The aim of this study was to explore whether nutrition supply can improve the drought tolerance of Moso bamboo under dry conditions. One-year-old seedlings were exposed to two soil water content levels [wellwatered, 70 ± 5% soil-relative-water-content (SRWC) and drought stress, 30 ± 5% SRWC] and four combinations of nitrogen (N) and phosphorus (P) supply (low-N, low-P, LNLP; low-N, high-P, LNHP; high-N, high-P, HNHP; and high-N, low-P, HNLP) for four months. Plant growth, photosynthesis, chlorophyll fluorescence, water use efficiency and cell membrane stability were determined. The results showed that drought stress significantly decreased total biomass, net-photosynthesis (Pn), stomatal-conductance (gs), leaf-chlorophyll-content (Chlleaf), PSII-quantum-yield (ΦPSII), maximum-quantum-yield-of-photosynthesis (Fv/Fm), photochemical-quenching-coefficient (qP), leaf-instantaneous-water-use efficiency (WUEi), relative-water-content (RWC), photosynthetic-N-use-efficiency (PNUE), and photosynthetic-P-use-efficiency (PPUE). N and P application was found to be effective in enhancing the concentration of leaf N, gs, and Pn while reducing the production of reactive oxygen species under both water regimes. Under LNHP, HNHP and HNLP treatments, the decreases in total biomass, Pn, Chlleaf and Fv/Fm of drought-stressed were less evident than the decreases under LNLP. The study suggests that nutrient application has the potential to mitigate the drastic effects of water stress on Moso bamboo by improving photosynthetic rate, water-use efficiency, and increasing of membrane integrity.

Drought stress is a key environmental factor limiting the growth and productivity of plants. The purpose of this study was to investigate the physiological responses of Camptotheca acuminata (C. acuminata) to different drought stresses and compare the drought tolerance between the provenances Kunming (KM) and Nanchang (NC), which are naturally distributed in different rainfall zones with annual rainfalls of 1000–1100 mm and 1600–1700 mm, respectively. We determined relative water content (RWC), chlorophyll content [Chl(a+b)], net photosynthesis (Pn), gas exchange parameters, relative leakage conductivity (REC), malondialdehyde (MDA) content and superoxide dismutase (SOD) and peroxidase (POD) activities of C. acuminata seedlings under both moderate (50% of maximum field capacity) and severe drought stress (30% of maximum field capacity). As the degree of water stress increased, RWC, Chl(a+b) content, Pn, stomatal conductance (Gs), transpiration rate (Tr) and intercellular CO2 concentration (Ci) values decreased, but water use efficiency (WUE), REC, MDA content and SOD and POD activities increased in provenances KM and NC. Under moderate and severe drought stress, provenance KM had higher RWC, Chl(a+b), Pn, WUE, SOD, and POD and lower Gs, Tr, Ci, and REC in leaves than provenance NC. The results indicated that provenance KM may maintain stronger drought tolerance via improvements in water-retention capacity, antioxidant enzyme activity, and membrane integrity.