| Cucumber(Cucumis sativus L.) as an important gourd vegetation,which is widely cultivated in Yangtze River Valley and the south of Yangtze River Valley. In recent years,cucumber can now grow all around the year owing to the development of cultivation facilities. During the growth, cucumber often encounters many adversities, such as hyperthermia, hypothermy, insect, which become the main reason restricting high and stable yield of cucumber. Grafting is an effective way to enhance the resistance of cucumber, and has been widely used in its production.Cut-grafting developes from insert-grafting and it is a new kind of grafting with high efficient, high survival rate, strong and neat. By now, Hua Zhong Agricultural University has developed efficient cut-grafting system which could be used for factory production for cucumber and watermelon. Researches on cut-grafting physiology mainly focus on seedling stage, but few on whole-life stage. What’s more, there is no report on the effects of different cultivating seasons on cut-grafting cucumber physiology. In this experiment, we employed root-cut-grafting and insert-grafting using Pumpkin (Cucurbita moschata D)’Chuanzhan NO.1’as rootstock and Cucumber(Cucumis Sativus L) ’Chuancui NO.1’as scion. Soil cultivation was adopted in summer and solution and ground substance in autumn. We compared growth and physiological and biochemical characters of the grafted and own-rooted seedlings, which may provide theory for grafting cucumber production in summer and autumn. The main results are as following:1. In summer, length and number of leaves of grafted seedling are significantly higher than that of own-rooted seedling (CK) after one month. After a period of time, the stem of grafted seedlings is significantly wider than that CK ones. But at the later stage, the stem of the CK are significantly wider than that of cut-grafting seedlings, in addition, cut-grafting ones are wider than insert-grafting ones.Grafting significantly increased leaf net photosynthetic rate (Pn) during all stages. Pn of cut-grafting seedlings is little higher than that of insert-grafting in the initial bloom stage and fruiting period. The trend of Gs and Tr accord with Pn, while Ci shows opposite change to Pn. Grafting significantly postpones the first female flower flowering time for 1-2 days, but increases its 1-2 nodes.Compared with own-rooted seedlings, after cut-grafting and insert-grafting, the yields of goods melon increase by 18.84% and 14.28% respectively, and the numbers of goods melon increase by 7.40% and 14.56% respectively. Grafting decreases the mortality rate of cucumber in field. The effect of cut-grafting and insert-grafting is not significant.2. In autumn, all the growth indexes of the grafted seedlings are higher than CK after a period time of planting. However the length of main vines and the number of leaves in cut-grafting seedlings are significantly lower than insert-grafting, the leaves square is little, but the stem is significantly wider at the later stage. During seedling period, the content of photosynthetic pigment Chla, Chlb, Chl(a+b) and Car is lower than CK, but this situation goes to the opposite at the initial bloom stage and fruiting period. The Pn of insert-grafting is higher than cut-grafting during seedling period, but the result in initial bloom stage and fruiting period is opposite.What’s more, stomatal conductance (Gs) and transpiration rate (Tr) show the same change as Pn, but intercellular CO2 concentration (Ci) is contrary to Pn. When temperature is preferable, the activity of POD and CAT of insert-grafting is lower than CK, but activity of SOD, POD and CAT is higher when the temperature is sub-preferable, which enhances cucumber adaptability to sub-preferable temperature.Insert-grafting postpones flowering time of the first female flower, and rises the location of the first flower node. Compared with CK, cut-grafting and insert-grafting increase the yields of goods melon by 59.27% and 64.56%, respectively, and the numbers of goods melon by 28.55% and 34.51% respectively. Grafting significantly decreases water and vitamin content of the fruit, and increases the soluble solid content, soluble sugar and nitrate nitrogen. The effect of cut-grafting and insert-grafting on the cucumber is insignificant. But no matter grafted or not, the content of nitrate nitrogen in the fruit is far lower than vegetable pollution standard, and do not influence the food safety.In conclusion, the grafted cucumber seedlings is superior to cucumber self-rooted seedings; Cut-grafting is slightly better than insert-grafting in summer cultivation, while insert-grafting is slightly better than cut-grafting in autumn cultivation. However there is no significant difference between these two methods. |
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