| Feicheng peach has high economic value, but there exists problems in Feicheng peach production such as browning, poor storability. Calcium fertilizer is an effective measure to reduce the fruit physiological diseases. A field experiment was conducted to determine effects of spraying different forms of calcium fertilizer on total calcium content dynamic, calcium components dynamic and subcellular distribution of Feicheng peach to understand the rules of absorbing calcium and provides the theoretical basis in adding calcium nutrient and technical guidance. Samples of peach at the same ripeness were taken to determine the fruit qualities.The fruit qualities change during storage was observed. The experimental material is 11 years old Feicheng peach tree. Calcium fertilizer was sprayed on selected Feicheng peach fruit trees every 30 days since one month after florescence. Three treatments were carried out in a field experiment:(1) spray 0.5%(Ca content) Amino acid-Ca solution,(2) spray 0.5% Ca(NO3)2solution,(3) spray 0.5% sugar alcohol-Ca solution,(4) spray water. The main results are as follows:1. For the new shoots and leaves,the absorption of calcium is the fastest at the rapidly growing period. The change of total calcium content is the most obvious at this period. From April 28 to May 28, the total calcium content of new shoots under different treatments increased by 44.2%-66.7%. In perennial branches, the calcium content change is not noticeable. Thus the rapidly growing period of new shoots and leaves is the best time for foliage application of calcium.2. Calcium content is the highest in young fruit stage fruits. The total calcium content,water soluble calcium content and pectate calcium content show downward trend with the maturity of the fruit, Spraying calcium treatment increased the total calcium content of the skin, flesh, stone, seeds, and the calcium of flesh has the most significant change. In fruit mature period, the calcium content of flesh treated by Amino acid-Ca solution and Ca( NO3) 2 solution increased by 68% and 77%. The absorption of calcium mainly concentrated in young fruit stage. Spraying calcium in different periods can supply calcium nutrition to Feicheng peach, especially in the fruit enlargement stage. In this stage, it isdifficult to absorb calcium nutrient from the tree, and spraying calcium nutrient can maintain calcium content at a high level.3. Calcium treatment in a certain extent, improved the content of each components of calcium. Water soluble calcium, pectate calcium content and total calcium content had a close relationship. Spraying calcium treatment increases water soluble calcium content and pectate calcium content, so that there have more active calcium in cell. By electron microscope, the pulp cells under calcium treatment show that calcium uniformly distributes on the cell wall,cell membrane, vacuole membrane, and accumulates in vacuole calcium; The pulp cells without calcium treatment show decrease of calcium content on cell wall, and calcium uniformly distributed on cell membrane, vacuole membrane; Browning pulp cell shows that calcium distributed rarely and uneven. Spraying calcium treatment had influence on the subcelluar calcium distribution. Spraying calcium treatment increased calcium distribution in the cell walls, and made calcium distribution uniform so that there is plenty of calcium to maintain the structure and function of cell wall and plasma membrane.4. Spraying calcium treatment increased the total pectin content by 15%-32%. The PE activity was inhibited and the firmness was increased. The calcium supply maintains the physiological activity of cells and thus improves the fruit storage quality.Spraying different calcium had different effects on flavor quality. Calcium amino acid treatment increased the sugar-acid ratio and 6 kinds of aroma substances, calcium nitrate decreased the sugar-acid ratio and 1 kind of aroma substances and calcium chelate treatment decreased the sugar-acid ratio and increased 6 kinds of aroma substances. Spraying amino acid calcium and sugar alcohol calcium can improve the fruit quality. |
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