Seed Osmopriming Improves Germination, Physiological, and Root Anatomical Attributes of Red Amaranth (Amaranthus tricolor L.) in Salinity Stress Condition

Salinity stress is a form of abiotic stress that threatens the sustainability of agriculture in almost all countries in the world. It has an impact in reducing plant productivity. Red amaranth (Amaranthus tricolor L.) is a vegetable crop that has high nutritional value, but extensive saline land area can cause red amaranth yields to decline. Osmopriming is a seed priming method in which seeds are immersed in a solution that has a high osmotic potential, such as PEG (polyethylene glycol) in order to increase germination under unfavorable conditions. This study determined the effect of osmopriming on germination, physiological, and root anatomical attributes of red amaranth roots under salinity stress conditions. The research design used a completely randomized design with two types of treatment, namely, osmopriming and salinity stress. Each treatment used three concentrations, seed osmopriming with 0%, 5%, and 10% of PEG and salinity stress of 0 mM, 50 mM, and 100 mM of NaCl. The measured parameters were germination, growth, physiological, and root anatomical characters. Osmopriming of seeds with 10% PEG increased germination as indicated by the germination percentage, time, and rate reaching 95.55%, 1.393 day, and 71.98%/day, respectively. Red amaranth plants that had been osmoprimed with 10% PEG grew faster when exposed to salinity stress. Application of PEG 5% and 10% increased total chlorophyll levels while decreasing proline levels and Ca-oxalate crystal density. Under salinity stress conditions, PEG application improved the root anatomical characters of red amaranth as shown by increased epidermis thickness, cortex thickness, and stele diameter. Priming application with 10% PEG has the potential to increase the tolerance of red amaranth to salinity stress.