Effect of Seed Coating and PEG-Induced Drought on the Germination Capacity of Five Clover Crops

Abstract

The effect of coating the seed of clover crops by water absorbing seed process (WASP) technology pelletization on its germination capacity was studied in conditions of diverse drought intensities simulated by different concentrations of polyethylenglycol (PEG) 8000 solution. Drought resistance was monitored in the seed of five fodder clover species: Anthyllis vulneraria L., Medicago lupulina L., Trifolium repens L., Melilotus albus Medik. and Onobrychis viciifolia Scop. In the seed of given plant species, germination capacity was determined along with the share of dead and hard seeds. Although the coating significantly (p < 0.05) affected the drought resistance of seeds, the germination capacity increased only in conditions of milder drought (simulation with PEG: 0.1–0.3 mol). With the increasing intensity of drought induced by higher PEG concentrations (0.4–0.7 mol) the number of germinable seeds demonstrably decreased and the number of dead seeds increased in the coated seed as compared with the uncoated seed. The coated seed can be appropriate for use in M. lupulina, M. albus and T. repens, while the uncoated seed can be used in A. vulneraria and O. viciifolia.

Water Stress Inhibits Germination While Maintaining Embryo Viability of Subtropical Wetland Seeds: A Functional Approach With Phylogenetic Contrasts

“…Drought stress caused the death of seeds of group III, thus being classified as stress-sensitive species. Different proportions of seed mortality due to drought stress provoked by osmotic solutions (using PEG6000) have been reported in germination studies in the literature ( Silva et al, 2001 ; Miranda et al, 2014 ; Kintl et al, 2021 ). For seeds of a tropical legume tree, Silva et al (2001) described a mean proportion of dead seeds in about 15–18%, probably due to interaction with a germination delay caused by low water potential.…”

“…Moreover, orthodox seeds show a low water potential that is unable to reactivate enzymes to recover germination, leading to embryo death ( Garwood and Lighton, 1990 ; Ebone et al, 2019 ). In cultivated clover species, the number of dead seeds increased both in the coated (pelleted) seeds and the uncoated ones ( Kintl et al, 2021 ). As expected, we found an enhanced proportion of dead seeds with lower water potentials, mostly in the light treatments.…”

Improved drought tolerance of EMS mutagenized Alfalfa (Medicago sativa L.) mutants by in vitro screening at germination stage

“…It is well known that PEG cannot pass through the cell wall due to its high molecular weight and are able to regulate water potential of embryonic cells via controlling poor water flow from xylem to the nearby cells and limits the process of cell growth mainly due to the loss of turgor 19 , resulting impaired cell elongation and inhibition of seed germination 20 . The germination variation in the simulated drought stress with PEG has also been reported for other important crops including alfalfa 21 , clover 16 and wheat 22 .…”

“…Therefore, new alfalfa cultivars which tolerate drought stress better at germination stage are needed to minimize and to ensure production stability of alfalfa. Previous reports indicated that osmotic substances with high molecular weight such as PEG are one of the most popular approaches for screening of target genotypes at germination or other development stages of many plants including alfalfa 16 . A positive correlation between germination on PEG supplemented media and the whole plant behavior under water deficit conditions in the field was also reported 17 .…”

Comparative Analysis of Tolerance to Salt Stress and Water Deficit in Two Invasive Weeds of the Genus Erigeron (Asteraceae)

“…The standard method to test the osmotic effect on germination is by using different concentrations of polyethylene glycol (PEG), which mimics environmental drought conditions [ 65 , 66 , 67 , 68 ]. Germination of the two species proved to be tolerant to osmotic stress, no significant differences were obtained with respect to the control up to the highest PEG concentration in E. bonariensis where 92% of the seeds and in E. sumatrensis 60% of the seeds germinated, a considerably lower reduction than under NaCl.…”