Morphophysiological changes of Acca sellowiana (Myrtaceae: Myrtoideae) saplings under shade gradient

Abstract

Understanding morphological and physiological changes under different light conditions in native fruit species in juveniles’ stage is important, as it indicate the appropriate environment to achieve vigorous saplings. We aimed to verify growth and morphophysiological changes under shade gradient in feijoa (Acca sellowiana (O. Berg) Burret) to achieve good quality saplings adequate to improve cultivation in orchards. The saplings were grown for twenty-one-month under four shading treatments (0%, 30%, 50%, and 80%). Growth, photosynthetic pigments, gas exchanges, chlorophyll fluorescence, and leaf anatomy parameters were evaluated. Saplings under full sun and 30% shade had higher height and diameter growth and dry mass accumulation due to higher photosynthesis rate. As main acclimatization mechanisms in feijoa saplings under 80% shade were developed larger leaf area, reduced leaf blade thickness, and enhanced quantum yield of photosystem II. Even so, the net CO2 assimilation and the electron transport rate was lower and, consequently, there was a restriction on the growth and dry mass in saplings under deep shade. Therefore, to obtain higher quality feijoa saplings, we recommend that it be carried out in full sun or up to 30% shade, to maximize the sapling vigor in nurseries and, later, this light environment can also be used in orchards for favor growth and fruit production.

Campomanesia xanthocarpa (Myrtaceae: Myrtoideae) seedlings reveal morpho-physiological plasticity under shade conditions

“…The reduced quantum yield of photosystem II in the non-shade treatment indicated that despite high PAR, not all sunlight absorbed was transformed into photochemical products, but this solar energy was dissipated as heat; it is well known that the excessive energy dissipation prevents photosynthetic apparatus disturbance in the thylakoids (Taiz et al, 2014). In addition to this, the higher ETR observed in species grown in full sunlight conditions in the Atlantic Forest demonstrates no damage in the reaction centers in photosystem I (Dos Anjos et al, 2012;Cerqueira et al, 2018;Silva et al, 2022). Our results regarding photosynthetic efficiency under shade treatments were congruent with previous research on the guabiroba plants ( Bartieres et al, 2021).…”

Morpho-physiological and anatomical responses to shade avoidance are exhibited in Surinam cherry seedlings

“…According to the results evaluated by Mielke and Schaffer (2010) [2], the biomass rose due to the partial effect of a high-light environment in E. uniflora seedlings. Similar morphological results were also established in Acca sewolliana [10] and Araucaria angustifolia [8], demonstrating that all these plants are sun-demanding species.…”

“…Previous studies portrayed that minimum radiance induces higher chlorophyll pigment content per mass unit [11], being part of the shade stress response. Various tree species displayed different chlorophyll levels under shade conditions [7,10,31]. Otherwise, although carotenoids are crucial in photoprotection under high-light regimes, some plants do not change these contents under light stress [31].…”

“…Evidence suggests that E. uniflora seedlings exposed to various sunlight conditions can adjust their morphological and physiological characteristics to attain solar irradiation more efficiently [7][8][9][10]. These modifications are called acclimation or phenotypic plasticity, as a genotype's ability to produce diverse phenotypes under different environmental stresses [11].…”

Ecophysiological mechanisms and growth of Inga vera Willd. under different water and light availability

“…The increase in leaf area under conditions of lower solar radiation can be considered phenotypic plasticity, as the increase in leaf area optimizes the interception of light rays and thus results in more efficient production of photoassimilates (Poorter et al, 2019;Reis et al, 2022;Silva et al, 2022). Furthermore, during the evaluations, we observed that plants with low water availability showed a reduction in leaf area, which remained stable even after supplying a greater amount of water, as observed in REC.…”