Prof.  Iqbal  Hussain
Government College University, Faisalabad,  Pakistan

Title: Silicon in Plants: Crop protection and Climate Change mitigation

Abstract:

In the last decades, the concentration of atmospheric CO₂ and the average temperature have been increasing, and this trend is expected to become more severe in the near future. Additionally, environmental stresses including drought, salinity, UV-radiation, heavy metals, and toxic elements exposure represent a threat for ecosystems and agriculture. Climate and environmental changes negatively affect plant growth, biomass and yield production, and also enhance plant susceptibility to pests and diseases. Silicon (Si), as a beneficial element for plants, is involved in plant tolerance and/or resistance to various abiotic and biotic stresses. Traditionally, it is suggested that an accumulation of Si in the epidermal tissue of the plant is the main mechanism which provides defense against insect and fungal attacks. The chemical properties of monosilicic acid maintain plant protection against the effects of heavy metal contamination. However, phenomenons associated with Si fertilization, such as increased plant resistance to drought, frost and viral attacks, were not explained. New data obtained from greenhouse, laboratory and field experiments, as well as from literature sources, allowed a new hypothesis to be formed with regard to reinforcement of the plant's defense system by active Si. The role of Si in the plant defense system will be presented, and the participation of Si in stress tolerance promotion in organisms will be discussed. According to the hypothesis, plants, as well as every other living organism (humans, animals and microorganisms) have unique protective mechanisms which involve in part the mobile Si compounds (mostly monosilicic acid and polysilicic acids). It is speculated that the function of the Si constituent can provide additional synthesis of stress protection molecules, and this synthesis is carried out under genetic control but without “physical” participation of the genetic apparatus. The assumption is based on indirect experiments, and on a basis of subordination of two constituencies: (a) response of genetic apparatus to stress, ensuring synthesis of stress protection compounds such as antioxidant enzymes, stress proteins, glutathione, phenols and others antioxidants, and (b) on additional non-enzymatic formation of the same protection compounds on the matrixes of polysilicic acids. The active forms of Si within plants are being considered as a matrix-depot for the formation of compounds which assist the organism(s) to maintain positive homeostasis under stressful conditions. This hypothesis provides the possibility of elaborating new ways to protect cultivated plants against unfavourable conditions and biotic stresses.

Keywords: plants, silicon, active silicon, stress tolerance

Sumaira Thind, Iqbal Hussain*, Shafaqat Ali, Rizwan Rasheed and Muhammad Arslan Ashraf (2021). Silicon application modulates growth, physio-chemicals and antioxidants in wheat (Triticum aestivum L.) exposed to different cadmium regimes. Dose-Response, 19 (2):1-15.

Sumaira Thind, Iqbal Hussain, Shafaqat Ali, Saddam Hussain, Rizwan Rasheed, Basharat Ali, Hafiz Athar Hussain (2020). Physiological and biochemical bases of foliar silicon-induced alleviation of cadmium toxicity in wheat. Journal of Soil Science and Plant Nutrition, 20(4), 2714-2730.

Iqbal Hussain, Abida Parveen, Rizwan Rasheed, Muhammad Arslan Ashraf, Muhammad Ibrahim, Saima Riaz, Zarbhakhat Afzaal, and Muhammad Iqbal (2019). Exogenous silicon modulates growth, physio-chemicals and antioxidants in barley (Hordeum vulgare L.) exposed to different temperature regimes. Silicon, 11, 2753–2762.

Iqbal Hussain, Muhammad Arslan Ashraf, Rizwan Rasheed, Anum Asghar, Muhammad Asim Sajid, Muhammad Iqbal. (2015). Exogenous application of silicon at the boot stage decreases accumulation of cadmium in wheat grains. Brazilian Journal of Botany, 38(2), 223-234.

Biography:

Research Interest:    Plant Stress Physiology, Plant Molecular Biology, Identification of Physio-biochemical Markers of stress tolerance, Thermal adaptation of plants for studying molecular and genetic mechanisms, QTLs study and Photochemistry

  Education:

PhD (2004-2009): Botany (Plant Stress Physiology and Molecular Biology), University of Agriculture, Faisalabad (a part of thesis research was completed under International Research Support Initiative Program (IRSIP) of HEC, Pakistan, under the supervision of Dr. Tadashi Sato, Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.

Dissertation: “Seasonal variations in some physiological and molecular responses of   maize (Zea   mays   L.)  under glass house conditions”. Supervisor:  Prof. Dr.  Abdul Wahid, Dept. of Botany, University of Agriculture Faisalabad.

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.