Growth, Physiological, and Photosynthetic Responses of Xanthoceras sorbifolium Bunge Seedlings Under Various Degrees of Salinity

Abstract

Xanthoceras sorbifolium Bunge is priced for its medical and energetic values. The species also plays a key role in stabilizing ecologically fragile areas exposed to excess soil salinity. In this study, the effects of salinity on the growth, physiological, and photosynthetic parameters of X. sorbifolium Bunge were investigated. The X. sorbifolium seedlings were subjected to five salt treatments: 0 (control, CK), 70, 140, 210, and 280 mM of sodium chloride (NaCl) solutions. NaCl caused a decrease in plant height, specific leaf area, biomass, and root parameters. Leaf wilting and shedding and changes in root morphology, such as root length, root surface area, and root tips were observed. This study found that X. sorbifolium is tolerant to high salinity. Compared with the CK group, even if the concentration of NaCl was higher than 210 mM, the increase of the relative conductivity was also slow, while intercellular CO2 concentration had a similar trend. Moreover, NaCl stress caused an increase in the malondialdehyde (MDA), soluble proteins, and proline. Among the enzymes in the plant, the catalase (CAT) activity increases first and decreased with the increase in the intensity of NaCl stress, but the salt treatment had no significant effect on superoxide dismutase (SOD) activity. The peroxidase (POD) showed an increasing trend under salt stress. It was found that the photosynthesis of X. sorbifolium was notably impacted by saline stress. NaCl toxicity induced a noticeable influence on leaf net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (E), and water use efficiency (Wue). As salt concentration increased, the content of chlorophyll decreased. It can be found that a low concentration of NaCl induced the increase of photosynthetic capacity but a high-intensity exposure to stress resulted in the reduction of photosynthetic efficiency and SOD activity, which had a positive correlation. In summary, salt-induced ionic stress primarily controlled root morphology, osmotic adjustment, and enzyme activities of salt-treated X. sorbifolium leaves, whereas the low salt load could, in fact, promote the growth of roots.

Salt Stress Induces Changes in Physiological Characteristics, Bioactive Constituents, and Antioxidants in Kenaf (Hibiscus cannabinus L.)

“…Under salt stress, the proline content increased significantly in the current study. The present findings are consistent with previous research on Brassica species [ 44 ], Phaseolus vulgaris [ 72 ], and Xanthoceras sorbifoliu [ 65 ], which revealed an increase in proline content under salt stress. The enhancement of the proline content might be due to increased activity of the pyrroline-5-carboxylate synthase (P5CS) of the proline biosynthetic pathway in Hibiscus cannabinus under salt stress.…”

“…Soil salinization is now a major environmental threat to the long-term growth of global agriculture. It induces alterations in many physiological and metabolic processes, eventually reducing the crop yield, depending on the severity and duration of the stress [ 64 , 65 ]. Plants can tolerate or avoid saline conditions [ 65 ].…”

“…It induces alterations in many physiological and metabolic processes, eventually reducing the crop yield, depending on the severity and duration of the stress [ 64 , 65 ]. Plants can tolerate or avoid saline conditions [ 65 ]. This study examined the growth parameters, physiology characteristics, bioactive constituents, and antioxidant capacity of H. cannabinus to assess its ability to deal with salinity.…”

Phenotypic trait differences betweenIris pseudacorusin native and introduced ranges support greater capacity of invasive populations to withstand sea level rise

“…Thus, native I. pseudacorus plants tended to show lower SLA, but higher leaf N concentrations than alien plants in the introduced range, and higher numbers of senescent leaves per sprout with increasing salinity. Previous studies have recorded an increase in salt tolerance related to ion accumulation in senescent leaf tissue (Reddy et al, 2017) and increased SLA (Grewell et al, 2021; Zong et al, 2021). In contrast, alien plants, exposed to similar soil salinities as the native plants, also had decreased LWC and LER with increasing salinity gradient, but responded with about half the decrease in these leaf traits than observed for native plants.…”

Arbuscular mycorrhizal fungi alleviates salt stress in Xanthoceras sorbifolium through improved osmotic tolerance, antioxidant activity, and photosynthesis

“…Apart from the ecological functions and excellent resistant ability, X. sorbifolium also has valuable seeds, from which the oil extracted can be used to produce high-quality healthcare products, since the component in the oil is potentially effective for the treatment of Alzheimer’s disease, rheumatism, gout, and learning and memory impairment ( Ji et al, 2017 ; Wu et al, 2018 ; Li et al, 2020 ). In our previous study, it was found that X. sorbifolium Bunge could cope with the salt stress by osmotic, enzyme, and photosynthesis regulations, which could effectively alleviate the damage caused by saline treatment ( Zong et al, 2021 ). Wang et al also investigated the physiological changes and molecular mechanisms underlying the responses of X. sorbifolium to salt and saline-alkali stress ( Wang et al, 2020 ).…”