叶施钙、硼对苹果果实糖含量及叶片矿质元素的影响

为探究叶面喷施Ca、B后苹果果实糖含量和叶片中P、K增加的原因,分别以20年生富士/八楞和一年生的富士/SH6嫁接苗为试材,前者在座果期(盛花期后10d)叶面喷施10.00g/L的CaCl_2、果实迅速生长期(盛花后85d)叶面喷施1.05g/L的Na_2B_4O_7,之后测定叶片光合作用、叶片与果实的矿质元素及相关糖含量、叶片6-磷酸-山梨醇脱氢酶(S6PDH)活性;后者在嫁接苗长到6月时叶面分别涂抹10.00g/L的CaCl_2和1.05g/L的Na_2B_4O_7,之后测定叶片光合作用、矿质元素。结果显示:1)喷施Ca、B后,从盛花后85d开始,叶片S6PDH活性增强、山梨醇含量增加,果实中的果糖和总糖含量在生长后期也显著增加;2)Ca、B处理后,叶片净光合速率、蒸腾速率和气孔导度显著加强;3)在涂抹Ca、B后,叶片中其他矿质元素Mn、Zn、Cu、K也显著增加。上述结果表明,喷施Ca、B能够提高苹果叶片光合作用,进而通过增加光合产物来提高果实的糖含量;Ca、B加强了叶片蒸腾作用,使得其他矿质元素可能随着蒸腾流运输到叶片而得到增加。

Effect of foliar B and Ca on fruit sugar and leaf minerals in apple

To explone the reason why the sugar in fruit and P,K in leaf were increased in apple,20-year-old Fuji/Baleng and 1-year-old Fuji/SH6 were chosen as experimental materials,the former was treated with leaf spraying 10 g/L CaCl₂ at fruit set stage (10 days after full bloom) and 1.05 g/L Na₂B₄O₇at rapid fruit growth stage (85 days after full bloom).Minerals and soluble sugars in leaves and fruits,photosynthesis and 6-phosphate-sorbitol dehydrogenase (S6PDH) activity were analyzed after foliar application of Ca or B.The latter one was treated with leaf daubing 10 g/L CaCl₂and 1.05 g/L Na₂B₄O₇,photosynthesis and minerals in leaves were analyzed afterwards.The results showed 1) Leaf spraying Ca or B resulted in a significant increase in S6PDH activity from 85 days after full bloom,accompanied with the increase of leaf sorbitol concentrations.Subsequently,fruit fructose and total soluble sugar contents were significantly increased at later growth stage.2) Net photosynthesis rate,transpiration rate and stomatal conductance of B/Ca-applied-leaves were significantly increased.3) Mn,Zn,Cu and K contents of potted apple trees after the application of CaCl₂ and Na₂B₄O₇·10H₂O were significantly increased.The results indicate that leaf spraying of Ca and B can induced a dramatic increase in sugar content of fruit by improving apple leaf photosynthesis.The increase in leaf mineral elements levels after foliar application of Ca or B may be associated with the increase of transpiration.