Divergence in Life History Traits between Two Populations of a Seed-Dimorphic Halophyte in Response to Soil Salinity

Abstract

Production of heteromorphic seeds is common in halophytes growing in arid environments with strong spatial and temporal heterogeneity. However, evidence for geographic variation (reflecting local adaptation) is almost nonexistent. Our primary aims were to compare the life history traits of two desert populations of this halophytic summer annual Suaeda corniculata subsp. mongolica and to investigate the phenotypic response of its plant and heteromorphic seeds to different levels of salt stress. Dimorphic seeds (F1) of the halophyte S. corniculata collected from two distant populations (F0) that differ in soil salinity were grown in a common environment under different levels of salinity to minimize the carryover effects from the field environment and tested for variation in plant (F1) and seed (F2) traits. Compared to F1 plants grown in low soil salinity, those grown in high salinity (>0.2 mol⋅L-1) were smaller and produced fewer seeds but had a higher reproductive allocation and a higher non-dormant brown seed: dormant black seed ratio. High salinity during plant growth decreased germination percentage of F2 black seeds but had no effect on F2 brown seeds. Between population differences in life history traits in the common environment corresponded with those in the natural populations. Phenotypic differences between the two populations were retained in F1 plants and in F2 seeds in the common environment, which suggests that the traits are genetically based. Our results indicate that soil salinity plays an ecologically important role in population regeneration of S. corniculata by influencing heteromorphic seed production in the natural habitat.

Effects of water stress and NaCl stress on different life cycle stages of the cold desert annual Lachnoloma lehmannii in China

“…In L. lehmannii, the number of surviving seedlings and their height and root length decreased significantly as NaCl concentration increased. This characteristic of L. lehmannii is similar to that of the desert species Suaeda corniculata (Yang at al., 2017). However, the root/shoot ratio increased with an increase in NaCl concentration ( Fig.…”

Reproductive Physiology of Halophytes: Current Standing

“…NaCl treatment did not specifically decrease the development of reproductive organs in these species, and the production losses caused by high salinity may result from a reduction in flower production and/or a decrease in the flower fertility (Khatun and Flowers, 1995). Interestingly, our recent study found that the halophyte S. salsa produces a greater weight of seeds under high salinity than without saline treatment (Figure 2B; Guo et al, 2018); the same phenomenon has been observed in Suaeda corniculata (Yang et al, 2017). Similarly, in the halophyte C. maritima , seed production is stimulated by 50 to 100 mM NaCl as compared to a no-salt control treatment (Debez et al, 2004).…”

“…These characteristics may help the species to ensure seedling establishment and population succession in variable saline environments. Finally, though the seeds of S. corniculata are collected from two distant population (F 0 ), the descendants (F 1 and F 2 ) still kept phenotypic differences regardless of whether grown in low or high salinity, indicating that the traits of dimorphic seeds are genetically determined and that soil salinity only plays an ecological role in influencing heteromorphic seed production (high salinity results in fewer seeds and more non-dormant brown seeds) (Yang et al, 2017). Recently, Xu et al (2017) used dimorphic seeds of S. salsa to perform differential expression analysis by transcriptome and identified a series of genes related to embryo development, fatty acid metabolism, osmoregulatory substances, and plant hormones that may regulate seed dormancy or germination.…”

Adaptation of the Euhalophyte Suaeda salsa to High-Salinity Conditions

“…However, halophytes such as S. salsa treated with high concentrations of NaCl produce greater numbers of seeds and higher seed yields than control plants (Guo et al 2018). Other halophytes, such as Cakile maritima and Suaeda corniculata, also exhibit increased seed yields under saline conditions (Debez et al 2004;Yang et al 2017). In S. salsa, the increased seed number and seed yield under saline conditions is primarily due to enhanced vegetative growth, increased flower number, and reduced flower abortion.…”