Kaolin Film Increases Gas Exchange Parameters of Coffee Seedlings During Transference From Nursery to Full Sunlight

Deivisson Pelegrino de Abreu; Newton de Matos Roda; Gideao Pelegrino de Abreu; Wallace de Paula Bernado; Weverton Pereira Rodrigues; Eliemar Campostrini; Miroslava Rakocevic

doi:10.3389/fpls.2021.784482

Kaolin Film Increases Gas Exchange Parameters of Coffee Seedlings During Transference From Nursery to Full Sunlight

Front Plant Sci. 2022 Jan 7:12:784482. doi: 10.3389/fpls.2021.784482. eCollection 2021.

Authors

Deivisson Pelegrino de Abreu¹, Newton de Matos Roda², Gideao Pelegrino de Abreu³, Wallace de Paula Bernado¹, Weverton Pereira Rodrigues^{1

4}, Eliemar Campostrini¹, Miroslava Rakocevic¹

Affiliations

¹ Laboratory for Plant Genetic Breeding (LMGV), State University of the North Fluminense Darcy Ribeiro, Rio de Janeiro, Brazil.
² Department of Exact, Environmental and Technological Sciences (CEATEC), Pontifical Catholic University of Campinas, Campinas, Brazil.
³ Business School and Polytechnic School, MBA in Business Technology, Data Science and Big Data, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil.
⁴ Center of Agricultural, Natural and Literary Sciences, State University of the Tocantina Region of Maranhão (UEMASUL), Estreito, Maranhão, Brazil.

Abstract

Increases in water use efficiency (WUE) and the reduction of negative impacts of high temperatures associated with high solar radiation are being achieved with the application of fine particle film of calcined and purified kaolin (KF) on the leaves and fruits of various plant species. KF was applied on young Coffea arabica and Coffea canephora plants before their transition from nursery to full sunlight during autumn and summer. The effects of KF were evaluated through the responses of leaf temperature (T_leaf), net CO₂ assimilation rate (A), stomatal conductance (g _s), transpiration (E), WUE, crop water stress index (CWSI), index of relative stomatal conductance (I_g), initial fluorescence (F₀), and photosynthetic index (PI) in the first 2-3 weeks after the plant transitions to the full sun. All measurements were performed at midday. In Coffea plants, KF decreased the T_leaf up to 6.7°C/5.6°C and reduced the CWSI. The plants that were not protected with KF showed lower A, g _s, E, and I_g than those protected with KF. C. canephora plants protected with KF achieved higher WUE compared with those not protected by 11.23% in autumn and 95.58% in summer. In both Coffea sp., KF application reduced F₀, indicating reduced physical dissociation of the PSII reaction centers from the light-harvesting system, which was supported with increased PI. The use of KF can be recommended as a management strategy in the transition of Coffea seedlings from the nursery shade to the full sunlight, to protect leaves against the excessive solar radiation and high temperatures, especially in C. canephora during the summer.

Keywords: chlorophyll fluorescence; leaf photosynthesis; leaf transpiration; thermography; water management.