Yield, Physiological Performance, and Phytochemistry of Basil (Ocimum basilicum L.) under Temperature Stress and Elevated CO2 Concentrations.

T Casey Barickman,Wei Gao,Akanksha Sehgal,C Hunt Walne,K Raja Reddy,Omolayo J Olorunwa

doi:10.3390/plants10061072

T Casey Barickman, Wei Gao + Show 4 more

Open Access

https://doi.org/10.3390/plants10061072

Copy DOI

Abstract

Early season sowing is one of the methods for avoiding yield loss for basil due to high temperatures. However, basil could be exposed to sub-optimal temperatures by planting it earlier in the season. Thus, an experiment was conducted that examines how temperature changes and carbon dioxide (CO2) levels affect basil growth, development, and phytonutrient concentrations in a controlled environment. The experiment simulated temperature stress, low (20/12 °C), and high (38/30 °C), under ambient (420 ppm) and elevated (720 ppm) CO2 concentrations. Low-temperature stress prompted the rapid closure of stomata resulting in a 21% decline in net photosynthesis. Chlorophylls and carotenoids decreased when elevated CO2 interacted with low-temperature stress. Basil exhibited an increase in stomatal conductance, intercellular CO2 concentration, apparent quantum yield, maximum photosystem II efficiency, and maximum net photosynthesis rate when subjected to high-temperature stress. Under elevated CO2, increasing the growth temperature from 30/22 °C to 38/30 °C markedly increased the antioxidants content of basil. Taken together, the evidence from this research recommends that varying the growth temperature of basil plants can significantly affect the growth and development rates compared to increasing the CO2 concentrations, which mitigates the adverse effects of temperature stress.

Highlights

Climate change remains an important challenge affecting the attainment of global food security as it negatively impacts the growth and development of crops
Atmospheric CO2 and temperature are critical in the photosynthesis, physiological, and developmental processes that occur in many crops, especially
Conflicting with the pattern of changes of chlorophyll contents, total phenolic reduced (7%) in basil plants subjected to the interactions of high-temperature stress an elevated CO2 (Figure 2), whereas a significant increase of 10% was observed under low temperature at elevated CO2

Summary

Introduction

Climate change remains an important challenge affecting the attainment of global food security as it negatively impacts the growth and development of crops. Several studies have demonstrated higher atmospheric carbon dioxide (CO2 ) concentrations, extreme temperature conditions, and other extreme weather events as evidence of climate change [1,2]. Global atmospheric CO2 is rising (above 415 ppm in 2020). It is projected by climate models to reach the range of 540 to 970 ppm by 2100 because of human activities, declining carbon sinks, and natural global cycles [3,4]. Recent climate models have predicted that global air temperature may experience increments in the range of 1.5 and 4.5 ◦ C in the century due to the increasing levels of atmospheric CO2 and other greenhouse gases at an alarming rate [1,5]. Atmospheric CO2 and temperature are critical in the photosynthesis, physiological, and developmental processes that occur in many crops, especially

Objectives

Methods

Results

Discussion

Conclusion