‘鸭梨’ב京白梨’杂交后代果实有机酸积累差异及相关酶活性的研究

Difference of Acidity Accumulation and Related Enzyme Activities of Pear from Hybrid Offspring of‘Yali'בJingbaili'

该研究以‘鸭梨’ב京白梨’杂交后代高酸个体(GS-Y14)和低酸个体(DS-Y182)为试材,系统分析了果实发育过程中有机酸积累动态及相关酶活性的变化特征。结果表明:(1)GS-Y14属于苹果酸优势型果实,DS-Y182属于柠檬酸优势型果实,且成熟时两者在总酸含量上表现出的差异主要是由于苹果酸含量的差异所致。(2)苹果酸酶(NADP-ME)是苹果酸形成的关键酶,在梨果实发育过程中NADP-ME起分解作用,且该酶活性在两类个体果实发育后期差异显著,即NADP-ME是引起GS-Y14和DS-Y182中苹果酸含量不同的主要原因,进而导致成熟时两类个体果实酸积累的差异。(3)梨果实磷酸烯醇式丙酮酸羧化酶(PEPC)活性的升高有利于其柠檬酸的合成,而柠檬酸合酶(CS)是影响其柠檬酸含量变化的关键酶;细胞质乌头酸酶(Cyt-ACO)和线粒体乌头酸酶(Mit-ACO)早期对果实柠檬酸的含量变化影响较小,后期异柠檬酸脱氢酶(NAD-IDH)活性对柠檬酸在后代个体中的积累有一定影响。

In this study, two individuals, GS-Y14 with high acid content and DS-Y182 with low acid content, from hybrid offspring of ＇Yali＇ X ＇Jingbaili＇ were used to analyze the dynamic changes of organic acid and enzyme activities in pear fruit. The results showed that GS-Y14 belongs to malic acid dominant type,DS- Y182 belongs to the citric acid dominant type. The difference in total acid contents between DS-Y182 and GS-Y14 individual was mainly attributed to the content of malic acid during ripening. NADP-ME as key en- zyme plays a decomposition role in malic acid pathway, and showed significant difference near ripening in two species,so the NADP-ME was the main reason leading to the difference of malic acid between GS-Y14 and DS-Y182, and effect the final acid accumulation in fruit during ripening. The increasing activity of PEPC favored the synthesis of citric acid. CS is the key enzyme in the change of malic acid content. In the early period,Cyt-ACO and Mit-ACO showed little effects on the change of citric acid content. In the later period,the activity of NAD-IDH enzyme has a certain effect on the citric acid accumulation in different progeny.