How the long-life span leaves of Ouratea castaneifolia Engl. (Ochnaceae) differ in distinct light conditions

Abstract

Plants respond to variation in luminosity leading to the existence of distinct leaf traits in plants that inhabit the understory, edge, and canopy of tropical forests. In the present work, the long-life leaves of Ouratea castaneifolia Engl. (Ochnaceae) in forest edge and understory were evaluated. Leaves of 20 individuals were collected from each habitat. Median regions of leaves from the third node were fixed in FAA. Freehand-cut transverse sections were stained in astra blue and safranin. The thickness of tissues, leaf area, specific leaf mass, and relative water content were quantified. Quantum yield of photosynthesis was measured by Fv/Fm, and instantaneous light response curves were performed to extract ETR max , PAR sat , and DF/Fm 0 sat. Quantification of photosynthetic pigments was also performed. Leaf area was lower at the forest edge, while the specific leaf mass was higher. No structural differences or differences in relative water content were observed between individuals of the two environments. The thicknesses of the cuticle on the adaxial surface, the epidermal cells on the abaxial surface, and the palisade and spongy parenchyma were greater in individuals at the forest edge. The values of Fv/ Fm were around 0.8 in the predawn. In midday, higher values of Fv/Fm were observed in individuals located in the understory. Individuals of the understory had higher levels of chlorophyll a, chlorophyll b, and total chlorophyll. The morphological traits were the most plastic, but modulations in both morphology and pigment concentration may explain the maintenance of a similar predawn quantum yield between environments.

Morphophysiological adjustments to shade of jaboticaba tree saplings

“…The thinner leaves on shade-grown plants allow for better diffuse light distribution across the plant canopy allowing photosynthesis to occur more efficiently throughout the entire plant (Brodersen & Vogelmann, 2010). On the other hand, the increase of palisade and spongy parenchyma thickness in full sun and 30% shade was responsible for homogenization of the distribution and better use of light, minimizing the damage caused by the high light supply (Barbosa-Campos et al, 2018).…”

Promoter replacement of ANT1 induces anthocyanin accumulation and triggers the shade avoidance response through developmental, physiological and metabolic reprogramming in tomato

“…The gas exchange parameters were measured as described [ 60 ]. The photosynthetic light response ( A/PPFD ) and internal CO 2 partial pressure ( A/C i ) response curves were obtained as described [ 61 ]. Furthermore, taking as a basis the data obtained by the A/C i curves we were able to estimate mesophyll conductance ( g m ) and CO 2 in chloroplastic stroma ( C c ) [ 62 ].…”

Response to water‐deficit following waterlogging varies among ecotypes of subterranean clover (Trifolium subterraneum ssp. yanninicum), a waterlogging‐tolerant annual pasture legume

“…As the interface between the plant and its aerial environment, the leaf is the most plastic plant organ, adjusting physiologically and morphologically at small timescales under variable environmental conditions, including water availability (Barbosa‐Campos et al, 2018; Craven et al, 2011). Hence, leaf growth and physiological response are critical to understand plant performance to soil moisture stress.…”