Study On The Occurred Law And Main Causes Of Spongy Tissue Disorder Of Zihua Mango (Mangifera Indica L.) Fruit

'Zihua' mango (Mangifera indica L.) was experiment material to study the law of spongy tissue disorder and the effect of Ecological factors, mineral elements and enzymes on the occurred rate of the mango fruit spongy tissue, The objects of the thesis expected to further explore the law of the mango fruit disorder and the main causes, and provided some new theretical basis for further research of the mango fruit disorder. The main results of this research as follows:1. The results of investigation showed, the disease rate of spongy tissue of Zihua mango fruit was different in the diffeent area. The disease rate (31%-34%) of spongy tissue in Nanning area was higher than those(28%) in Baise area. Zihua mango was infected two disorders of spongy tissue and flesh break-down in the different area, which the disease rate was 28%-34% and 5%-10% respectively. From the parts of fruit disease to see, the disease rate of the mid-pulp is the highest, then is the top, the last is the botton. The results of investigation indicated also that there was a deep relationship between spongy tissue and cultivars.2. The analysis result of elements for disease fruits and normal fruits showed that the content of K and Mg element in the disease fruits was more than those in the normal fruits, and the content of N, Ca and P element was less than those in normal fruits. Compared with the normal fruits, the content of N, Ca and P element in the disease fruits decreased 24.6%, 12.9% and 3.8% respectively. But the content of K and Mg element increased 40. 1% and 26. 8% respectively.3. The results of experiment showed that there was very significant difference level for daily average values of sap flow rate of the tree among Zihua, Tainong. NO.1 and JinSui from mid-May to mid-June. Therefore, it was very significant difference level between Zihua mango, Tainong NO. 1 and Jinsui mango. Daily average values of sap flow rate of the tree of Zihua mango and Tainong NO. 1 in the late-May reached to 582.0 and 452.0g/hr respectively, and in the mid-June reached to 617. 3 and 503. 9g/hr respectively. Sap flow rate of Zihua mango was the most. It indicated that the ability of absorption water for Zihua mango was more than those of Tai' nong NO. 1 and Jinsui mango.4. There was very significant difference level for transpiration rate of fruit between Zihua and JinSui mango. The transpiration rate of Zihua fruit was the least in three cultivars. Compared with Zihua mango, the transpiration rate of Jinsui mango and Tai' nong NO. 1 increased 41.10% and 51. 03% respectively. For zihua mango, the higher sap flow rate and the lower transpiration made easily deficient of fruit calcium element, and caused the spongy tissue disorder.5. Transpiration rate of fruits by immersing vaslin treatment was less than control in each period, there was significant difference between treatments and control (the average value of treated and control fruits was 1. 0321gH₂O/kgh and 1.7573 gH₂O/kghr respectively). Disease rate of treatment was 27.78%, but the control was 18. 89%. The results showed that vaslin treatments may decreasd fruit transpiration rate and increased disease rate of spongy tissue. There is negative" correlation between transpiration rate and disease rate.6. The results of spraying CaCl₂ treatment showed that the the calcium Ca content of mango fruit increased after spraying CaCl₂, on the other hand, the absorption of N, P, K and Mg elements was restrained, N/Ca, P /Ca, K/Ca, and Mg/Ca decreased, especially for N and K element. In the different treatments, 1.2%CaCl₂ treatment is the best for the effect of decreased the rate of spongy tissue disease.7. The induction disease experiment with enzyme and EGTA showed that all treatments caused the inter-breakdown and soften of fruit pulp. With pectolase treatments, fruit pulp softened seriously. With cellulase treatments caused soften, and was similar to the pectolase treatments, the cavity symptom was similar to the spongy tissue in natural condition. But the amylase and EGTA treatments can only promote aggravating soften. For different concentration pectolase, the cellulase and EGTA treatments, the higher concentration was, the more serious soften was.