| 个人简介 | |
|---|---|
 Dr. Iqbal Hussain Government College University, Faisalabad, Pakistan |
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| 标题： Silicon and abiotic stress in higher plants: progress and perspectives | |
| 摘要： Silicon (Si) is the second most abundant element after oxygen both on the earth’s surface and in soils, convincing evidence is still lacking that Si can meet the definition of essential elements for higher plants. Nevertheless, over the last hundred years, especially over the last three decades it has been well documented that Si is a beneficial or agronomically essential element for the healthy growth and development of many terrestrial plants. These beneficial effects are more distinct in plants exposed to various forms of abiotic (e.g. aluminium stress, heavy metals stress, salt stress, drought stress, high and low temperature stress, UV radiation stress, mineral-nutrient deficiency etc.) and biotic stress. This review focuses on overall updated knowledge of Si-mediated alleviation of abiotic stresses including metal stress, salt stress, drought and low-temperature stress and mineral nutrient deficiency etc. Yet, vast relevant research work has mainly focussed on the possible mechanisms by which abiotic stress is mitigated by Si at a physiological or biochemical level. For the metal tolerance, in general, there are two mechanisms, i.e. external mechanism and internal mechanism, proposed for explaining why and how Si can regulate plant resistance and/or tolerance to metal toxicity. Growing evidence suggests that Si is involved in regulating the expression of genes responsible for many plant metabolic processes, especially under heavy-metal-stress conditions. For the salt tolerance, it seems to suggest that (1) silica deposited on apoplast as SiO2 opal or phytolith can enhance water retention by inhibiting transpirational water loss, thus reducing salt-induced osmotic stress and (2) soluble Si in symplast may be actively involved in physiological and biochemical metabolisms by regulating the expression of genes related to the biosynthesis of hormones (ABA and JA etc.), antioxidant defense enzymes, H+ -pumps and osmolytes to rebalance ion stoichiometry, reduce membrane permeability and improve membrane structure and stability, hence improving salt tolerance in plants. The mechanisms for Si-mediated tolerance to drought and low-temperature stresses include promoting photosynthetic enzymatic activities, photochemical efficiency and photosynthetic rate, maintaining nutrient balance, improving water retention by decreasing water loss from leaves and increasing water uptake by roots, and scavenging reactive oxygen species by improving the capabilities of antioxidant defence. Compared with rapid and great progress made in dissecting the molecular mechanisms of Si uptake and transport, less work has been done on Si-mediated tolerance to varying forms of abiotic stress at a molecular level. To better understand the mechanisms underpinning Si-mediated resistance to abiotic stress, future work should focus on mechanistic investigations of Si and abiotic interactions at the molecular level with an emphasis on transcriptomic or proteomic studies. Key words: Abiotic stress; Antioxidant defense; Metal stress; Salt stress; Silicon | |
| 简介： Dr. Iqbal Hussain was born on February 10, 1973 at District Layyah (Punjab) Pakistan. He has been working as Tenured Associate Professor in the Department of Botany, Government College University, Faisalabad-38000, Pakistan Since 17-12-2017 to date. Research Interest: Plant Stress Physiology and Molecular Biology, Identification of Physio-biochemical Markers of stress tolerance. Education: PhD (2004-2009): Botany (Plant Stress Physiology and Molecular Biology), University of Agriculture, Faisalabad, Pakistan. Post-Doc (2016-2017): Foreign Fellowship Program of PHEC awarded for one year from Punjab Higher Education Commission (PHEC), under the supervision of Prof. Dr. Atsushi Higashitani Tadashi (Dean), Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan. | |
