Jurga Jankauskiene doctoral degree is in the Biomedical science area, research field of Biology. Thesis title is “Physiological-biochemical peculiarities of oilseed rape (Brassica napus L.) cold acclimation”. She work in the Laboratory of Plant Physiology at Institute of Botany, Nature Research Centre as a researcher. Also, she is a lecturer in the Department of Biology at Lithuanian University of Educational Sciences. Main research interests: plant physiology, plant biochemistry. She is currently engaged in research of protein composition, phytohormones (IAA and ethylene) and plant growth regulators importance in plant resistance to adverse environmental factors. She is a member of Plant physiological society (Lithuania), Biochemical society (Lithuania) and the Botanical Society of Japan (Japan).
Temperatures below the optimal for plant growth and development influence a reduction in growth rate, stem elongation, leaf expansion and stomata movements, and cause changes in principal physiological and biochemical processes and thus reflect the plant growth and productivity (Browse and Xin, 2001). Plants subjected to unfavorable temperatures undergo an increased exposure to the reactive oxygen species (ROS), and the accumulation of free radicals provokes damages in membranes and build up of lipids peroxides. As polyamines possess free radical scavenging features and antioxidant activity, they stabilize negatively charged macromolecules and may confer plant tolerance to unfavorable temperatures. It could be proposed, that exogenous application of some polyamines should eliminate the harmful effects of temperature and influence garden pea (Pea sativum L.) and kidney bean (Phaseolus vulgaris L.) productivity. The goal of research was to improve garden pea and kidney bean temperature tolerance and productivity via different concentrations of polyamines applications to plants with different low temperature tolerance under controlled and natural growth conditions. We used polyamines – spermine, spermidine and putrescine at concentrations of 0.1 and 1.0 mM as plant physiological and biochemical processes modifiers. The hydrogen peroxide (H2O2) and malondialdehyde (MDA) were investigated as stress markers. Plant yield structural elements (silique number on plants, seed number per silique and 1000 seed weight) were assessed in the stage BBCH 89. Under controlled growth conditions MDA and H2O2 content in low temperature treated plants was increased. Application of polyamines caused a slight additional increase of MDA content, this effect in garden pea (more tolerant to low temperature) was more significant.
Under low temperature conditions H2O2 content in polyamines treated plants was higher. Among ROS species, H2O2 is an important signaling molecule which is produced by the chloroplast and involved in the response of the plant to different types of environmental stressors (Belkadhi et al., 2014; Jajic et al., 2015). Many researchers discuss about actual concentration of H2O2 in tissues – which one is optimal for plants to maintain homeostasis and which one is harmful (Belkadhi et al., 2014; Jajic et al., 2015). We supposed that higher content of H2O2 after polyamines applications in kidney bean played as signaling molecule to switch defense system in this plant.
Analysis of plant yield structural elements showed that polyamines noticeably enhanced the pea and kidney bean productivity elements.