity decreased. The highest activities of both RuBPCase and RuBPOase were found in the leaves on low nodes (11～20th nodes) in the full fruit period, while the lowest activities of RuBPCase and RuBPOase were respectively found in the leaves on high nodes (31～35th nodes) and middle nodes (21～30th nodes). The activity ratio of RuBPCase/Oase was the highest in the middle-node leaves and lowest in the high-node leaves. Under either low or high nitrogen level, RuBPCase activity and activity ratio of RuBPCase/Oase in medium potassium level were higher than those of low or high potassium level. Under three potassium levels, high nitrogen resulted in lower RuBPCase activity and activity ratio of RuBPCase/Oase, but higher RuBPOase activity than that of low nitrogen.