Photosynthetic response of Guadua angustifolia Kunth and Bambusa vulgaris Schrad. ex J.C. Wendl. to different light intensities

Abstract

Photosynthetic response studies at different light intensities facilitate understanding plant physiology, optimizing management and sustainable use of species. The purpose of the research was to evaluate the photosynthetic response of G. angustifolia and B. vulgaris at different light intensities. Photosynthetic assimilation measurements were performed using a portable iFL - LCpro-SD system. The compensation point (% U ) was determined by three A/Ci curves under three different light intensity levels. The evaluation of the photosynthetic response to increasing light intensity was from 25 to 1800 PPFD µmol m-²s-¹. G. angustifolia presented a % U of 73.9 µmol CO, m{ ²s{ ¹, indicating higher carbon capture efficiency at lower concentrations compared to B. vulgaris, which showed a % U of 88.1 µmol CO, m{ ²s{ ¹. Furthermore, G. angustifolia exhibited a lower diurnal respiration rate (Rd) (0.33 µmol CO, m{ ²s{ ¹), which optimizes its energy efficiency, while B. vulgaris presented a higher Rd (1.08 µmol CO, m{ ²s{ ¹), implying higher energy consumption under low light intensity conditions. G. angustifolia did not show photoinhibition, as its photosynthetic assimilation rate increased continuously with light. In contrast, B. vulgaris experienced photoinhibition starting at 700 µmol m{ ²s{ ¹ of PPFD. These findings show that G. angustifolia is better adapted to capture carbon under conditions of low CO, concentrations and high light intensities, while B. vulgaris seems to be better adapted to environments with higher CO, concentrations.