Effects of salinity on growth, physiological and anatomical traits of Passiflora species propagated from seeds and cuttings

Salinity of the soil and irrigation water is one of the main factors limiting the growth of plants. The objective of this study was to assess the biometric, physiological and anatomical responses of passion fruit species Passiflora spp. propagated from cuttings and seeds under various salinity conditions. A completely randomized factorial design was used, with three species (P. edulis Sims, P. gibertii N.E.Br. and P. cincinnata Mast.), five salt concentrations (0.3, 1.8, 3.3, 4.8, and 6.3 dS m−1) and two propagation methods (cuttings and seeds), with twelve repetitions each. There was a negative effect of rising levels of NaCl for the majority of biometric and physiological traits evaluated. The species propagated from seeds presented the most severe morphophysiological and anatomical alterations under salinity. P. edulis (the most commonly cultivated species) showed the greatest morphophysiological changes under salinity, inducing larger stem diameter, chlorophyll content index, total water consumption, root dry weight, shoot dry weight, total dry weight, root dry weight/shoot dry weight ratio, root length and volume and also more severe anatomical alterations, such as midrib cell disorganization, greater thickness of palisade parenchyma, lower intercellular volume in the spongy parenchyma and greater deposition of calcium oxalate in the leaves and roots. On the other hand, the wild species, P. cincinnata and P. gibertii, were more tolerant to salinity, with less severe biometric, physiological and anatomical changes.