Seasonal Changes in Morphology and Anatomy of Field‐grown Soybean Leaves¹

Abstract

The objective of this study was to examine seasonal changes in specific leaf weight (SLW) of soybean (Glycine max [L.] Merrill) leaves and to compare these with changes in leaf area, thickness, and anatomical features. For individual leaves, SLW generally decreased as leaf area increased, and then increased as leaves thickened. In most cases, leaves thickened after the period of greatest leaf area expansion. Specific leaf weight then decreased as leaves senesced. In general, the maximum SLW achieved by each leaf was successively greater with each successive node. Similarly, leaves at upper nodes were thicker than those of the lower nodes. Leaf thicken. ing was largely the result of concurrent thickening of palisade and spongy mesophyll tissues. An important discovery was that in the uppermost, thickest leaves a third layer of palisade mesophyll cells was formed 'by ~iericlinal division in the outermost palisade layer. The nal SLW and leaf thickness obtained were modified by solar radiation levels during the period of leaf development. Differences in radiation distribution seemed to accentuate differences among leaves in 1976 studies and reduce differences in 1977.

Physiological comparisons of two soybean cultivars differing in canopy photosynthesis. II. Variation in specific leaf weight, nitrogen, and protein components

“…The large difference observed in SLW with changing canopy position is in agreement with the responses observed in other studies [ 15,16]. Similarly, Bowes et al [4] found that greater light intensity during growth was responsible for increaed leaf AP, RuBPCase activity, and SLW.…”

“…The correlations between SLW and these same parameters of leaf protein status per unit leaf weight were not significant for any year. Since greater SLW has been reported to be associated with more layers of palisade and mesophyll cells [6,15], it appears that greater amounts of photosynthetic tissues, and hence, increased concentrations of photosynthetic enzymes per unit leaf area are a result of increased SLW. As mentioned, Bowes et al [4] found that SLW (fresh weight basis) and RuBPCase activity per unit leaf area were both increased in response to progressively greater light intensity.…”

The effect of leaf size on mutual shading and cultivar differences in soybean leaf photosynthetic capacity

“…Hesketh et al (1981) found Hodgson and Amsoy to have higher rates than Clark and Lincoln. Sinclair (1980) reported that Amsoy had higher rates of photosynthesis than Lincoln. Dornhoff and Shibles (1971) found Amsoy to have higher rates than Lincoln, with Mandarin intermediate.…”

Microclimate effects on plant morphology

“…In both species leaf thickening was associated with a concurrent increase in the amount of mesophyll tissue, which is consistent with observations by Lugg and Sinclair (1980). As with leaf thickness, changes in anatomical characteristics such as VR and AR, reflected the variations in light environment during and after areal leaf expansion.…”