The effect of soil pH on plant growth, leaf chlorophyll fluorescence and mineral element content of two blueberries

Soil pH is a key factor affecting the growth of blueberry, and most soil in China is difficult to grow blueberry because of the high soil pH. Therefore, the study on the reaction mechanism of blueberry to different soil pH is beneficial to breeding new cultivars to adapt to different soils with excessive pH. Research was conducted to study the effect of different soil pH (4.5, 5.3, and 6.0) on plant growth, chlorophyll fluorescence, and leaf mineral element content in two bluebrerries, Vaccinium virgatum 'Climax' and V. corymbosum A119, an excellent seedling progeny from the southern highbush blueberry cultivar 'Southmoon'. Plant height, stem-base diameter, branching number, leaf dry weight, stem dry weight, root dry weight, chlorophyll content index, PSII maximum photochemical efficiency and effective light quantum yield showed decreasing trends with increased soil pH in the two blueberries. However, less reduction was found in A119 than 'Climax'. Leaf Fe and Mn contents of 'Climax' and A119 decreased as the soil pH increased, whereas K, Ca and Mg contents increased. P contents decreased in 'Climax' and remained fairly constant in A119 as the soil pH levels increased. Cu and Zn contents were unaffected irrespective of pH in the two blueberries. In total, A119 had greater high pH tolerance than 'Climax', and the disorder of leaf mineral element content could be a key factor to inhibit the growth of blueberry when the soil pH was increased.