Effects Of The Double-Stock Grafting On The Physiological Characteristics, Yield And Quality Of Cucumbers

Cucumber (Cucumis sativus L.) is one of the most important vegetable in the world. Grafting, an effective measure to improve resistantance and overcome continuous cropping obstacles of melon and fruit vegetables, has been widely applied in cucumber production recently. But the traditional grafting is set up on the base of the Single-grafting.Because of the resource limitation of rootstock, the roles of many rootstocks have specificity or uniqueness. For example, the fig leaf gourd as rootstock can enhance the resistantance and improve the yield of the scion, but the marketability and quality of which are decreased. So in this experiment, double-stock grafting was adopted with cucumber as scion, figleaf gourd(Cucurbita ficifolia), a rootstock that can enhance stress resistance and'Jingxin No.5', a rootstock that can improve quality as rootstocks, and we compared the double-stock grafting with single-stock grafting and scion-root seedling to study the effects of double-stock grafting on the physiological characteristics, yield, and quality of cucumber under the different nitrogen levels and simulating drought stress conditions. The results were as follows:1. The double-stock grafting possessed the excellent characteristics of Jingxin and Heizi. Both single and double grafting improved the absorption of water and fertilizer, increased water and fertilizer use efficiency, and promoted plant growth. The yield and fruit numbers per plant of double-stock were distinctly higher than that of the single-grafting of Jingxin and scion-root treatments. The double-stock grafting could distinctly increase the content of solution sugar, which the content of Vc and sugar-acid ratio were distinctly higher than Heizi and scion-root treatments. Double-stock grafting also could shorten the ruit stalk length cased by single-stock grafting.2. The double-stock grafting was better than Single-stock or leaned to the better one. The change trend of water, Ca and P use efficiency, yield, fruit numbers, and dry matter content of different treatments rised in the first, and declined in the follow with the increase of the nitrogen levels. The chlorophyll, nitrate reductase activity, Mg, titratable acid, protein, and nitrate rised gradually, but N use efficiency and soluble sugar were decreased gradually. There is no significant effects on K and Vc use efficiency. The water and fertilizer use efficiency, yield, and fruit number of double-stock and Jingxin treatments were better at low nitrogen level, but the double-stock and Heizi treatments were better at high nitrogen level. The plant growth of double-stock and Heizi treatments were better, and the nutritional quality of double-stock and Jingxin treatments were better at the different nitrogen levels.In addition, the nitrate content of double-stock treatment was lower than that of the single-stock.3. The drought-resistance of double-stock was higher than single-stock under simulating drought stress. The double-stock could promote plant growth. Compared with the single-stock treatment, the double-stock treatment has lower the free water/bound water ratio, and it is water content declined in the first, fllowed by an increased, while the water content of scion-root shoeed sustained decreased. The descent range of photosynthetic pigment was smaller than the that of the scion-root group. The soluble sugar and Pro content of double-stock were smaller than Single-stock and own-root after stress. Grafting treatments had no significant effect on MDA content, while the scion-root treatment increased by 108.95% at 14 days after stress.