不同形态氮素对东北山樱幼苗根系呼吸代谢及生物量的影响

Effects of Different Nitrogen Forms on Root Respiratory Metabolism and on Biomass in Seedlings of Cerasus sachalinensis

以东北山樱(Cerasus sachalinensis Kom.)幼苗为试材,研究了不同形态氮素对根系呼吸代谢及植株生物量的影响。结果表明,在施氮量相同的条件下,施加硝态氮和酰胺态氮在整个试验过程中(28d)均显著提高了幼苗根系活力及呼吸底物的积累,而施加铵态氮对根系活力的促进作用只延续到处理后14d,随后根系活力和呼吸底物含量逐渐降低;硝态氮处理促进了三羧酸循环(TCA)关键酶的活性,TCA循环在呼吸代谢途径中的比例较对照提高了30.4%,呼吸代谢中间产物丙酮酸和柠檬酸增加,而磷酸戊糖途径(PPP)和交替途径(AP)较对照分别下降了35.0%和32.7%。铵态氮处理效应基本与之相反。酰胺态氮处理除对EMP关键酶活性及电子传递途径无明显影响外,与硝态氮处理效应相似;3种形态氮素处理对幼苗生长均有促进作用,对植株生物量促进作用的大小表现为硝态氮>酰胺态氮>铵态氮>对照。

The effects of different nitrogen forms on root respiratory metabolism and on biomass in seedlings of Cerasus sachalinensis Kom.were investigated.The results showed that,with a same amount of nitrogen application,the application of nitrate nitrogen and amidonitrogen significantly enhanced root activity and accumulation of respiratory substrates during the whole experimental period（28 d）,while the application of ammonium nitrogen only enhanced the root activity and the accumulation of respiratory substrates during the 14 days after the application.Whereafter,the root activity and respiratory substrate content significantly decreased.Application of nitrate nitrogen enhanced the activities of key enzymes in tricarboxylic acid（TCA）cycle,increased the ratio of TCA cycle to the total respiratory pathway by 30.4% compared to that in the control and increased the content of pyruvic acid and citric acid the intermediates of respiratory metabolism.Whereas,the pentose phosphate pathway（PPP）and the alternative oxidase（AOX）pathway were decreased by 35.0% and 32.7% respectively at the same time.The application of ammonium nitrogen had opposite effect to the application of nitrate nitrogen on activities of key enzymes in TCA cycle,on TCA cycle,intermediates of respiratory metabolism,PPP and AOX pathways.Application of amidonitrogen had similar effects to the application of nitrate nitrogen except having no obvious effect on activates of key enzyme in glycolysis pathway（EMP）and in respiratory electron transport.The application of the three different types of nitrogen improved the growth of the seedlings.The enhancement of biomass by the application of the 3 types of nitrogen was nitrate nitrogenamidonitrogenammonium nitrogencontrol.