APPARENT PHOTOSYNTHESIS AND LEAF CHARACTERS IN RELATION TO LEAF POSITION AND AGE, AMONG CONTRASTING LOLIUM GENOTYPES

Abstract

SUMMARYThe effect of leaf position, specific leaf weight and chlorophyll on light-saturated apparent photosynthesis, and their relationships with leaf mesophyll, among contrasting Lolium genotypes are described. Within a range of up to four fully expanded leaves on a tiller, the lower (older) leaves had greater photosynthetic activity than the upper (younger). For any particular leaf, maximum photosynthesis was attained prior to full expansion. These effects were closely related to differences in mesophyll cell size. A wide range in leaf chlorophyll levels exhibited by Lolium mutants was not associated with differences in apparent photosynthesis. Specific leaf weight and chlorophyll content were greater in thin leaves with small mesophyll cells than in thick leaves with large cells. Chlorophyll content was not associated with differences in photosynthesis in limiting light (500 ft-candles).

Proportional dry‐mass content as an underlying trait for the variation in relative growth rate among 22 Eurasian populations of Dactylis glomerata s.l.

“…This has been found for grasses (Wilson & Cooper 1969;Garnier & Laurent 1994;Ryser & Lambers 1995;Van Arendonk et al 1997), dicot herbs (Dijkstra 1989;Meerts & Garnier 1996) and trees (Lei & Lechowicz 1990, Kloeppel & Abrams 1995. Among 34 angiosperm species, tissue dry-mass content explained interspecific variation in SLA better than leaf thickness (Shipley 1995).…”

Leaf anatomy, specific mass and water content in congeneric annual and perennial grass species

“…Therefore, the mfluence of an)-of these traits taken separately on LSM will depend on its combination with tbe otber two. This !s probably why no consistent effect of cell size on LSM bas been found: Wilson & Cooper (1969) and Dijkstra & Lambers (]989fl) found tbat low LSM coincided with large cells in different genotypes of Lolium. perenne and Plantago mafor, respectively, while Pammenter et al (1986) found tbat species with tbe bigber LSM also had larger cells.…”

“…Leaf density bas seldom been measured, but sparse data suggest that leaves with a bigb LSM tend to bave a bigh proportion of vascuiar tissue and/or scierenchyma, as measured in transverse sections (Wiison, 1976a, 6;Jurik, Cbabot & Cbabot, 1982;Pammenter, Drennan & Smitb, 1986). As for cell size, while it has sometimes been shown rhat leaies witb large ceils bad a low LSM (Wilson & Cooper, 1969;Dijkstra & Lambers, 1989o), tbiy does not seem to be a general rule (e.g. Pammenter et al, 1986).…”

Effects of Light and Nutrients on Leaf Size, CO2 Exchange, and Anatomy in Wild Strawberry (Fragaria virginiana)

“…However, in some cases changes in whole-leaf CO2 exchange have been correlated with changes in leaf anatomy. Wilson and Cooper (22)(23)(24)(25) found a negative correlation ofphotosynthetic rate with mesophyll cell size in different genotypes and experimental treatments of Lolium perenne L., although the relationship was not completely consistent. Nobel et al (15) found that changes in mesophyll cell surface area accounted for differences in CO2 exchange rates of Plectranthus parviflorus grown at several irradiances.…”