叶果比和摘叶方式对苹果13C同化物向果实转运及果实品质的影响

Effect of leaf-fruit ratio and leaf-picking methods on translocation of 13C-photoassimilates to fruit and fruit quality in apple

试验以6年生‘烟富3’/M26/平邑甜茶苹果为试材,采用13C同位素标记技术,研究在果实膨大后期两种摘叶方式下不同叶果比对叶片糖代谢和13C同化物向果实转运的影响。结果表明:摘叶后10 d,不同处理均提高了叶片叶绿素含量、净光合速率、Rubisco酶活性和叶片糖代谢水平,均以T3处理(叶果比30:1且均匀摘叶)下最高。摘叶后20 d,过度摘叶(T1T3处理)降低了叶片光合作用和糖代谢水平,加速了叶片衰老;适度摘叶(T4T6处理)下各项指标均高于摘叶后10 d,均以T4处理(叶果比30:1且只摘除其他叶片)下最高。T4处理下的13C自留量和13C输出量分别达最低和最高水平,分别为60.4%和39.6%。果实13C输入量随叶果比增加呈先增高后降低趋势,以T4处理最高。适度摘叶提高了果实品质。上述发现表明适度摘叶可提高源叶光合作用和糖代谢水平,防止叶片早衰,促进同化物向果实转运,提高果实品质。

13 C trace technique was used to explore effect of different leaf-fruit ratio treatments with two leaf-picking methods on sugar metabolism in leaves and translocation of 13 C-photoassimilates to fruit during late stage of fruit rapid-swelling in six-year-old apple seedlings‘Yanfu3’/M26/Malus hupehensis.The results showed that 10 days after leaf-picking,the chlorophyll content,Pn,Rubisco activity and sugar metabolism level in leaves were increased in all treatment,among them T3 treatment(leaf-fruit ratio 30:1 and uniform leaf-picking)showed the best performance.Twenty days after leaf-picking,excessive picking leaves(T1–T3 treatments)reduced Pn and sugar metabolism level in leaves and accelerated leaf senescence,while the indexes under moderate leaf-picking(T4–T6)treatments were higher than 10 days after leaf-picking,which were the highest in T4 treatment(leaf-fruit ratio 30:1 and only picking other leaves).The 13 C self-retention and output reached respectively the lowest(60.4%)and highest(39.6%)levels in T4 treatment.The 13 C absorption in fruits was first increasing and then decreasing with the improvement of leaf-fruit ratio and it was the highest in T4 treatment.Moderate leaf-picking improved fruit quality.All these results indicated that the moderate leaf-picking increased Pn and sugar metabolism level of source leaves and prevented premature senescence of leaves,which promoted the transportation of more photoassimilates to fruits and improved fruit quality.