Anatomy and Morphology of Sun- and Shade-grown Ficus benjamina1

Abstract

Weeping fig (Ficus benjamina L.) plants were greenhouse-grown under full sun or 75% light exclusion. Shade-grown leaves were larger, thinner, flatter, and darker green than sun-grown leaves. Sun- and shade-grown plants had the same total leaf area and were the same height. Shade-grown leaves had a single, poorly developed palisade layer with large chloroplasts dispersed throughout the palisade cells. Sun-grown leaves had one or two layers of well developed palisade cells with the chloroplasts aligned primarily along the radial walls. Stomatal density was greater in sun-grown leaves, but shade-grown leaves had more stomata per leaf.

Light Acclimation in Citrus Leaves. I. Changes in Physical Characteristics, Chlorophyll, and Nitrogen Content

“…In shade leaves, pigments seem to be more concentrated in the upper tissue layers than in those below. Differences in pigment distribution support the observations of others that shaded leaves tend to have more chlorophyll in the palisade tissues of the leaf (8,16). This arrangement likely enhances light harvesting efficiency, as leaves from low PPFD also were more horizontal whereas high PPFD leaves appeared somewhat folded along the midvein as previously observed by Monselise (20).…”

“…Since the majority of leaves in a tree canopy are growing under reduced light, higher 0 of shade leaves allows them to capitalize on existing Tight microclimates (18). Although the plasticity of 0 in sun and shade leaves has been described for many crops (20,24) native shrubs and trees (1,8,20), there is no available information on how 0 varies with the PPFD environment of citrus trees. This relationship can…”

Light Acclimatization Potential of Ficus benjamina1

“…Sun leaves at week 0 were thick, had multiple layers of palisade cells (Fig. 3A) and were characterized by other sun-adaptation features described previously (11). Chloroplasts within the palisade cells were aligned along the radial walls and did not stain heavily.…”

“…Leaves of shade-grown plants at week 0 were thin, had a single layer of palisade cells (Fig. 3E), and were characteristic of shade-adapted weeping fig leaves (11). No apparent changes within the mesophyll occurred in shade-grown leaves (Sh-SIE) after 12 weeks in the SIE (Fig.…”

“…Conover and Poole (8) suggested that little shade conversion of sun-grown foliage occurred during acclimatization, rather the advantage of acclimatization being the production of new shade-grown foliage and conversion of immature foliage. Light during development affects both leaf anatomy and physiology in weeping fig (11,12) and in other species (4,5,19). The extent to which light acclimatization can occur without concomitant changes in leaf anatomy is unknown.…”