摘要
【目的】明确猕猴桃耐硒能力,深入探索喷施时期和硒源对猕猴桃各部位硒含量、累积分配、有机转化及品质的影响,以期为富硒猕猴桃的生产提供理论依据。【方法】以‘金桃’猕猴桃为试验材料:试验一,选取Na_2SeO_3和Na_2SeO_4为硒源,分别设50、100、200、300 mg·L^(-1)4个硒水平,均于幼果期喷施;试验二,基于试验一研究结果,分别于幼果期、膨大期和糖分累积期喷施100 mg·L^(-1)两种硒源。【结果】当两种硒源喷施质量浓度>100 mg·L^(-1)时,猕猴桃树出现叶片变黄、焦枯等中毒症状。果肉硒含量随喷施时期后移而显著降低,但果皮中硒含量呈现出相反的变化趋势。Na_2SeO_4处理下,猕猴桃果实各部位硒含量是Na_2SeO_3处理的1.1~1.8倍。无论何时喷施何种硒源,果肉和果皮的硒有机化率分别可超过60%和75%。叶面施硒可通过可溶性固形物和维生素C含量的增加、可滴定酸含量的降低,提升猕猴桃的品质。【结论】硒酸盐富硒效果较好,喷施时期后移,猕猴桃果肉硒累积占比下降。
【Objective】Selenium(Se) is recognized as an essential micronutrient for humans and animals as a crucial component of glutathione peroxidase(GPX). As a new type of fruit in the twenty-first century, kiwifruit is more and more favored by the majority of residents. Consuming Se-rich fruit may serve the dual function of supplementing selenium nutrition and regulating diet structure. However,there are rare reports about the Se enrichment capacity of the kiwifruit. Therefore, this study aims to: 1)determine the maximum Se tolerability of the kiwifruit tree by foliar spraying different concentrations of Se, and 2) further explore the effects of spraying stage and Se source on the Se concentration, cumulative distribution and conversion, as well as on fruit quality.【Methods】Here,‘Jintao'kiwifruit(Actinidia L.) was used for the experiments. The experiments were performed in the villages of Changliang, Jianshi county, Hubei, China. The soil was yellow brown, with pH 5.20, organic matter 12.17 g· kg-1, alkali-hydrolyzable nitrogen 75.30 mg · kg-1, available phosphorus 10.40 mg · kg-1, available potassium110.54 mg· kg-1, and total Se 22.35 μg· kg-1. The planting density of kiwifruit trees was 1 200 plants· hm(-2).In Experiment Ⅰ, Na2SeO3 and Na2SeO4 were selected as Se sources. There were four Se levels of 50,100, 200 and 300 mg· L(-1) and spray volume was 1 000 L· hm(-2). Spray was conducted in the young fruit period(June 23, 2016), and spraying clear water was used as the control group. In Experiment Ⅱ, in2017, based on the results of Experiment Ⅰ, in the same orchard, Na2SeO3 and Na2SeO4 were sprayed at100 mg· L(-1) separately in the young fruit stage(June 25), the expanding stage(July 31) and sugar accumulation stage(September 16). The equal amount of clear water was applied at different stages as control. The experiment consisted of a total of 9 treatments, which were randomly arranged with three replicates. Kiwifruit samples were divided into peel and flesh for analyses of Se content, accumulation and distribution and quality parameters(moisture content, vitamin C, soluble solids and titratable acids). Values obtained from different treatments were subjected to ANOVA. Separation of means was performed on multiple range tests using the SPSS 20.0. Origin 2017 and Excel 2016 were used to generate graphs and tables, respectively.【Results】Spraying Na2SeO3 and Na2SeO4 significantly increased Se concentration in the leaves and branches and the increment increased with the increase of Se concentration. When the concentration of was over 100 mg· L(-1), leaves turned yellow with withered edge withered and other toxic symptoms. In both Se sources, Se concentration in the leaves and branches increased as the spraying was delayed. Se concentration in the leaves and branches in the treatment of spraying at sugar accumulation stage was about 3 to 4 times that in the treatment at the young fruit stage. At the same spraying stages, the Se concentration in the leaves and branches sprayed with Na2SeO4 was 1.7-2.3 and 1.2-1.4 folds that with Na2SeO3, respectively. The Se concentration in fruit flesh decreased significantly with the delaying of the spray, but Se concentration in the peel showed an opposite trend. Se concentration in each part of the fruit sprayed by Na2SeO4 was 1.1-1.8 times higher than that by Na2SeO3. Se source had no significant effect on the accumulation and distribution of Se within fruit, but spraying stage had significant effects on the accumulation and distribution of Se in the fruit. Se accumulation reached the highest(52%-58%) when Se was sprayed at young fruit stage, but it decreased by 16%-19% when sprayed in the expanding stage. Selenium was mainly accumulated and distributed in the peel when the spray was conducted at sugar accumulation stage, which accounted for 76%-78%. Spraying stage and Se source had no significant effect on the proportion of organic Se in different parts of fruit. Regardless of Se forms or spraying stages, the organic Se in the flesh and peel could be up to over 60% and 75%, respectively. The foliar application of Se increased the concentration of soluble solids and Vitamin C, reduced the titratable acids and improved the quality of kiwifruit.【Conclusion】For kiwifruit, at a spraying volume of 1 000 L· hm(-2), the highest safe concentration of Se is 100 mg· L(-1). The utilization efficiency of Se in kiwifruit is higher when Se is supplied in Na2SeO4 form than in Na2SeO3 fruit. Se sprayed at early stages is readily transported to the flesh, while after the spraying stage, more Se sprayed is distributed in the peel. Therefore, advancing the spraying with Na2SeO4 is recommended for producing Se-enriched kiwifruit.
作者
邓小芳
吕臣浩
黄立强
张海清
赵竹青
刘新伟
DENG Xiaofang;LV Chenhao;HUANG Liqiang;ZHANG Haiqing;ZHAO Zhuqing;LIU Xin-wei(Microelement Research Center,Huazhong Agricultural University,Wuhan 430070,Hubei,China;Hubei Provincial Engineering Laboratory for New-Type Fertilizer,Wuhan 430070,Hubei,China;Jianshi Soil and Fertilizer Station of Hubei Province,Jianshi 445300,Hubei,China)
出处
《果树学报》
CAS
CSCD
北大核心
2018年第11期1385-1392,共8页
Journal of Fruit Science
基金
中央高校基本科研业务费专项(2662016QD015)
华中农业大学本科生科技创新专项(2017BC013)