Agriculture Reference
In-Depth Information
by providing a means to increase crop yield and quality in an agricultural context
(Bergelson and Roux
2010
). Many elements in the soil serve as mineral nutrients
for plants. Among them, nitrogen (N), potassium (K), phosphorus (P) and sulfur
(S) are required in relatively large amounts for plant growth. Therefore, deficiency
in any one of these four elements in the field affects plant metabolism, and shows a
dramatic impact on yield, nutritional quality and taste as well as pathogen and pest
resistance in crops (Laegreid et al.
1999
). In developed countries, plentiful amounts
of fertilisers are applied, resulting in abundant inorganic nutrients in the ecosystem
that may cause disturbance in normal bio-geochemical cycles of nutrients. How-
ever, this trend is being challenged by the current emphasis on developing more
efficient cultivars for sustainable, low-input agriculture, fuelled by increasing cost
of fertilisers, restrictions to minimise environmental impact and the increased use
of poor quality land (Rengel and Damon
2008
). Some plant species and genotypes
within species have a capacity to grow and yield well on soils with a low level of
available nutrients; these species and genotypes are considered as tolerant to
nutrient deficiency and with high nutrient use efficiency (NUE; Good et al.
2004
).
The NUE can be described as the proportion of potential yield that can be achieved
under that mineral deficiency availability. It is the product of nutrient uptake
efficiency (NUpE) and nutrient utilisation efficiency (NUtE), which is the optimal
combination between nutrient assimilation efficiency (NAE) and nutrient
remobilisation efficiency (NRE) (Masclaux-Daubresse et al.
2010
). Improving
each crop individually requires a global knowledge of the different mechanisms
that control all the steps involved in nutrient management in plants, and also a good
knowledge of the specificities of each plant species in terms of metabolism
(Chardon
2012
).
Investigation of Natural Variation in Plants Reveals
Different Strategies of Response to Nutrient Limitation
A huge natural variation exists between individuals within a given plant species,
affecting for example the colour or the shape of leaves, grain composition, seed
dormancy, flowering date or maturity date. These variations could have an impor-
tant impact on yield or quality of their products in crops, fruit trees and forestry
management species (Saisho et al.
2011
; Arikita et al.
2013
; Eduardo et al.
2010
;
Łata et al.
2005
; Robinson et al.
2012
). Some developmental traits, such as
flowering time or seed dormancy, have drawn particular attention, partly because
they are of applied interest to crop breeding, and partly because they are easy to
investigate (Shindo et al.
2007
). Natural variation involves not only the morphology
of plants but also their behaviour when facing contrasted environments. The
responses or growth-related traits to different environmental scenarios are genotype
dependent. Hence, natural variation in plants provides an interesting and valuable
source of genetic diversity to study plant responses to environmental factors. The
plant
s capacity to adapt to environmental constraints is called plant plasticity. It
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