Biometria, tolerância a estresses abióticos e conservação de sementes de Neoglaziovia variegata (Arruda) Mez: estratégias para lidar com o clima em transformação

Abstract

Neoglaziovia variegata (Arruda) Mez is an endemic herbaceous plant of the Caatinga, of economic importance, in addition to presenting medicinal and ornamental potential. Evaluating the physiological quality of seeds, their storage capacity and their responses to stress conditions are important elements in the development of conservation projects for the species. Thus, the objective of this study was to characterize populations of N. variegata, evaluate the best method for storing seeds and identify the thermal and saline limits for their germination. Fruits and seeds were collected from three populations of N. variegata, performing biometrics and evaluation of the physiological quality of the seeds. Six storage conditions were tested (permeable/impermeable x laboratory/cold chamber/freezer/liquid nitrogen) for one year. The seeds were subjected to thermal stress conditions (15, 20, 25, 30, 35, 40 °C) and saline stress conditions (0, 2, 4, 8, 10, 12, 14 and 16 dS/m-1 ). The seeds showed interpopulation variability. The weight and electrical conductivity allowed greater efficiency in determining vigor. It is recommended to use a tetrazolium solution at a concentration of 0.75% for 24 h to assess viability. The seeds can be stored for up to 12 months in a cold chamber, at room temperature and in liquid nitrogen, regardless of the type of packaging. Germination occurs at temperatures between 14 ±1 °C and 41 ±1 °C, with the optimum temperature of 31.1 °C, and is not affected in the worst climate scenario. The species tolerates salinity up to 12 dS.m-1 and demonstrates significant resilience after thermal and saline stresses.