Morphoanatomical and physiological mechanisms of heliconia genotypes in response to varied solar irradiation conditions: The key to successful cultivation in sunny tropical regions

• Published in: Scientia horticulturae Vol. 337; p. 113511
• Main Authors: da Silva Souza, Geisse Carla, de Souza, Rafaela Ribeiro, da Silva, Raphael Reis, de Souza, Afonso Ricardo, Toro-Herrera, Mayra Alejandra, de Figueredo, Heberte Fernandes, Ferreira, Clébio Pereira, Borges, Mônica Cristina Rezende Zuffo, de Paiva Neto, Vespasiano Borges, Beckmann-Cavalcante, Márkilla Zunete
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-11-2024
• Subjects: Gas exchange; Heliconiaceae; Leaf anatomy; Luminosity; Tropical flowers; Luminosity; Heliconiaceae; Gas exchange; Tropical flowers; Leaf anatomy
• ISSN: 0304-4238
• DOI: 10.1016/j.scienta.2024.113511

•Heliconia plants grown in shade show improved growth and development.•Heliconia photosynthesis does not always correlate with thicker leaves.•The genotypes H. bihai and H. rostrata show lower tolerance to high solar irradiation.•The cultivars Golden Torch, Red Opal, and H. rauliniana show more tolerance to high solar irradiation.
Heliconias are, species of tropical flowers that have become increasingly attractive around the world due to their potential for commercial exploitation and ease of cultivation. However, their sensitivity to high levels of solar radiation makes their cultivation challenging in tropical and semiarid regions under full sun. Furthermore, there is a dearth of information on the morphophysiological mechanisms that enable heliconia genotypes to acclimate to high solar irradiation under field conditions. In this context, this research aimed to assess the impact of high solar irradiation on the anatomical and physiological traits of five heliconia genotypes (Heliconia psittacorum x H. spathocircinata cv. Golden Torch; H. psittacorum cv. Red Opal; H. bihai cv Lobster Claw Two; H. rauliniana and H. rostrata) grown under different levels of solar irradiation (direct exposure to the sun (FS) and 50 % shading (SH)). Cultivation in full sun (FS) led to significant changes such as reduced total leaf area, height, adaxial hypodermis, and decreased carboxylation efficiency. On the other hand, the shaded environment (SH) promoted an increase in leaf area, height, and carboxylation efficiency. Despite the general trend observed in FS or SH, the detailed results revealed considerable variations among genotypes. Thus, while some genotypes showed consistent reductions in growth in response to high levels of irradiation, others showed a less pronounced response. Our findings suggest that solar irradiation levels not only induce changes in the leaf expansion, density, and stomatal index of heliconia plants but also cause anatomical and functional adjustments in the structural elements of the leaves that are related to optical properties and carboxylation efficiency. Furthermore, genotypes with greater acclimatization ability and tolerance to high solar irradiance show more efficient stomatal regulation, which allows them to maximize photosynthesis and water use under these conditions. H. bihai and H. rostrata showed more sensitivity to cultivation in FS; therefore, the cultivation and commercial exploitation of these genotypes in regions with high incidence of solar irradiation require the use of shading. In contrast, the cultivars Golden Torch, Red Opal, and H. rauliniana exhibited notable tolerance to high levels of solar irradiation. Therefore, cultivating these genotypes in regions with high solar irradiation could eliminate the need for shading, making them ideal for use as cut flowers.
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