Abstract
Physiological features associated with differential resistance to salinity were evaluated in two sugarcane (Saccharum spp. hybrid) cultivars over an 8-week period during which greenhouse-grown plants were drip-irrigated with water or with NaCI solutions of 2, 4, 8, or 12 decisiemens (dS) m-1 electrical conductivity (EC). The CO2 assimilation rate (A), stomatal conductance (g), and shoot growth rate (SGR) began to decline as EC of the irrigation solution increased above 2 dS m-1. A, g, and SGR of a salinity-resistant cultivar (H69-8235) were consistently higher than those of a salinity-susceptible cultivar (H65-7052) at all levels of salinity and declined less sharply with increasing salinity. Carbon isotope discrimination ([delta]) in tissue obtained from the uppermost fully expanded leaf increased with salinity and with time elapsed from the beginning of the experiment, but [delta] was consistently lower in the resistant than in the susceptible cultivar at all levels of salinity. Gas-exchange measurements suggested that variation in [delta] was attributable largely to variation in bundle sheath leakiness to CO2 ([phi]). Salinity-induced increases in [phi] appeared to be caused by a reduction in C3 pathway activity relative to C4 pathway activity rather than by physical changes in the permeability of the bundle sheath to CO2. A strong correlation between [delta] and A, g, and SGR permitted these to be predicted from [delta] regardless of the cultivar and salinity level. [delta] thus provided an integrated measure of several components of physiological performance and response.
Full Text
The Full Text of this article is available as a PDF (610.3 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bowman W. D., Hubick K. T., von Caemmerer S., Farquhar G. D. Short-term changes in leaf carbon isotope discrimination in salt- and water-stressed c(4) grasses. Plant Physiol. 1989 May;90(1):162–166. doi: 10.1104/pp.90.1.162. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hubick K. T., Hammer G. L., Farquhar G. D., Wade L. J., von Caemmerer S., Henderson S. A. Carbon isotope discrimination varies genetically in c(4) species. Plant Physiol. 1990 Feb;92(2):534–537. doi: 10.1104/pp.92.2.534. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martin B., Thorstenson Y. R. Stable Carbon Isotope Composition (deltaC), Water Use Efficiency, and Biomass Productivity of Lycopersicon esculentum, Lycopersicon pennellii, and the F(1) Hybrid. Plant Physiol. 1988 Sep;88(1):213–217. doi: 10.1104/pp.88.1.213. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vetterli MC, Jackson KP, Celler A, Engel J, Frekers D, Häusser O, Helmer R, Henderson R, Hicks KH, Jeppesen RG. The 70,72Ge(n,p)70,72Ga reactions: Suppression of Gamow-Teller strength near N=40. Phys Rev C Nucl Phys. 1992 Mar;45(3):997–1004. doi: 10.1103/physrevc.45.997. [DOI] [PubMed] [Google Scholar]