Effect of salinity and temperature on germination and seedling growth indices and ionic relations in castor(Ricinus communis L.)

To evaluate the effect of salinity and temperature on germination, seedling growth, and ionicrelations in Castor a factorial experiment in a completely randomized design with four replications was conducted. Treatments consisted of salinity (zero, 25, 50, 100, 200, and 400 mM NaCl) and four temperature levels were 15, 20, 25, and 30 degrees Celsius respectively. In this study, germination percentage, germination rate, average germination time, root and shoot length, root and shoot dry weight, root to shoot weight ratio, shoot and root sodium, shoot and root potassium and the ratio of sodium to potassium was measured. By the increasing salinity levels, all germination indices decreased but salinity increased Root to shoot ratio and Germination time. Results showed that 20 °c had the highest germination rate, root length, shoot length, root fresh weight, shoot fresh weight, shoot dry weight, root, shoot dry weight, plant height Compared with other treatments. In this study, with increasing salinity level, the amount of shoot sodium, root sodium, and the ratio of sodium to potassium was increased. Also, the amount of potassium in roots and shoots decreased simultaneously. The temperature of 20 ° C had the lowest shoot and root mean germination time allocated shoot to root ratio and mean germination times. With increasing levels of salinity, the sodium content of shoot, root sodium, and sodium to potassium ratio was increased. Also, amount of potassium in roots and shoots increased by Increasing salinity levels, With increasing temperature amount of potassium reduced and sodium was increased