Supplementary Calcium Restores Peanut (Arachis hypogaea) Growth and Photosynthetic Capacity Under Low Nocturnal Temperature.

Qiaobo Song,Yinglong Chen,Xiaori Han,Jean Wan Hong Yong,Jiayin Pang,Qingwen Shi,Di Wu,Tianlai Li,Clément Gille,Chunming Bai,Hans Lambers,Yifei Liu,Kadambot H M Siddique

doi:10.3389/fpls.2019.01637

Abstract

Peanut (Arachis hypogaea L.) is a globally important oil crop, which often experiences poor growth and seedling necrosis under low nocturnal temperatures (LNT). This study assessed the effects of supplementary calcium (Ca2+) and a calmodulin inhibitor on peanut growth and photosynthetic characteristics of plants exposed to LNT, followed by recovery at a higher temperature. We monitored key growth and photosynthetic parameters in a climate-controlled chamber in pots containing soil. LNT reduced peanut growth and dry matter accumulation, enhanced leaf nonstructural carbohydrates concentrations and non-photochemical quenching, decreased the electron transport rate, increased the transmembrane proton gradient, and decreased gas exchange rates. In peanuts subjected to LNT, foliar application of Ca2+ restored growth, dry matter production and leaf photosynthetic capacity. In particular, the foliar Ca2+ application restored temperature-dependent photosynthesis feedback inhibition due to improved growth/sink demand. Foliar sprays of a calmodulin inhibitor further deteriorated the effects of LNT which validated the protective role of Ca2+ in facilitating LNT tolerance of peanuts.

Highlights

Arachis hypogaea Leaf stomatal limitation (Ls)., originally from tropical South America (Bolivia and adjoining countries), is primarily grown in tropical and subtropical agro-climatic areas of Asia, Africa, Oceania, and the Americas
Effect of Exogenous Calcium (Ca2+) and a Calmodulin Inhibitor (TFP) on Peanut Growth After 5 Days of Low Nocturnal Temperature Stress Followed by 5 Days of Recovery
Our results suggested that low nocturnal temperature (LNT) stress directly inhibits peanut growth and source-to-sink sugar transport, and induces the accumulation of nonstructural carbohydrates in leaves (Figure 2), which is consistent with the previous findings in maize (Adams et al, 2013)

Summary

Introduction

Arachis hypogaea L. (peanut or groundnut), originally from tropical South America (Bolivia and adjoining countries), is primarily grown in tropical and subtropical agro-climatic areas of Asia, Africa, Oceania, and the Americas. (peanut or groundnut), originally from tropical South America (Bolivia and adjoining countries), is primarily grown in tropical and subtropical agro-climatic areas of Asia, Africa, Oceania, and the Americas. It is an important oil crop globally, providing the main source of edible oil and protein in many developing countries (Prasad et al, 2003; Bertioli et al, 2016). Peanut often experiences poor growth and seedling necrosis under LNT stress, which severely reduces peanut yield and seed quality (Bagnall et al, 1988; Wan 2003,; Liu et al, 2013)

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Conclusion