Differential germination responses of plump and shriveled seeds to environmental factors and storage conditions in Tamarix laxa Willd.

Abstract

Tamarix laxa Willd. is a vital shrub widely distributed in arid and semi-arid regions. It serves as an excellent species for sand-fixing afforestation in saline-alkali and sandy desert lands and has medicinal properties for wind-dispelling and detoxifying. This plant produces two types of seeds: plump and shriveled. However, the effect of seed plumpness on germination has not been extensively studied. In this research, we found that 42 % of the seeds in T. laxa were plump, and 58 % were shriveled. We then investigated how different temperatures, light conditions, salt concentrations, and storage methods affect the germination of these seeds. Shriveled seeds were significantly smaller and had a lower germination percentage compared to plump seeds. T. laxa seeds exhibited a broad adaptability to temperature. Plump seeds showed over 90 % germination at three different temperatures, whereas shriveled seeds had a 57 % germination percentage at 15/30 °C. Continuous darkness significantly reduced the germination percentage for both seed types. Although T. laxa seeds displayed some salt tolerance, high salt concentrations (0.6 mol/L NaCl) markedly decreased their germination percentage. Freshly mature seeds initially had a 99 % germination percentage. However, seeds stored at room temperature for 90 days nearly lost their viability. In contrast, seeds stored at −18 °C for 180 days maintained a germination percentage above 80 %. Low-temperature storage effectively delayed the short-term loss of seed vitality. This study offers comprehensive insights into T. laxa seed germination, providing valuable information for desert restoration efforts.