Growth and physiological responses of young plants of Dendrocalamus asper (Poaceae: Bambusoideae) under water stress / Crescimento e respostas fisiológicas de plantas jovens de Dendrocalamus asper (Poaceae: Bambusoideae) submetidas a estresse hídrico

Abstract

Understanding how water stress impacts the growth and physiology of young bamboo plants is important to define management strategies and successful field establishment of the species. In this study, young plants of Dendrocalamus asper were evaluated to determine the effects of water availability in the initial phase of growth and the physiological behavior of the species under these conditions. Four water deficit conditions (0%, 25%, 50% and 100% of field capacity) were applied in a completely randomized design. The plants were grown in pots under a tunnel-type greenhouse environment. At 7 and 30 days of imposition of treatments, growth characteristics and gas exchange were evaluated, and at 30 days, Chl a fluorescence, pigment concentration and dry mass were analyzed. Water stress affected the growth and gas exchange of young D. asper plants. Under lower water availability (25%), the plants had a significant reduction in the dry mass of leaves and stems at 30 days and, interestingly, a greater number of shoots was observed. Although photosynthetic efficiency did not differ statistically, D. asper plants have reduced stomatal conductance (gs) and transpiration (E) under higher water restriction (50% and 25%), and higher PN (net photosynthesis) under 50% of the field capacity. The behavior observed in young plants of D. asper shows tolerance to the level and period of imposed water stress. In addition, shoot emission seems to be the main survival strategy when cultivated under 25% of water availability. This study provides an initial analysis of the impact of water deficit on clonal plantlets of Dendrocalamus asper, and further research is needed to identify the physiological and biochemical mechanisms of this species under greater stress period.