Growth, Gas Exchange, and Boron Distribution Characteristics in Two Grape Species Plants under Boron Deficiency Condition

The boron (B) deficiency tolerance capacity of two grape materials, ‘Xishui-4’ (Vitis flexuosa) and ‘Crystal’ (V. vinifera × V. labrusca), were evaluated using a potted experiment in order to identify the B-use efficiency of grape and screen B-efficient grape resources. The sterile lines of two genotypes of grape were used as test materials, and a large number of test-tube seedlings were obtained through rapid propagation. The test-tube seedlings were acclimatization and transplanted, and the tested seedlings were treated with B stress after survival. In this experiment, the materials were cultured in nutrient solution, which contained 0.00 (B0), 0.25 (B1), and 0.50 (control) mg·L−1 B concentrations, and the two genotypes of grape seedlings were cultured in vitro. The results were counted after 60 days of culture. The results showed that the B deficiency significantly reduced the growth parameters such as plant height, leaf area, total root length, and dry biomass of the two genotypes, and the inhibition of ‘Crystal’ growth parameters was greater than that of ‘Xishui-4’. Moreover, the B deficiency also affected photosynthesis of the two genotypes, such as decreased leaf photosynthetic pigments, net photosynthesis rate, transpiration rate, stomatal conductance, intercellular carbon dioxide concentration, and stomatal density. Interestingly, the decrease ranges of ‘Crystal’ were greater than those of ‘Xishui-4’, indicating that ‘Crystal’ photosynthesis was more susceptible to B deficiency. Under the control condition, the concentration and accumulation of B in ‘Crystal’ were significantly higher than those in ‘Xishui-4’. However, under the condition of B deficiency, the B concentration, accumulation amount, accumulation rate, utilization index, and tolerance index of ‘Xishui-4’ were higher than those of ‘Crystal’, and the B transport capacity of ‘Xishui-4’ was more stable, indicating that ‘Xishui-4’ had a better tolerance against B-deficient stress than ‘Crystal’ did. Therefore, ‘Xishui-4’ is a plant with strong adaptability to B deficiency stress, which can be used as B efficient grape resources and a genetic improvement of B efficient grape.