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Grasses of different C 4 subtypes reveal leaf traits related to drought tolerance in their natural habitats: Changes in structure, water potential, and amino acid content
Author(s) -
CarmoSilva Ana E.,
Francisco Ana,
Powers Stephen J.,
Keys Alfred J.,
Ascensão Lia,
Parry Martin A. J.,
Arrabaça Maria Celeste
Publication year - 2009
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.0800224
Subject(s) - cynodon dactylon , biology , japonica , botany , proline , water content , agronomy , cryptomeria , hordeum , zoysia japonica , water potential , horticulture , poaceae , hordeum vulgare , soil water , amino acid , ecology , biochemistry , geotechnical engineering , engineering
Three grasses (Poaceae) of different C 4 subtypes, Paspalum dilatatum (NADP‐malic enzyme [ME]), Cynodon dactylon (NAD‐ME) and Zoysia japonica (phosphoenolpyruvate carboxykinase), occur in natural habitats that differ in annual rainfall. Their leaf characteristics were studied to identify traits related to drought tolerance. Plants were grown in pots, and water deficit was gradually induced by withholding water. Leaves of Z. japonica had the greatest and P. dilatatum the lowest relative dry matter content. Transverse sections of leaves that developed during the water deficit showed little change compared to control leaves, consistent with low phenotypic plasticity. Anatomical features distinguished the three species, with xeromorphic characteristics most strongly represented in Z. japonica . The leaf relative water content (RWC) decreased with the soil water content similarly for the three grasses. However, at 80% RWC, the leaf water potential was −3.1 MPa for Z. japonica and only −1.3 MPa for P. dilatatum and C. dactylon . Soluble amino acids, especially proline, increased as RWC decreased in leaves of C. dactylon and Z. japonica . Phenylalanine, valine, leucine, and isoleucine increased more in Z. japonica than in the other two species. The results provide evidence that C. dactylon and, especially, Z. japonica have evolved leaf traits better suited to arid habitats.