caa a22 4500 477109659 CHVBK 20180405111605.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF02257570 doi (NATIONALLICENCE)springer-10.1007/BF02257570 Effect of soil drying on growth, biomass allocation and leaf gas exchange of two annual grass species [Elektronische Daten] [Tibor Kalapos, Riki van den Boogaard, Hans Lambers] Influence of short-term water stress on plant growth and leaf gas exchange was studied simultaneously in a growth chamber experiment using two annual grass species differing in photosynthetic pathway type, plant architecture and phenology:Triticum aestivum L. cv. Katya-A-1 (C3, a drought resistant wheat cultivar of erect growth) andTragus racemosus (L.) All. (C4, a prostrate weed of warm semiarid areas). At the leaf level, gas exchange rates declined with decreasing soil water potential for both species in such a way that instantaneous photosynthetic water use efficiency (PWUE, mmol CO2 assimilated per mol H2O transpired) increased. At adequate water supply, the C4 grass showed much lower stomatal conductance and higher PWUE than the C3 species, but this difference disappeared at severe water stress when leaf gas exchange rates were similarly reduced for both species. However, by using soil water more sparingly, the C4 species was able to assimilate under non-stressful conditions for a longer time than the C3 wheat did. At the whole-plant level, decreasing water availability substantially reduced the relative growth rate (RGR) ofT. aestivum, while biomass partitioning changed in favour of root growth, so that the plant could exploit the limiting water resource more efficiently. The change in partitioning preceded the overall reduction of RGR and it was associated with increased biomass allocation to roots and less to leaves, as well as with a decrease in specific leaf area. Water saving byT. racemosus sufficiently postponed water stress effects on plant growth occurring only as a moderate reduction in leaf area enlargement. For unstressed vegetative plants, relative growth rate of the C4 T. racemosus was only slightly higher than that of the C3 T. aestivum, though it was achieved at a much lower water cost. The lack of difference in RGR was probably due to growth conditions being relatively suboptimal for the C4 plant and also to a relatively large investment in stem tissues by the C4 T. racemosus. Only 10% of the plant biomass was allocated to roots in the C4 species while this was more than 30% for the C3 wheat cultivar. These results emphasize the importance of water saving and high WUE of C4 plants in maintaining growth under moderate water stress in comparison with C3 species. Kluwer Academic Publishers, 1996 C3 nationallicence C4 nationallicence relative growth rate nationallicence Tragus racemosus nationallicence Triticum aestivum nationallicence water stress nationallicence A : photosynthetic rate nationallicence Ela : water loss on leaf area basis nationallicence gs : stomatal conductance for water vapour nationallicence IWR : inflorescence weight ratio nationallicence LA : total leaf area nationallicence LAR : leaf area ratio nationallicence LWR : leaf weight ratio nationallicence NAR : net assimilation rate nationallicence pi/pa : ratio of intercellular and atmospheric CO2 partial pressure nationallicence PPFD : photosynthetic photon flux density nationallicence PWUE : photosynthetic water use efficiency (A/gs) nationallicence RGR : relative growth rate nationallicence RW : total root dry weight nationallicence RWR : root weight ratio nationallicence SLA : specific leaf area nationallicence SWR : stem weight ratio nationallicence WUEB : water use efficiency of biomass production nationallicence ψleaf : leaf water potential nationallicence ψsoil : soil water potential nationallicence Kalapos Tibor Department of Plant Taxonomy and Ecology, L. Eötvös University, Ludovika tér 2, H-1083, Budapest, Hungary aut van den Boogaard Riki Department of Plant Ecology and Evolutionary Biology Utrecht University, Sorbonnelaan 16, 3584 CA, Utrecht, The Netherlands aut Lambers Hans Department of Plant Ecology and Evolutionary Biology Utrecht University, Sorbonnelaan 16, 3584 CA, Utrecht, The Netherlands aut Plant and Soil Kluwer Academic Publishers 185/1(1996-03-01), 137-149 0032-079X 185:1<137 1996 185 11104 https://doi.org/10.1007/BF02257570 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02257570 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kalapos Tibor Department of Plant Taxonomy and Ecology, L. Eötvös University, Ludovika tér 2, H-1083, Budapest, Hungary aut NATIONALLICENCE 700 1- van den Boogaard Riki Department of Plant Ecology and Evolutionary Biology Utrecht University, Sorbonnelaan 16, 3584 CA, Utrecht, The Netherlands aut NATIONALLICENCE 700 1- Lambers Hans Department of Plant Ecology and Evolutionary Biology Utrecht University, Sorbonnelaan 16, 3584 CA, Utrecht, The Netherlands aut NATIONALLICENCE 773 0- Plant and Soil Kluwer Academic Publishers 185/1(1996-03-01), 137-149 0032-079X 185:1<137 1996 185 11104 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer