Biomass and Leaf Acclimations to Ultraviolet Solar Radiation in Juvenile Plants of Coffea arabica and C. canephora

• Published in: Plants (Basel) Vol. 10; no. 4; p. 640
• Main Authors: Bernado, Wallace de Paula, Rakocevic, Miroslava, Santos, Anne Reis, Ruas, Katherine Fraga, Baroni, Danilo Força, Abraham, Ana Cabrera, Pireda, Saulo, Oliveira, Dhiego da Silva, Cunha, Maura Da, Ramalho, José Cochicho, Campostrini, Eliemar, Rodrigues, Weverton Pereira
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 28-03-2021; MDPI
• Subjects: Acclimation; Acclimatization; Binding sites; Biomass; Chlorophyll; Coffea arabica; Coffea canephora; Coffee; Energy consumption; Energy dissipation; Experiments; Flowers & plants; fluorescence; Genotypes; leaf anatomy; leaf pigments; Leaves; Metabolism; Morphology; Parenchyma; Photochemicals; Photochemistry; Physiology; Plant biomass; Plant growth; Plants; Precipitation; Radiant flux density; Solar radiation; Species; Stomata; Thickening; Ultraviolet radiation; UV-A; UV-B; Brazil; United States > US; plant growth; UV-B; leaf anatomy; UV-A; leaf pigments; fluorescence
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants10040640

Despite the negative impacts of increased ultraviolet radiation intensity on plants, these organisms continue to grow and produce under the increased environmental UV levels. We hypothesized that ambient UV intensity can generate acclimations in plant growth, leaf morphology, and photochemical functioning in modern genotypes of
and
. Coffee plants were cultivated for
six months in a mini greenhouse under either near ambient (UVam) or reduced (UVre) ultraviolet regimes. At the plant scale,
was substantially more impacted by UVam when compared to
, investing more carbon in all juvenile plant components than under UVre. When subjected to UVam, both species showed anatomic adjustments at the leaf scale, such as increases in stomatal density in
, at the abaxial and adaxial cuticles in both species, and abaxial epidermal thickening in
, although without apparent impact on the thickness of palisade and spongy parenchyma. Surprisingly,
showed more efficient energy dissipation mechanism under UVam than
. UVam promoted elevated protective carotenoid content and a greater use of energy through photochemistry in both species, as reflected in the photochemical quenching increases. This was associated with an altered chlorophyll
ratio (significantly only in
) that likely promoted a greater capability to light energy capture. Therefore, UV levels promoted different modifications between the two
sp. regarding plant biomass production and leaf morphology, including a few photochemical differences between species, suggesting that modifications at plant and leaf scale acted as an acclimation response to actual UV intensity.