Ultraviolet-B effects on stomatal density, water-use efficiency, and stable carbon isotope discrimination in four glasshouse-grown soybean () cultivars

Stable carbon isotope discrimination (Δ) showed both intraspecific and interspecific variations in leaves collected from field plants representing a wide range of peanut germplasm grown in similar environments. It was predicted, on the basis of theoretical models relating Δ and water-use efficiency (W), that there could be as much as 60% variation in W. The Δ of leaf material was used as a guide to select peanut genotypes for testing, in the glasshouse, for a correlation between Δ and W. Pot plants of nine peanut genotypes were grown in conditions of unlimited water availability or very restricted water supply. Water-use efficiency and Δ of leaves was measured on all plants. A strong correlation (r = -0.81) was found between Δ and W. Water-use efficiency actually varied as much as twofold. Carbon content and Δ were measured in all parts of some plants. The Δ values of all parts were highly correlated with and therefore well-represented by the Δ of the leaves. Calculation of W on a molar basis removes variation associated with carbon content of dry matter. On this basis, W was correlated with the discrimination against 13C of the whole plant. The link between Δ and W is not direct but the strong correlation between Δ and W suggests that other factors, which are discussed, do not interfere greatly. The data provide more evidence that Δ might be used as a selection technique for W in C3 species.

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Seedling growth, leaf water status and signature of stable carbon isotopes in C3 perennials exposed to natural phytochemicals

Australian Journal of Botany ◽

10.1071/bt12072 ◽

2012 ◽

Vol 60 (8) ◽

pp. 676 ◽

Cited By ~ 15

Author(s):

M. Iftikhar Hussain ◽

Manuel J. Reigosa

Keyword(s):

Water Use Efficiency ◽

Carbon Isotope ◽

Carbon Isotopes ◽

Water Use ◽

Stable Carbon Isotopes ◽

Carbon Isotope Discrimination ◽

Water Status ◽

Perennial Species ◽

Stable Carbon ◽

Use Efficiency

In the present study, we evaluated the seedling growth, water status and signature of stable carbon isotopes in C3 perennial species exposed to natural phytochemicals. Three perennial species, cocksfoot (Dactylis glomerata), perennial ryegrass (Lolium perenne) and common sorrel (Rumex acetosa), were grown for 30 days in perlite, watered with Hoagland solution and exposed to the phytochemicals benzoxazolin-2(3H)-one (BOA) and cinnamic acid (CA) at 0, 0.1, 0.5, 1.0 and 1.5 mM concentrations. BOA markedly decreased the leaf and root fresh weights of D. glomerata and L. perenne in a concentration-dependent manner. The leaf fresh weight (LFW) of plants treated with CA (1.5 mM) was similarly affected by showing a decrease of LFW, being the lowest in L. perenne (56%) followed by D. glomerata (46%). The relative water contents of L. perenne, D. glomerata and R. acetosa were decreased while maximum RWC reduction was observed in L. perenne. Carbon isotope discrimination in L. perenne, D. glomerata and R. acetosa were reduced following treatment with BOA and CA at 1.5 mM. BOA at 1.5 mM decreased the ratio of intercellular to ambient CO2 concentration relative to control in L. perenne, D. glomerata and R. acetosa. There was an increase in water-use efficiency in L. perenne, D. glomerata and R. acetosa after treatment with BOA and CA. The dry weight of plants treated with CA (1.5 mM) showed different patterns of variation, being lowest in L. perenne (33%) followed by D. glomerata (3%) and R. acetosa (2%). Phytotoxicity was higher for the perennial grass than for the perennial broadleaf. These results clearly demonstrate a widespread occurrence of phytotoxicity among the three species, their tolerance and relationship between carbon isotope discrimination and intrinsic water-use efficiency.

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