赣南脐橙生长发育期果实和叶片矿质营养与重金属元素的动态变化及相关性分析

Dynamics changes and correlation of mineral nutrition and heavy metal elements in fruits and leaves of navel orange during growth and development in Southern Jiangxi

【目的】探索赣南脐橙不同生长发育期果实营养物质含量及果实与叶片中大量元素、微量元素、重金属元素和轻稀土元素的变化特征,并分析果实和叶片中不同元素之间的相关性,为研究脐橙生理代谢和品质形成的调控机理提供依据。【方法】以赣南10年生纽荷尔脐橙为试验材料,自脐橙盛花期后90d(7月)起,每月测定不同生长发育期脐橙果实糖酸含量及果实和叶片中大量元素(N、P、K、Ca、Mg)、微量元素(B、Fe、Mn、Cu、Zn)、重金属元素(Pb、Cr、Cd)和轻稀土元素(La、Ce、Pr、Nd、Pm)等的含量,分析其周年动态变化规律及相关性。【结果】9月份是脐橙果实和叶片矿质营养及重金属元素变化的关键时期。果实纵、横径和单果质量均与生长发育期呈显著正相关,脐橙果实近球形,果形指数为1.04~1.07。柠檬酸是脐橙果实总酸的主要组成成分,最高可达82.76%。叶片矿质营养和重金属元素含量均高于果实。大量元素Ca、Mg和微量元素Cu、Zn是影响果实和叶片矿质营养积累的关键因子,其中Ca可以促进果实Mg和Cu的积累,抑制叶片Mg和Zn积累;Mg与果实Cu和叶片Zn含量呈显著正相关。脐橙果实中未检测出Pb和Cd元素,叶片中Pm与其他4种轻稀土元素含量的变化趋势相反,其在果实发育过程中呈先减少后增大的趋势。B是影响叶片Pm积累的关键因子,能显著促进叶片Pm积累,果实中未检测出Pm;果实和叶片中的La、Ce、Pr、Nd元素之间表现出显著的促进作用。【结论】脐橙果实品质受矿质营养元素的协同影响,其中大量元素Ca、Mg和微量元素Cu、Zn是影响脐橙果实品质的关键因子;脐橙果实品质未受到重金属Pb、Cr、Cd的污染;脐橙叶片轻稀土元素La、Ce、Pr、Nd含量越高,转移积累到果实中的量也越高。

【Objective】To provide basis for studying regulation of physiological metabolism and quality formation of navel orange,this study explored nutrient contents in leaves and fruits of navel orange investigated the changing characteristics of abundant elements,trace elements,heavy metal elements and light rare earth elements,and analyzed the correlation between different elements at different growth and development stages in Southern Jiangxi.【Method】The 10-year-old navel orange trees were selected in this study.From 90 d(July)after blossom,sugar and acid contents in fruits as well as abundant elements(N,P,K,Ca and Mg),trace elements(B,Fe,Mn,Cu and Zn),heavy metal elements(Pb,Cr and Cd)and light rare earth elements(La,Ce,Pr,Nd and Pm)in the fruits and leaves were measured at different growth and development stages.【Result】September was a critical period for changes of mineral nutrition and heavy metal elements in fruits and leaves.There were significant positive correlations between fruits longitudinal diameter,transverse diameter,single fruits weight and growth time.The fruits were near spherical with shape index of 1.04-1.07.Citric acid was the main component of total acids in navel orange fruits,accounting for up to 82.76%.The contents of mineral nutrition and heavy metal elements in leaves were higher than that in fruits.The abundant(Ca and Mg)and trace elements(Cu and Zn)were the key factors influencing the accumulation of mineral nutrition in fruits and leaves.Ca promoted the accumulation of Mg and Cu in fruits while inhibited the accumulation of Mg and Zn in leaves.Mg was positively correlated with Cu in fruits and Zn in leaves.Pb and Cd were not detected in fruits.The trend of Pm was opposite to other four light rare earth elements in leaves.B significantly promoted the accumulation of Pm in leaves,while Pm was not detected in fruits.La,Ce,Pr,and Nd showed a significant promoting effect on each other in fruits and leaves.【Conclusion】The navel orange quality was affected by all mineral nutrient elements,among them abundant elements(Ca and Mg)and trace elements(Cu and Zn)were the key factors.Navel orange fruit quality was not polluted by heavy metals Pb,Cr and Cd.Higher levels of light rare earth elements(La,Ce,Pr and Nd)in leaves would lead to higher contents in fruits.