Investigation on Germination and seedling growth of three Salicornia species in response to different levels of salinity stress originated from sodium chloride using Gompertz function

Salicornia is one of the most important industrial plants of the Chenopodiaceae family, which is grown as oilseed, fodder, or vegetable crop around the world. All Salicornia species produce succulent shoots suitable for leafy vegetable production, but they differ in germination charactristics, seedling growth and physiological parameters. Germination and seedling emergence depend on the specific genotype requirements of each species and the environmental factors such as salinity stress. Salinity stress is one of the major abiotic stresses which negatively limit crop productivity. The aim of the present study was to test biochemical and physiological responses of Salicornia species to salinity stress.

In order to investigate the seed germination and seedling growth properties of Salicornia, two separate factorial experiments were conducted based on a completely randomized design with four replications and four destructive examples for each replication during 2019. The first experiment (seed investigation) was carried on in the petri dish culture and second experiment (seedling investigation) was conducted using pots in the green house condition. Experimental treatments were six levels of salinity stresses (control, 10, 20, 30, 40 and 50 dS/m) arranged as the fist factor and in the second factor was three Salicornia species S. persica Golestan, S. biglovii and S. europaea.

Results of analysis of variance revealed that there was significant effect of salinity stress, genotype and interaction effects of both treatment on all measured germination and seedling growth characteristics (p<0.01). In all studied Salicornia species, the maximum value of traits obtain at control condition and the minimum value was observed in 50 dS/m salinity except for germination uniformity, seedling water content and total phenol content. The highest seedling water content (89.44%) was obtained from S. persica at 40 dS/m. The maximum flavonoid (0.156 mg/g.fw) and total phenol content (0.031 mg/g.fw) was observed in S. persica at 20 dS/m. Based on the output of Gompertz function (R2adj≥0.95 and RMSE≤3.25), salinity increase from 0 to 50 dS/m, the time to reach 50% of total seed germination was increased from 5.73 to 16.20 days in S. percia, 4.42 to 17.07 days in S.biglovii and 5.75 to 11.95 days, respectively.

Seed germination traits and seedling growth of Salicornia genotypes exhibited some level of sensitivity to salinity stress. All Salicornia species were germinated successfully at a salinity of 10 dS/m while seed germination was inhibited at 50 dS/m of salinity stress. It was revealed that the Salicornia sp. originated from Iran (S. persica) exhibited higher salinity tolerance than the species originated from Europe (i.e., S. biglovii and S. europaea). In conclusion, all Salicornia spp. exhibited reasonable salinity tolerance in the range of (10 to 30 dS/m) without compromising the high quality of the final yield. Therefore, it could be a promising alternative crop in saline-prone areas of Iran. Now, after understanding the behavior of different Salicoenia species above 10 dS/m salinity and increae of seed germination from 0 to 10 dS/m in, scrutiny of plants reaction between 0 to 10 dS/m in, it is possible to use this finding for a better breeding program of Salicornia species.