Perianth and abiotic factors regulate seed germination of Haloxylon stocksii—A cash crop candidate for degraded saline lands

Abstract

AbstractHaloxylon stocksii, a common succulent halophyte of saline flats in Pakistan and adjacent countries, is utilized as forage, washing soda, and medicines by the local people. In addition, its cultivation can also prevent land degradation by erosion and salinity. Given that information about its seed ecology is limited, this study aimed to unveil the germination requirements of H. stocksii seeds. Seed morpho‐physical features and effects of perianth persistence, salinity (0–500‐mM NaCl), photoperiod (12 hr light/12 hr dark and 24 hr dark), thermoperiod (10/20°C, 15/25°C, 20/30°C, and 25/35°C), and osmotic stress (0 to −4.29 MPa) on germination and recovery were studied. Presence of perianth caused reductions both in imbibition and germination compared to seeds with perianth removed. Seeds germinated optimally under moderate (20/30°C) than lower (10/20°C and 15/25°C) and higher (25/35°C) temperatures. Under 24 hr dark seed germination was ~20% lower than that in 12‐hr photoperiod at 20/30°C and in distilled water. NaCl increment decreased germination, and only ~20% seeds germinated in the highest NaCl concentration. Ungerminated seeds, when shifted from salt solution to distilled water, showed high recovery of germination. Polyethylene glycol treatment also reduced germination, which was comparable with NaCl treatments. However, polyethylene glycol‐treated seeds showed low recovery, unlike NaCl‐treated seeds. Our data unveil that seeds of H. stocksii germinate optimally upon removal of perianth, under moderate temperature, in absence of salinity and/or osmotic stresses. This study thus provides essential baseline information for mass‐scale cultivation and conservation of H. stocksii in degraded arid‐saline areas.