Photosynthetic Acclimation and Growth Responses to Elevated CO2 Associate with Leaf Nitrogen and Phosphorus Concentrations in Mulberry (Morus multicaulis Perr.)
2021
Shi, Songmei | Xu, Xiao | Dong, Xingshui | Xu, Chenyang | Qiu, Yuling | He, Xinhua
Mulberry (Morus spp.) is a multipurpose tree that is worldwide planted because of its economic importance. This study was to investigate the likely consequences of anticipated future elevated CO₂ (eCO₂) on growth, physiology and nutrient uptake of nitrogen (N), phosphorus (P) and potassium (K) in two most widely cultivated mulberry (Morus multicaulis Perr.) varieties, QiangSang-1 and NongSang-14, in southwest China. A pot experiment was conducted in environmentally auto-controlled growth chambers under ambient CO₂ (ACO₂, 410/460 ppm, daytime/nighttime) and eCO₂ (710/760 ppm). eCO₂ significantly increased plant height, stem diameter, leaf numbers and biomass production, and decreased chlorophyll concentrations, net photosynthetic rate, stomatal conductance and transpiration rate of these two mulberry varieties. Under eCO₂ leaf N and P, and root N, P and K concentrations in both mulberry varieties decreased, while plant total P and K uptake in both varieties were enhanced, and an increased total N uptake in NongSang-4, but not in QiangSang-1. Nutrient dilution and transpiration rate were the main factors driving the reduction of leaf N and P, whereas changes in plant N and P demand had substantial impacts on photosynthetic inhibition. Our results can provide effective nutrient management strategies for a sustainable mulberry production under global atmosphere CO₂ rising scenarios.
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