The Effect Of Different PH Solution On Blueberry Growth And Fruit Quality

Blueberry (Vaccinium corymbosum) fruits are rich in minerals, vitamins and other antioxidants anthocyanins, thus attract many domestic and foreign consumers. Blueberries grow mostly in the northern China, but blueberry introduction and cultivation history is short with less varieties in the south. Climate is warm and humid, and rainfall is abundant, soil is mostly acidic in the south, which are benefit for planting blueberries. In this study Premier and Misty were uesd as experiment materials, which are two introduced varieties of blueberries in Changsha. To irrigate potted blueberries, H2SO4, Al2(SO4)3 and NaOH were used to prepare solutions of pH 4.5,5.5,6.5,8.5, in which pH 7.0 is the control group (CK). The morphological, physiological and biochemical indicators, leaf nutrient contents, photosynthesis and fruit quality and other indexes of blueberry plants were measured to explore the impact of different pH values on the growth and fruit quality of introduced blueberries. Our results provided relevant technical supports for blueberries cultivation and promotion in Hunan regions and other southern area. The main results are as follows:(1) From pH7.0 to pH4.5, with acidity increaseing, Premier and Misty’s the growth of were promoted, and Growth-promoting effect in Premier was better; but in alkaline (pH8.5) environment, Premier and Misty growth was severely inhibited death. Compared with CK at pH4.5, the growth of Premier increased 31.8%, diameter increased 76.19%, crown increased 25.02%, inflorescence length increased 27.78%, number of flower buds increased 38.89%, fruit diameter increase 37.50% and fruit length increased 34.21%; Misty height increased 21.83%, diameter increased 1.5%, crown increased 20.67%, inflorescence length increased 17.92%, number of flower buds increased 21.57%, fruit diameter increased 12.99%, and fruit length increased 16.18%.(2) From pH7.0 to pH4.5, Premier and Misty’s SOD, POD, CAT activity and soluble sugar content with enhanced acidity increases, but MDA content was decreasing; Premier upgrade is better. Compared with CK at pH4.5, Premier’s SOD activity increased 99.50%, POD activity increased 137.78%, CAT activity increased 176.51% and soluble sugar content increased 33.67%, while the MDA content decreased 51.07%; Misty’s SOD activity increased 151.74%, POD activity increased 49.29%, CAT activity increased 56.19% and soluble sugar content increased 18.10%, while the MDA content decreased 55.07%.(3) From pH7.0 to pH4.5, with acidity increasing, Premier and Misty’s leaves N, P content was rising, while the K element content decreased; Premier upgrade is better. Compared with CK at pH4.5, Premier leaves N element content increased 28.02%, P element content increased 192.16%, K element content decreased 36.47%; Misty leaves N element content increased 20.81%, P element content increased 69.05%, K element content decreased 51.77%. Compared with the acidic environment, when they were in alkaline environment, two blueberry leaf N and P element content was low, but K element content higher.(4) From pH7.0 to pH4.5, with acidity increasing Premier and Misty’s chlorophyll content, leaf area and specific leaf weight as well as the photosynthesis indexes showed upward trend; but indexes were declining in alkaline environment. At pH4.5 compared with CK, Premier chlorophyll content had increased greatly, specific leaf weight increased 39.68%, leaf area increased 45.61%, while photosynthesis indexes had improved greatly; Misty chlorophyll content also had relatively great promotion, specific leaf weight increased 17.93%, leaf area increased 4.15%, and photosynthesis indexes enhanced greatly.(5) From pH7.0 to pH4.5, with acidity increasing, Premier and Misty’s fruit anthocyanin content, soluble sugar content and SOD activity showed an upward trend in with; Misty quality of fruit enhanced better. Indexes meet the minimum in alkaline environmental. Compared with CK at pH4.5, Premier fruit anthocyanin content increased 115.38%, soluble sugar content increased 32.99%, SOD activity increased 62.07%. Misty fruit anthocyanin content increased 211.54%, soluble sugar content increased 28.82%, SOD activity increased 73.62%.(6) When Premier and Misty were planted in the soils treated with H2SO4 or Al2(SO4)3, the physiological and biochemical and fruit quality index had no significant difference at both treatments in the same pH. But the photosynthesis under H2SO4 treatment was higher than under Al2(SO4)3.