title: Differential responses in photosynthesis, growth and biomass yields in two mulberry genotypes grown under elevated CO2 atmosphere.
abstract: This study was aimed to examine the responses of two mulberry genotypes (Morus alba L.), which include a drought tolerant (DT) Selection-13 (S13) and a drought susceptible (DS) Kanva-2 (K2) grown under elevated atmospheric CO2 concentration ([CO2]) of 550 μmol mol(-1). Although both genotypes exhibited positive responses to elevated CO2, S13 showed higher light saturated photosynthetic rates (A') and apparent quantum efficiency (AQE), suggesting better Rubisco carboxylation. Increased water use efficiency (WUEi) in elevated CO2 grown S13 (ES13) was due to reduced stomatal conductance (gs) and transpiration (E). Elevated CO2 significantly increased chlorophyll a fluorescence characteristics including maximum quantum yield of primary photochemistry (FV/FM) and performance index (PI(ABS)) suggesting an improved photosystem-II efficiency in both genotypes compared to their respective controls. Even though ES13 showed superior photosynthetic performance, accumulation of soluble and insoluble sugars (starch) were significantly low compared to elevated CO2 grown K2 (EK2), demonstrating higher sink capacity in ES13, which in turn resulted in better biomass yields. We conclude that S13 could be a potential genotype for mulberry-based short rotation forestry (SRF) to mitigate increasing atmospheric [CO2] as well as for the production of carbon neutral renewable bio-energy.
authors: Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India.
authors: Kalva Madhana
authors: KM
authors: Sekhar
authors: Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India.
authors: Rachapudi Venkata
authors: RV
authors: Sreeharsha
authors: Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, India. Electronic address: arrsl@uohyd.ernet.in.
authors: Attipalli Ramachandra
authors: AR
authors: Reddy
mesh_terms: D001272:Atmosphere; D018533:Biomass; D002245:Carbon Dioxide; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D055864:Droughts; D005453:Fluorescence; D005838:Genotype; D031625:Morus / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D010788:Photosynthesis / Q000235:genetics*; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism
chemical_list: D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D002245:Carbon Dioxide; D000077194:Chlorophyll A
keywords: Biomass; Chlorophyll a fluorescence; Elevated CO(2); Leaf biochemistry; Leaf gas exchange; Mulberry genotypes