Effect of salinity and alkalinity on germination and root growth in industrial hemp (Cannabis sativa L.)

Abstract

Salinity and alkalinity are important abiotic stress factors that restrict the plant’s availability of water, cause ionic stress, and contribute to the disruption of cellular homeostasis. Both stress factors negatively impact all stages of plant development, with an emphasis on germination, which is the most sensitive due to direct contact of the embryo with saline solution in the soil. Industrial hemp (Cannabis sativa L.) has a high tolerance to NaCl stress but knowledge of the effects of different salt types is limited. Seeds of two hemp genotypes (Santhica 70 i Futura 83) were exposed to salinity (NaCl i Na2SO4) and alkalinity (NaHCO3 i Na2CO3) stress for 4 days. The germination percentage and root growth under all treatments were reduced in both genotypes compared to the control. After 2nd day of growth, Na2SO4 had the strongest inhibitory effect on germination and germination salt tolerance index (STI_G2) in both genotypes while the most detrimental effect on root growth was observed under 4-day exposure to Na2CO3 treatment. The least negative effect of salt stress on germination and root growth was observed under NaCl treatment, suggesting that the salt response is tissue-dependent. Futura 83 showed a higher germination percentage, higher values of STI_G2 and STI_G4, and longer roots than Santhica 70 in both NaCl and NaHCO3 treatments. Our results suggest that tolerance to salinity and alkalinity depends on genotype properties.

Keywords

• salinity
• alkalinity
• industrial hemp
• rooth growth
• germination