Plant tolerance to high temperature in a changing environment: scientific fundamentals and production of heat stress-tolerant crops

Abstract

Global warming is predicted to have a general negative effect on plant growth due to the damaging effect of high temperatures on plant development. The increasing threat of climatological extremes including very high temperatures might lead to catastrophic loss of crop productivity and result in wide spread famine. In this review, we assess the impact of global climate change on the agricultural crop production. There is a differential effect of climate change both in terms of geographic location and the crops that will likely show the most extreme reductions in yield as a result of expected extreme fluctuations in temperature and global warming in general. High temperature stress has a wide range of effects on plants in terms of physiology, biochemistry and gene regulation pathways. However, strategies exist to crop improvement for heat stress tolerance. In this review, we present recent advances of research on all these levels of investigation and focus on potential leads that may help to understand more fully the mechanisms that make plants tolerant or susceptible to heat stress. Finally, we review possible procedures and methods which could lead to the generation of new varieties with sustainable yield production, in a world likely to be challenged both by increasing population, higher average temperatures and larger temperature fluctuations.

Keywords: food security; global warming; heat tolerance; productivity; yield.

FIGURE 1

Global temperature and population trends. (A) Reduction in yield increases of major crops since 1961; wheat (red graph), rice (yellow graph), maize (blue graph). Data taken from FAO-STAT (). (B) Global increases in temperature since 1880. Data taken from Hansen et al. (2012). (C) Population increase since 1960. Data taken from the US Census Bureau (). (D) Regional food security risk areas. Data taken from (E) Regional temperature increase. Data taken from the Hadely Centre, UK Met Office (). (F) Changes in regional agricultural productivity. Data taken from the Bard Center for Environmental Policy ().

FIGURE 2

Environmental signaling pathways with external cues and internal repercussions. Environmental cues are on the left in red backgrounds with initial cellular effects with green backgrounds and the organismal signals are shown with blue background.

FIGURE 3

Flower development and pollen viability of tolerant (left) and sensitive tomato genotypes (right). The top shows inflorescences of a heat-tolerant genotype on the left (A) and a sensitive genotype on the right (B). In the second panel, the morphology of the anther cones is shown for both genotypes (C) and (D). Below (E–H) in vitro pollen germination under standard conditions (E; heat-tolerant genotype, G; heat-sensitive) and high temperature for both genotypes (F; heat-tolerant genotype, H; heat-sensitive).