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 15/30oC. Continuous darkness significantly reduced the germination percentage for both seed types. Although T. laxa seeds displayed some salt tolerance, high salt concentrations (0.6mol/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 oC 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.