Effect of Soil pH on the Growth, Photosynthesis and Mineral Element Content Concerning Own-Rooted Seedlings and Grafted Seedlings of Blueberry

The adaptation of blueberry to higher soil pH is poor. To explore the effect and probable mechanism of the adaptation of grafted blueberry (Vaccinium spp.) seedlings to the soil environment with higher pH value. We took three types of seedlings, (i)own-rooted Wufanshu (V. bracteatum), an economical shrub belonging to the same genus and family with blueberry, also known as oriental blueberry, (ii)own-rooted ‘Sharpblue’, a southern highbush blueberry (V. corymbosum) cultivar, and (iii) grafted-bluebedrry as experimental materials, which were grown in quartz sand medium for 90 d, irrigated with nutrient solution of three levels of pH values, respectively, i.e. pH 4.6, pH 5.8 and pH 7.0. Results showed that root development, shoot growth and dry biomass accumulation of grafted blueberry were significantly better than those of own-rooted blueberry grown in higher pH medium; compared with own-rooted blueberry seedlings, leaf chlorophyll content, chlorophyll a/b ratio, chlorophyll fluorescence chemical efficiency and photosynthetic efficiency of grafted blueberry seedlings grown in higher pH medium were all significantly improved. Results also showed that mineral element content of leaves, especially Mg and Fe elemental content of grafted blueberry was significantly higher than that of own-rooted blueberry seedlings grown in higher pH media. Grafting-propagation of blueberry seedlings taking Wufanshu as rootstock significantly enhanced the adaptation of blueberry to soil environment with higher pH value.