Accumulation of Silicon and Changes in Water Balance under Drought Stress in Brassica napus var. napus L.

Diana Saja-Garbarz,Franciszek Janowiak,Katarzyna Kaczanowska,Agnieszka Ostrowska

doi:10.3390/plants10020280

Abstract

The aim of this study was to investigate the accumulation of silicon in oilseed rape and to characterize the changes in chosen water balance parameters in response to drought. The following parameters were estimated: water content, osmotic and water potential, evapotranspiration, stomatal conductance and abscisic acid level under optimal and drought conditions. It was shown that oilseed rape plants accumulate silicon after its supplementation to the soil, both in the case of silicon alone and silicon together with iron. It was revealed that silicon (without iron) helps maintain constant water content under optimal conditions. While no silicon influence on osmotic regulation was observed, a transpiration decrease was detected under optimal conditions after silicon application. Under drought, a reduction in stomatal conductance was observed, but it was similar for all plants. The decrease in leaf water content under drought was accompanied by a significant increase in abscisic acid content in leaves of control plants and those treated with silicon together with iron. To sum up, under certain conditions, silicon is accumulated even in non-accumulator species, such as oilseed rape, and presumably improves water uptake under drought stress.

Highlights

Plant water economy is associated with the processes of uptake, transport, use and loss of water, and its balance depends on the impact of abiotic and biotic environmental factors
The analysis of total Si content in the above-ground part of plants growing under optimal conditions revealed that significantly higher Si content compared to control was found in the shoots supplemented with silicon, and the highest in those treated with silicon together with iron (Table 1)
The present study showed that the decrease in leaf water content under drought stress significantly increased abscisic acid (ABA) content in leaves of control plants and those treated with Si + Fe (Figure 4), which, combined with the reduction in their stomatal conductance relative to optimal growth conditions, contributed to maintaining osmotic balance under conditions of water shortage, and demonstrated the adjustment of plants to such stress conditions

Summary

Introduction

Plant water economy is associated with the processes of uptake, transport, use and loss of water, and its balance depends on the impact of abiotic and biotic environmental factors. The majority of environmental stress factors have a direct impact on the disturbance of water balance in the plant and stimulate a range of complex cellular and physiological responses which initiate the implementation of water-saving strategies [1]. Drought-related stress hinders plant production, and as arid and semi-arid regions already constitute over 30% of the world’s land surface, it is a serious threat to agriculture [2]. This effect is further exacerbated by climate change caused by human activity [3]. Plants subjected to drought undergo morphological as well as physiological and biochemical changes [4,5]

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