Plant, Soil and Environment - In Press
Selenium promotes soybean sprout growth via enhanced antioxidant capacity and nutrient mobilizationOriginal Paper
Kaiwei Li, Lele Li, Yuqing Liu, Sanchun Lei, Minghao Hao, Qiong Wu, Feiyan Yu, lianhe zhang
Selenium (Se) biofortification of soybean sprouts presents a promising approach for enhancing dietary Se intake. However, the physiological mechanisms of Se promoting growth remain poorly understood. Here, we investigated the effects of selenite (Na₂SeO₃) at concentrations of 0, 2.5, 5.0, 7.5, and 10 μmol/L on soybean sprout development over 72 hours. The results indicated that 5.0 and 7.5 μmol/L Na₂SeO₃ significantly promoted hypocotyl elongation and biomass accumulation. Se predominantly accumulated in the radicle, followed by the hypocotyl and cotyledon. Moderate selenite levels enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX); increased the concentrations of reduced glutathione (GSH), ascorbic acid (AsA), and free proline; and effectively suppressed the accumulation of superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂), thereby reducing malondialdehyde (MDA) concentration and alleviating oxidative stress. Concurrently, amylase and protease activities in cotyledons were stimulated, accelerating the hydrolysis of storage reserves. The resulting increases in soluble sugars, proteins, and free amino acids in the hypocotyl supported its elongation and biomass increase. In contrast, 10 μmol/L Na₂SeO₃ suppressed antioxidant enzyme activities, elevated reactive oxygen species (ROS) and MDA levels, and inhibited growth. Collectively, these findings demonstrate that moderate Se enhances soybean sprout growth primarily by enhancing the antioxidant capacity, reducing oxidative stress, and facilitating the mobilization of storage reserves toward the elongating hypocotyl, revealing key physiological mechanisms for cultivating high-quality, Se-enriched sprouts.
Physiological mechanisms mediated by selenite in alleviating PEG-induced drought stress during rice seed germinationOriginal Paper
ying Wang, qing Zhu, xue Luo, gaogao Dai, jingwen Hou, feiyan Yu, lianhe Zhang
Drought stress severely impresses seed germination, a critical stage determining crop seedling establishment. Selenium (Se) is a potential mitigator of abiotic stress, but its physiological mechanisms for alleviating osmotic stress during seed germination remain poorly understood. This study investigated how selenite alleviates rice seed germination inhibited by polyethylene glycol (PEG)-simulated drought. Results revealed that co-application of selenite (PEG+Se) significantly alleviated the PEG-induced suppression of germination. Selenite effectively bolstered the antioxidant defense system, increasing the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) and elevating the pools of glutathione (GSH) and ascorbate (AsA). Consequently, it attenuated the PEG-induced burst of reactive oxygen species (H₂O₂ and O₂⁻) and reduced lipid peroxidation (MDA concentration). Furthermore, selenite partially restored osmotic homeostasis by increasing the concentrations of of soluble sugar, soluble protein, free amino acids, and free proline. It also mitigated the inhibitory effect of PEG on the activities of α-amylase and protease, crucial enzymes for reserve mobilization during germination. Notably, while PEG stress significantly inhibited the uptake of exogenous Se in the germinating seeds, the beneficial effects of selenite were observed despite reduced Se accumulation. These results collectively demonstrate that selenite alleviates PEG-induced osmotic stress in germinating rice seeds by reinforcing the antioxidant system, maintaining osmotic balance, and sustaining reserve hydrolysis. This study provides novel insights into Se-mediated drought tolerance during germination and supports its potential application as a seed priming agent to improve crop seedling establishment under water-deficient conditions.
Molecular responses of Vetiver grass (Chrysopogon zizanioides) as phytoremediator to phenanthrene soil pollution stressOriginal Paper
Sasan Mohsenzadeh, Nadereh Naderi, Zahra Janbazi, Mehdi Zarei, Mahdi Nazari
Polycyclic Aromatic Hydrocarbons (PAHs) like phenanthrene are persistent environmental pollutants. This study evaluated the potential of Vetiver grass for the phytoremediation of phenanthrene-contaminated soil and investigated key detoxification mechanisms. Vetiver grass was exposed to various phenanthrene concentrations (0-4000 mg/kg), and its response was analyzed. The results demonstrated that Vetiver grass effectively removed phenanthrene from the soil, achieving a 68.9% reduction at the highest concentration (4000 ppm). This removal was accompanied by a significant upregulation of stress-related enzymes. Gene expression of Glutathione-S-Transferase (GST) increased in both roots and shoots, with the highest levels observed at 4000 ppm. Similarly, the expression of Phenylalanine Ammonia-Lyase (PAL) in roots was significantly enhanced at 250 and 4000 ppm. In conclusion, Vetiver grass shows high potential for phenanthrene phytoremediation. The enhanced expression of GST and PAL enzymes is a crucial molecular mechanism that mitigates phenanthrene toxicity and contributes to its successful removal from contaminated soil