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Photosynthesis and water‐relation traits of the summer annual C 4 grasses, Eleusine indica and Digitaria adscendens , with contrasting trampling tolerance
Author(s) -
Kobayashi Tsuyoshi,
Hori Yoshimichi
Publication year - 2000
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1046/j.1440-1703.2000.00335.x
Subject(s) - eleusine indica , transpiration , digitaria , trampling , biology , stomatal conductance , agronomy , botany , photosynthesis , water content , turgor pressure , water potential , horticulture , soil water , ecology , weed , geotechnical engineering , grazing , engineering
Two summer annual C 4 grasses with different trampling susceptibilities were grown as potted plants, and diurnal leaf gas exchange and leaf water potential in each grass were compared. The maximum net photosynthetic rate, leaf conductance and transpiration rate were higher in the trampling‐tolerant Eleusine indica (L.) Gaertn. than in trampling sensitive Digitaria adscendens (H. B. K.) Henr. Leaf water potential was much lower in E. indica than in D. adscendens . There were no differences in soil‐to‐leaf hydraulic conductance and leaf osmotic potential at full turgor as obtained by pressure–volume analysis. However, the bulk modulus of elasticity in cell walls was higher in E. indica leaves than in D. adscendens leaves. This shows that the leaves of E. indica are less elastic. Therefore, the rigid cell walls of E. indica leaves reduced leaf water potential rapidly by decreasing the leaf water content, supporting a high transpiration rate with high leaf conductance. In trampled habitats, such lowering of leaf water potential in E. indica might play a role in water absorption from the compacted soil. In contrast, the ability of D. adscendens to colonize dry habitats such as coastal sand dunes appears to be due to its lower transpiration rate and its higher leaf water potential which is not strongly affected by decreasing leaf water content.