Understanding the Physiological Responses of a Tropical Crop (Capsicum chinense Jacq.) at High Temperature

Abstract

Temperature is one of the main environmental factors involved in global warming and has been found to have a direct effect on plants. However, few studies have investigated the effect of higher temperature on tropical crops. We therefore performed an experiment with a tropical crop of Habanero pepper (Capsicum Chinense Jacq.). Three growth chambers were used, each with 30 Habanero pepper plants. Chambers were maintained at a diurnal maximum air temperature (DMT) of 30 (chamber 1), 35 (chamber 2) and 40°C (chamber 3). Each contained plants from seedling to fruiting stage. Physiological response to variation in DMT was evaluated for each stage over the course of five months. The results showed that both leaf area and dry mass of Habanero pepper plants did not exhibit significant differences in juvenile and flowering phenophases. However, in the fruiting stage, the leaf area and dry mass of plants grown at 40°C DMT were 51 and 58% lower than plants at 30°C DMT respectively. Meanwhile, an increase in diurnal air temperature raised both stomatal conductance and transpiration rate, causing an increase in temperature deficit (air temperature – leaf temperature). Thus, leaf temperature decreased by 5°C, allowing a higher CO2 assimilation rate in plants at diurnal maximum air temperature (40°C). However, in CO2 measurements when leaf temperature was set at 40°C, physiological parameters decreased due to an increase in stomatal limitation. We conclude that the thermal optimum range in a tropical crop such as Habanero pepper is between 30 and 35°C (leaf temperature, not air temperature). In this range, gas exchange through stomata is probably optimal. Also, the air temperature–leaf temperature relationship helps to explain how temperature keeps the major physiological processes of Habanero pepper healthy under experimental conditions.

Bacillus spp. inoculation improves photosystem II efficiency and enhances photosynthesis in pepper plants

“…CO 2 assimilation rate (A N ), stomatal conductance (g s ) and transpiration (E) were measured using an infrared gas analyzer (IRGA; LICOR, LI-6400, Lincoln, Nebraska, USA). Water use efficiency (WUE) was calculated as A N /E (Garruña- Hernández et al, 2014). Measurements were performed in the same leaves used in chlorophyll fluorescence measurement.…”

“…In particular, Habanero pepper (Capsicum chinense Jacq.) grows in wide temperature range, and has therefore been used in studies of plant stress (Garruña-Hernández et al, 2014;Valle-Gough et al, 2015).…”

Pepper Photosynthesis, Stomatal Conductance, Transpiration, and Water Use Efficiency Differ with Variety, Indigenous Habitat, and Species of Origin

“…Abiotic factors such as low temperatures, high temperatures, salt stress, drought (Serrano et al, 2017), and waterlogging can limit pepper yield (Ou and Zou, 2012;Zhai et al, 2016). For instance, optimal temperatures for pepper photosynthesis range from 25 to 35°C, and temperatures outside this range can limit the yield; for example, C. chinense flower abortion increased 2-fold and fruit set decreased 3-fold when greenhouse temperatures were increased from 30 to 40°C (Garruna-Hernandez et al, 2014). Erickson and Markhart (2002) showed that Capcisum flower abortion after pollination was particularly sensitive to high temperatures (33°C).…”

Perceived effects of climate change on profit efficiency among small scale chili pepper marketers in Benue State, Nigeria

“…High temperatures affect many aspects of plant physiology and growth, which in turn may have a direct or indirect effect on crop yield (Erickson and Markhart 2001;Bhutia et al 2018). Many studies have shown the direct impact of increased or decreased temperature in the production of chili pepper (Garruna-Hernandez et al 2014;Bhutia et al 2018). Pepper that is grown under high temperature (33°C) shows reduced fruit set (Yanez-Lopez et al 2012;Bhutia et al 2018), and flower malformation when grown in temperatures below 18°C resulting in the formation of parthenocarpic fruits and reduced fruit set (Aloni et al 1999;Bhutia et al 2018).…”