Effect Of Spraying Fulvic Acid And Glyeinebetaine On Drought Resistant Physiology As Well As Fruit Yeild And Quality Of Two Malus Species

The Loess Plateau is one of the major apple-growing areas in China, its acreage and production rank the first in our country. Water shortage occured frequently due to seasonal uneven distribution of annual rainfall, which limited the improvement of yield and quality of apple(Malus pumila). Numerous researches showed that exogenous regulations substances application, such as fulvic acid(FA) and glyeinebetaine(GB), could improve plant drought resistance as well as yield and quality of fruit. However, most studies focused on the promoting effect under single treatment and there were less studies of synergistic effects between two or more kinds substances combination. In this study, the pot and field experiments respectively using M.hupehensis(Pamp) Rehd and Malus pumila cv. Fuji as materials, were conducted to explore the influence of spraying single and mixed of FA and GB using on drought resistance physiology, leaf nutrition as well as yield and quality of fruit. The main conclusions are as follows:1. Under drought stress, relative water content(RWC), soluble sugar content and photosynthetic pigments content of M.hupehensis(Pamp) Rehd leaf were decreased. But malondialdehyde(MDA) content were increased. The exogenous single and combinated application of FA and GB both could increase osmotic adjustment substances content, such as soluble protein, proline and soluble sugar content. It’s also exhibited increases in the activities of superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT), with a decrease in MDA content. Moreover, application of FA and GB could increase leaf relative water content, net photosynthetic rate(Pn) and water use efficiency(WUE). Therefore, exogenous FA and GB could reduce the damage degree of Malus and promote its growth and development. The effect of combination of them were better than their single treatment.2. The principal component analysis indicates the importance order: MDA content>soluble protein content>CAT activity>POD activity >chlorophyll content >proline content>parotenoids content >SOD activity >RWC>soluble sugar content > Pn. Moreover, the plant under 200 mg·L-1 FA treatment obtained the greatest stress resistance in M.hupehensis(Pamp) Rehd using membership function analysis. There had a significant difference on MDA content and activities of SOD, POD and CAT under FA treatment. It showed a significant difference on soluble sugar content, soluble protein content, proline content under GB application. Meanwhile, it showed a great promoting interaction between FA and GA on MDA content and activities of SOD, POD and CAT.3. The single and combination treatments of FA and GB both improve the leaf nutrition as well as fruit yelid and quality of Fuji apple in different degree. The content of soluble sugar, total nitrogen, total phosphorus, total potassium, fruit quality, fruit weight, fruit firmness, soluble sugar content, soluble protein content and vitamin C content were gradually increased with the increasing of FA or GB concentration. The effect of combination treatment of FA and GB were more obvious than those of their single treatment.The compartion studies were carried out to clarify the different effects of GB and FA, and their interaction to drought resistance physiology, leaf nutrition, fruit yield and quality of Fuji apple. In conclusion, the best treatment of them were: FA 200 mg·L-1 conbination with GB 100 mg·L-1.Our work might contribute to a simple and pratical measure to increase drought resistance physiology, as well as yield and quality of apple in dryland orchard on the Loess Plateau.