Complexed calcium sources improve the quality of sour passion fruit seedlings under salt stress

Salinity stress is one of the main limitations to the expansion of sour passion fruit areas in the semi-arid region of Brazil. Studies have shown that the application of calcium reduces the deleterious effects of salinity, especially when sources of rapid availability and absorption are used. The objective of this study was to evaluate the effect of complexed calcium sources on the growth and quality of sour passion fruit seedlings under salt stress. The experiment was conducted in a randomized block design, in a 2 & times; 2 & times; 3 factorial arrangement, relating to two sour passion fruit cultivars (BRS GA1 and BRS SC1), two levels of water salinity (0.5 and 4.0 dS m(-1)), and sources of complexed calcium (without calcium, complexed in organic acids, and complexed in amino acids). The following parameters were evaluated: height, stem diameter, root length, leaf area, dry mass (aerial part, root, and total), and Dickson's quality index. The results indicate that irrigation water with a salinity of 4.0 dS m(-1) negatively affects the growth and quality of sour passion fruit seedlings, reducing plant height by 72.44% in BRS GA1 and 58.76% in BRS SC1 in the treatment without calcium. Under saline conditions, calcium complexed in organic acids showed more consistent mitigating effects, increasing total dry mass by 43.77% compared to the treatment without calcium. The use of calcium complexed with organic acids represents a promising strategy to mitigate salt stress during the seedling stage of sour passion fruit.