Extracellular polysaccharide and leaf capacitance in a Hawai`ian bog species, Argyroxiphium grayanum (Compositae-Madiinae)
Robichaux RH and Morse SR. 1990. Extracellular polysaccharide and leaf capacitance in a Hawai`ian bog species, Argyroxiphium grayanum (Compositae-Madiinae). American Journal of Botany. 77(1):134-138
Mathure leaves of A.grayanum exhibit and unusual structure-function relationship. The leaves are traversed by several large channels filled with extracellular polysaccaride. Infared spectral data suggeests that the polysaccharide is mainly pectin, which is consistent with previous data based its histochemical staning properties. The polysaccharide exhibits a very high water-holding capacit, which appears to result in a very high leaf capacitance at a high watercontents and water potentials. The volume normalized leaf capacity of A. grayanum is .67 MPa-1 over the water potential range of -0.1 to -0.5 MPa. Coupled with the low time constant for water flux within the leaves (57 sec), The high leaf capacitance of A. grayanum may enable it to avoind rapid declines in leaf water potential. Thus inits negative bog habitat in Hawaii the high leaf capacitance of A grayanum may be of benefit in terms if minimizing the development of short term leaf water deficits.
- Type
- Journal Article
- Authors
- Robichaux, Robert; Morse, Suzanne
- Units
- HALE
- Keywords
- Foliage, greensword (Argyroxiphium grayanum), Hawai`i, Plant Studies, polysaccharide, silversword alliance (Compositae: Madiinae)