Morphophysiology of yellow passion-fruit seedlings cultivated with macrophyte (Eichhornia Crassipes) under salt stress

The use of aquatic macrophyte biomass could be a viable alternative for producing substrates. The objective was to evaluate the production of yellow passion fruit seedlings in different macrophyte-based substrates under salinity stress. The experiment was carried out at the Seedling Production Unit in Redenção, Ceará state. A completely randomized design was used, in a 2 × 5 factorial arrangement, with respect to two electrical conductivities of irrigation water (0.8 and 2.5 dS m-1) and five substrates (S1 = 54% soil + 29. 5% sand + 16% macrophyte; S2 = 34% soil + 33% sand + 33% macrophyte; S3 = 24% soil + 26.5% sand + 49.5% macrophyte; S4 = 20% soil + 14% sand + 66% macrophyte; and S5 = 10% soil + 7.5% sand + 85.5% macrophyte), with 10 replications. Salt stress negatively affected photosynthesis, transpiration, stomatal conductance and internal CO2 concentration of yellow passion-fruit seedlings. The use of S1 (54% soil + 29.5% sand + 16.5% macrophyte) was more efficient for plant height, leaf area, shoot dry mass, root dry mass, and total dry mass, while S5 (10% soil + 7.5% sand + 82.5% macrophyte) provided higher photosynthesis in yellow passion fruit seedlings. Substrate 1 (54% soil + 29.5% sand + 16.5% macrophyte) and S3 (24% soil + 26.5% sand + 49.5% macrophyte) alleviated salinity stress on Dickson quality index and stem diameter. The use of macrophytes has been shown to be beneficial in the production of passion fruit seedlings, with positive effects on development and gas exchange, and alleviation of salt stress. Keywords: aquatic plant, Passiflora edulis, salinity, substrate.