硫酸锌对苹果叶片光合产物的合成及其向果实运输的影响

Effects of ZnSO_(4) Levels on the Photosynthate Synthesis and Its Translocation to Fruit in Apple

为明确叶面施硫酸锌对苹果叶片光合产物合成及其向果实转移分配的影响机理,进而为生产上在苹果果实发育关键时期通过叶面补锌的措施提高果实品质提供理论依据,以8年生寒富/GM256/山定子为试材,设置0(CK)、0.1%(ZS1)、0.2%(ZS2)、0.3%(ZS3)和0.4%(ZS4)5种不同浓度硫酸锌处理,采用^(13)C同位素标记技术,结合相关生理生化指标测定,研究叶面不同浓度硫酸锌对果实膨大期苹果叶片^(13)C光合产物的合成及其向果实运输的影响。结果表明:随着叶面施锌浓度的增加,叶片Rubisco酶活性、净光合速率、PSII最大光化学效率、PSII实际光化学效率、光化学淬灭系数、PSII电子传递速率、山梨醇和蔗糖含量、6-磷酸山梨醇脱氢酶和蔗糖磷酸合酶活性及果实山梨醇脱氢酶和酸性转化酶活性均呈现先升高后降低的趋势,且均以ZS3处理最高(其值分别为8.56μmol·min^(-1)·g^(-1)、15.84μmol·m-2·s-1、0.838,0.751,0.843,92.1,35.41mg·g^(-1)FW、5.25mg·g^(-1)FW、412.99μg·min^(-1)·g^(-1)、420.87μg·min^(-1)·g^(-1)、7.19μmol·h-1·g^(-1)FW和9.25μmol·h-1·g^(-1)FW),CK处理最低。^(13)C示踪结果表明,各处理果实^(13)C含量随时间增加逐渐增高,而果实^(13)C转运速率则随时间的增加逐渐降低。与其他处理相比,ZS3(0.3%ZnSO_(4)·H_(2)O)处理显著提高了叶片^(13)C光合产物向果实运输速率,同时该处理下果实^(13)C含量最高。综上表明,叶片涂抹适宜浓度硫酸锌(0.3%ZnSO_(4)·H_(2)O溶液)处理优化了叶片光合性能,提高了苹果叶片光合同化物的合成能力,提高了源叶的生产力;同时提高了果实糖代谢相关酶活性,提高了果实库强,增强了果实对光合同化物的竞争力,促进了叶片光合产物向果实的输送。

To explore the effects of zinc levels on the synthesis and translocation of photosynthate from leaves to fruits,and to lay a theoretical foundation for improving fruit quality through zinc supplementation during the critical period of apple fruit development,a field experiment was carried out in eight-year-old Hanfu/GM256/Malus baccata apple trees with using^(13)C tracer method to examine the effects of different zinc levels(ZnSO_(4)·H_(2)O 0,0.1%,0.2%,0.3%,0.4%,expressed by CK,ZS1,ZS2,ZS3,ZS4)on the translocation of photosynthate to fruit during fruit rapid-swelling.The results showed that Rubisco enzyme activity,net photosynthetic rate,maximal photochemical efficiency of PSII,actual photochemical efficiency of PSII,coefficient of photochemical quenching,sorbitol and sucrose content,sorbitol 6-phosphate dehydrogenase,sucrose phosphate synthase enzyme activities of leaves and sorbitol dehydrogenase,acid interase enzyme activities of fruits showed a trend of first increase and then decrease with the increasing of zinc levels,all of them reached the highest under ZS3 treatment(8.56μmol·min^(-1)·g^(-1),15.84μmol·m-2·s-1,0.838,0.751,0.843,92.1,35.41 mg·g^(-1)FW,5.25mg·g^(-1)FW,412.99μg·min^(-1)·g^(-1),420.87μg·min^(-1)·g^(-1),7.19μmol·h-1·g^(-1)FW and 9.25μmol·h-1·g^(-1)FW).The^(13)C tracer results showed that each treated fruit^(13)C content gradually increased along with the treated time,while the fruit^(13)C transport rate gradually decreased.The treatment of 0.3%ZnSO_(4)·H_(2)O significantly increased fruit^(13)C content and the transport rate of photosynthate from leaves to fruits as well as the content of soluble sugar during fruit ripening,compared with other treatments.Our results indicated that foliage application of ZnSO4 solution(0.3%ZnSO_(4)·H_(2)O)enhanced leaf photosynthesis and sugar metabolism level,improved the ability of leaf assimilate synthesis and transportation,the strength of fruit bank,and consequently promoted the directional transportation of sugar to fruit.