Role of abscisic acid in legumes under abiotic stress - Legumes Under Environmental Stress: Yield, Improvement and Adaptations - page 145

Chapter 10

Role of abscisic acid in legumes under
abiotic stress

Analia Llanes, Genoveva Devinar and Virginia Luna
Laboratorio de Fisiología Vegetal, Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales,
Universidad Nacional de Río Cuarto, Río Cuarto, Argentina

10.1 Introduction

by the anticipated increase of 3-5°C in average surface
temperatures in the next 50-100 years; such climate
predictions also show an increased frequency of drought,
flood and heatwaves (Mittler & Blumwald, 2010).
However, some of the negative impact of climatic changes
on food production could be alleviated by adaptation of
crop plants and by relatively inexpensive changes, such
as shifting planting dates or switching from an existing
crop variety.
One of the main types of crops worldwide are legumes.
These plants have important impacts on farming, and
also on animal and human nutrition and health
(Graham & Vance, 2003). Legumes represent the third
largest group of angiosperms and are the second largest
group of food and feed crops grown globally. Around
12-15% of available arable land is cultivated for
legumes, which account for more than 25% of the
world's primary crop production; annual global produc-
tion of grain legumes is 247 million tonnes (Jensen et al.,
2007). Among the more important leguminous food
and feed crop species are soybean, pea, clover, chickpea,
alfalfa and mung bean. Nitrogen fixation allows legumes
to have tissue with a high content of protein; thus,
legumes are used in agricultural practice to amend
deficiencies of nitrogen in soil.
Adaptation of legumes will determine the future
severity of the effects of climatic change. Furthermore,
some relatively inexpensive agricultural practices, such
as shifting planting dates or switching from an existing
crop variety, may moderate the negative effects of
climatic change. Several environmental factors such

Plants are sessile organisms and have to regulate their
growth and development to allow them to respond to
numerous external stimuli and constantly changing
living conditions. These conditions include a complex
set of biotic and abiotic environmental stresses, and
plants must be able to response with compensatory
mechanisms to limit or repair the impact of such
stresses (Peleg & Blumwald, 2011). As the world's
human population continues to expand (increasing
from about 6 billion people in 2000 to a projected 10
billion in 2050), so has the need to grow more food,
which requires an increase in the area of land under
cultivation as well as in land productivity measured as
yield per hectare. In this regard, the UN Food and
Agriculture Organization (FAO) has indicated that the
average world crop yield will need to reach 5 t/ha from
its present 3 t/ha. Furthermore, less than 10% of the
arable lands in the world may be free from adverse abi-
otic conditions (Dudal, 1976). Environmental concerns
about the great amounts of chemical fertilizers needed
and the increasing cost of fossil fuels as well as the emer-
gence of biofuels competing with food production, may
further complicate the situation.
In addition, changing climatic conditions, with
increased temperatures and evapotranspiration losses,
and decreasing rainfall, will have a particularly negative
effect on the soils and productivity of many developing
regions (Rijsberman, 2006; Lobell et al., 2008). In fact,
the global agricultural systems will be drastically affected