Studies On Fruit Calcium Absorption And Supplementing Techniques In Fuji Apple

With many physiologic functions, calcium plays an important role in the process of fruit quality form. For some Ca-sensitive cultivars , however, no ideal way to supplement calcium into fruit has been found so far because of the limitation of knowledge on the pattern of uptake and translocation of calcium. It is necessary, therefore, to pursue the secret involved in calcium metabolism and screen the advanced supplementing techniques for properly adjusting the essential nutrient within the fruit. 45Ca isotopic trace technique was used in the present test with Red Fuji apple to document the amount of absorption and translocation calcium in different parts of whole potted trees, and the effect of several Ca-supplementing approaches was assessed through a series of field trials. The main results are as follows: 1. The amount of calcium varies considerably with different organs, with larger amount allocated in both fruit and new shoots during young fruit growing stage, accounting for 34.79% and 11.31 %, respectively, but mainly in new shoots during fruit swell stage, taking up 44.9 1%. 2. There is an apparent difference in calcium forms among different organs. calcium exists chiefly in an active form during young fruit growing stage, but in an inactive form during fruit swell stage, especially in fruit stems and cluster bases. IAA enables the interchange of calcium forms, increasing soluble and pectic-formed calcium by 1.88 and 1.30 times respectively, thus raising total calcium content in fruit as much as 76.5 1%. 3. The capacity of leaves to calcium to fruit differs from the locations at which leaves grow. The contributing intensity of different leaves is shown in a descending order below: Ist--4th leaves on new shoots bearing on cluster >lst-~ 4th leaves on cluster base near the fruit end>lst?st leaves behind cluster base near the fruit end>Sst?th leaves on new shoots bearitg on cluster. The distribution of calcium migrating from leaves to fruit follows the principle "earest leaves biggest contributors".e., the ability to donate calcium is positively correlated with the distance between fruit and leaves. 37 4 The four injection treatment combinations (15d BF+15d ABF. 15d ABF+30d ABF, 105d ABF+120d ABF, 35d BH+20d BH) could consistently increase the fruit calcium content, with best effect observed from the treatment 15d BF+15d AFB. Among compound combination of calcium citrate and additives, the treatment calcium citrate+IAA showed most effective increasing fruit calcium content by 104.83%. The effect on calcium increase in fruit varied with different ways for calcium applications, with the best treatment being amino-calcium +IAA+B+Zn, increasing fruit calcium content by 94.6 1%. 5 Calcium could raise fruit firmness but the influencing extent depends upon the stage when individual treatment was applied. The two treatment of both 15d BF+15d AFB and 35d BH+20d BH seemed extremely promising in terms of raising fruit calcium content, thus enhancing fruit storage quality markedly.