DNP和ATP对Phomopsis longanae Chi侵染的龙眼果实病害发生、能荷状态和呼吸代谢的调控

Regulation of 2,4-dinitrophenol and Adenosine Triphosphate on Disease Development, Energy Status, and Respiratory Metabolism of Phomopsis longanae Chi-infected Longan Fruit

与拟茎点霉接种果实相比,DNP能提高拟茎点霉接种果实的病害指数和果皮褐变指数,提高果实呼吸速率和果皮COX、AAO、PPO活性及NAD和NADH含量,降低果皮NADK活性和NADP、NADPH含量及能荷值。而ATP则能降低拟茎点霉接种果实的病害指数和果皮褐变指数,降低果实呼吸速率和果皮COX、AAO、PPO活性及NAD和NADH含量,提高果皮NADK活性和NADP、NADPH含量,维持较高的果皮能荷值。据此认为,DNP处理促进拟茎点霉侵染所致龙眼果实采后病害发生,与DNP加剧能量亏缺、削弱磷酸戊糖呼吸代谢途径及增强COX、AAO和PPO等呼吸末端氧化酶活性有关;而ATP处理延缓拟茎点霉侵染所致龙眼果实采后病害发生,与ATP维持较高的能荷值、增强磷酸戊糖呼吸代谢途径及降低COX、AAO、PPO等呼吸末端氧化酶活性有关。

The DNP treatment increased the contents of nicotinamide adenine dinucleotide(NAD) and reduced NAD(NADH), decreased NAD kinase(NADK) activity in the pericarp, and led to lower contents of NAD phosphate(NADP) and reduced NADP(NADPH) and a lower level of energy charge. By contrast, ATP treatment reduced the disease index and pericarp-browning index for P. longanae-inoculated longans, and decreased the respiration rate of the fruit as well as the activities of COX, AAO, and PPO in the pericarp. Additionally, ATP treatment reduced the contents of NAD and NADH, increased NADK activity in the pericarp, and led to higher contents of NADP and NADPH and a higher level of energy charge. These results suggest that DNP treatment accelerates the development of postharvest disease in P. longanaeinfected longans through exacerbating energy deficiency, decreasing pentose phosphate pathway activity in respiration and metabolism, and increasing the activities of respiratory terminal oxidases such as COX, AAO, and PPO. On the other hand, ATP treatment likely delayed the development of postharvest disease in P. longanae-infected longans through maintaining a relatively high level of energy charge, increasing PPP activity in respiration and metabolism, and decreasing the activities of respiratory terminal oxidases such as COX, AAO, and PPO.