Effect of temperature, drought and salinity stresses on germination of ten medicinal plant seeds
Subject Areas :
Mehrab Yadegari
1
(
Associate Professor, Department of Agronomy and Medicinal Plants, Faculty of Agriculture, Islamic Azad University, Shahrekord Branch, Shahrekord, Iran
)
Abdollah Ghasemi
2
(
Department of Agronomy and Medicinal Plants, Faculty of Agriculture, Islamic Azad University, Shahrekord Branch, Shahrekord, Iran
)
Keywords: NaCl, Seed, Thyme, Lemon Balm, purslane, PEG,
Abstract :
To study the effects of salinity, temperature and drought stresses on germination indices in seeds of alyssum, dill, borage, marigold, saint john's wort, lemon balm, purslane, feverfew, thyme, and fenugreek, factorial experiments in laboratory conditions were performed in laboratory conditions in completely randomized design with 4 replication. The treatments contained of salinity at 4 NaCl concentrations (0, 0.25, 0.5, 0.75 mM), Drought (PEG in 0, -0.6, -0.9, -1.2 bar) and Temperature (10/20, 15/25, 20/30, 25/35 °C night/day). The results showed that the treatments had significant effect on germination indices. By comparisons between species, the greatest seed vigour and germination percentage were made in seeds of purslane, then purslane seeds were the most tolerant to drought and salinity and other hand, the seeds of lemon balm and thyme in most of measured characters had the minimum values. By increasing salinity and drought levels, root dry/fresh weight, stem dry/fresh weight, root/stem length and vigour of seeds were decreased in all species. Germination percentage was increased by higher level of temperature but decreased by upper levels of salinity and drought stresses. The highest seed vigour was made in temperature of 20/30°C night/day and no salinity and drought stress (control) and the least related to the temperature degrees of 10/20°C night/day and concentration of 0.75 mM of NaCl and -1.2 bar of PEG. Then the seed of plants for example purslane can introduce for planting in salinity and drought regions, and seed of plants such as thyme and lemon balm ought not to suggest for sowing in this regions.
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