2,4-D处理对欧李果实钙摄取的影响及与有机酸代谢和IAA的关系

Effect of 2,4-D Treatment on Calcium Uptake and the Relationship with IAA and Organic Acid Metabolism in Cerasus humilis Fruit

为探究外源植物生长调节剂2,4-D处理对欧李(Cerasus humilis)果实发育成熟过程中钙素摄取能力的影响及与有机酸代谢、生长素(IAA)之间的关系,以内蒙古地区的低钙欧李MY-9果实为试材,以清水喷施作为对照,研究2,4-D处理对果实发育成熟过程中钙摄取能力和有机酸代谢及IAA的影响,并进行相关性分析。结果表明(:1)在摄钙速率方面,处理与对照果实的果胶钙、活性钙、总钙的摄钙速率变化规律相似,均表现为先升后降,处理后从硬核期到完熟期以上3种钙的摄取速率均显著高于对照;而水溶钙摄钙速率与其相反,表现为先降后升,果实发育后期显著高于对照。在摄钙活性方面,4种钙形态的变化规律相似,均表现为持续下降,处理后果实的摄钙活性均显著高于对照。在相对生长钙摄取量方面,4种钙形态的变化规律一致,均表现为先升后降,硬熟期和完熟期处理显著高于对照。(2)处理与对照果实中苹果酸脱氢酶(NAD-MDH)活性、苹果酸及有机酸含量随着果实发育成熟均呈上升趋势,苹果酸酶(NADP-ME)活性和柠檬酸含量均呈下降趋势,2,4-D处理可以不同程度提高果实中有机酸含量及相关酶活性。(3)处理与对照果实的IAA含量整体上均表现为先升后降,整个发育时期处理与对照均存在显著差异,2,4-D处理可显著提升欧李果实IAA含量。(4)相关性分析表明,水溶钙的摄钙速率和相对生长钙摄取量与NAD-MDH活性、苹果酸及有机酸含量均呈显著正相关,与IAA含量、NADP-ME活性及柠檬酸含量呈显著负相关;果胶钙、活性钙及总钙的摄钙活性与IAA含量、NADP-ME活性、柠檬酸含量呈显著正相关,与NAD-MDH活性、苹果酸及有机酸呈显著负相关;2,4-D处理提升了果实钙摄取能力与柠檬酸含量的相关性。综上所述,2,4-D处理可以提高欧李果实中钙摄取能力,提高有机酸代谢及IAA含量;欧李果实中钙摄取能力与有机酸代谢及IAA含量密切相关,随着NAD-MDH活性增强,苹果酸含量增加,有机酸含量增加,会提高水溶钙摄取能力,但会降低果胶钙、活性钙及总钙的摄取能力;而柠檬酸及IAA含量的增加会降低水溶钙摄取能力,提高果胶钙、活性钙及总钙摄取能力。2,4-D处理通过提高有机酸代谢及IAA含量调控果实钙摄取。

The objective of this study was to investigate the relationships between calcium uptake,organic acid metabolism and IAA during the development and ripening of Cerasus humilis fruit by treatment with exogenous plant growth regulator 2,4-D.The low-calcium C.humilis MY-9 fruit in Inner Mongolia was sprayed for 2,4-D at the young fruit stage and the coloring and swelling stage,and the effects on calcium uptake and organic acid metabolism and IAA during fruit development and maturity under 2,4-D treatment were studied with clean water treatment as control,and correlation analysis was carried out.The results showed that(1)In terms of calcium uptake rate,the uptake rate of pectin calcium,active calcium and total calcium was similar to that of the control,which increased first and then decreased,the uptake rate of the above three types of calcium from hard core stage to maturity stage was significantly higher than that of the control.On the contrary,the uptake rate of water-soluble calcium decreased first and then increased,and the value at late stage of fruit development was significantly higher than that of the control.In terms of calcium uptake activity,the changes of the four calcium forms were similar,showing a continuous decrease,and the calcium uptake activity of the treatment was significantly higher than that of the control.In terms of relative-growth calcium uptake,the changes of the four calcium forms were consistent,all of which increased first and then decreased,and the value of treatment at the hard-core and full-maturity stages was significantly higher than that of the control.(2)The activity of NAD-MDH,the amount of malic acid and organic acid increased with the development and maturity of fruits,and the activity of NADP-ME and citric acid decreased with the development and maturity of fruits,and the content of organic acids and related enzymes could be increased to varying degrees by 2,4-D treatment.(3)On the whole,the IAA content of the treatment and the control increased first and then decreased,and there were significant differences between the treatment and the control during the whole development period,and the 2,4-D treatment could significantly increase the IAA content of C.humilis fruit.(4)Correlation analysis showed that the uptake rate and relative-growth uptake rate of water-soluble calcium were significantly positively correlated with NAD-MDH activity,malic acid and organic acids contents,and negatively correlated with IAA content,NADP-ME activity and citric acid content.The uptake activities of pectin calcium,active calcium and total calcium were significantly positively correlated with IAA content,NADP-ME activity and citric acid content,and negatively correlated with NAD-MDH activity,malic acid and organic acids content.2,4-D treatment increased the correlation between calcium uptake and citric acid content.In conclusion,2,4-D treatment can increase the calcium uptake capacity,organic acid metabolism and IAA content in C.humilis fruit.With the enhancement of NAD-MDH activity,the contents of malic acid and organic acid increased,which would promote the uptake of water-soluble calcium,but decreased the uptake capacity of pectin calcium,active calcium and total calcium,while the increase of citric acid and IAA content would reduce the uptake of water-soluble calcium,and promote the uptake of pectin calcium,active calcium and total calcium.The 2,4-D treatment regulated the calcium uptake of fruits by increasing the metabolism of organic acids and the content of IAA.