diterpene synthesis in methylerythritol phosphate (MEP) pathway (Dudareva et al.
2013). Research is in the field of genetics on the allelopathic traits are not fully
explored by the plant breeders as the inheritance pattern of allelopathic characters are
very much complex, and to isolate and quantification of the allelochemicals in a
diverse germplasm collection, the task is limited because of the availability of
necessary high-throughput analytical techniques.
Olofsdotter et al. (1995) hypothesized that allelopathy may be polygenic in trait
and weakly associated with yield and yield-related characters in crops. The allelopathic chemicals are released in higher quantity to the environment that is stimulated
by stress conditions. The stressors may regulate the genes for the biosynthesis of
allelochemicals and release them to the environment (Einhellig 1996). If we acquire
more genetic information, the inheritance pattern of regulatory genes that are responsible for the synthesis and expression of allelochemicals that pave way to identify
the novel secondary metabolites to initiate breeding programs for developing allelopathic cultivars. Although genetic dissection of allelopathic traits is still in the
juvenile stage and will emerge into new frontiers of research to develop potential
bioherbicides, as an innovative outlook, molecular and bioinformatics-based
advanced research will shed light on the activation of gene and its transcriptional
and translational changes associated with stressors.
2.3.2 Environmental Factors
Environmental factors can precisely or obliquely affect the allelopathic pursuance of
a plant with an adaptive response to the environment. The plant functional characters
have been largely applied to analyses of species-specific traits, and the significance
of the terminology holds different dimensions when the plant is exposed to environmental stresses. Plants can receive and realize a range of external and internal
stimuli from their neighborhood settings, while environmental changes can influence
crop allelopathy and its functional characters (Rivoal et al. 2011). The environment
can alter allelopathy in the following means, viz., generating of allelopathic compounds (GxE interactions), their bioavailability, and their influence on target species.
Several studies have shown that the amount of allelochemicals produced and
released by plants is correlated to environmental factors (Paré and Tumlinson 1999,
Agrawal 2001). The key important environmental factors that can impact crop
allelopathy include UV radiation, temperature, water, nutrient availability, and
competition stress. For example, one of the valuable adaptive processes to enhance
UVB radiation is the augmented production of water-soluble phenolics in foliage
tissues under an elevated level of UVB radiation in herbaceous plants (Li et al.
2010a, b). The UVB radiation is transmitted by the reflective mechanism through the
epicuticular wax layer, and the UV rays reach the epidermal tissues and protect the
underlying tissues against harmful UVB radiation. Various factors, such as temperature extremes, deficiency of nutrients, and heavy metals, enhance the allelochemical
production in many plant species (Maqbool et al. 2013). Several sources of rain
leachates range significantly in their thwarting effects, and rain leachates from plant
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H. Palanivel et al.
2013). Research is in the field of genetics on the allelopathic traits are not fully
explored by the plant breeders as the inheritance pattern of allelopathic characters are
very much complex, and to isolate and quantification of the allelochemicals in a
diverse germplasm collection, the task is limited because of the availability of
necessary high-throughput analytical techniques.
Olofsdotter et al. (1995) hypothesized that allelopathy may be polygenic in trait
and weakly associated with yield and yield-related characters in crops. The allelopathic chemicals are released in higher quantity to the environment that is stimulated
by stress conditions. The stressors may regulate the genes for the biosynthesis of
allelochemicals and release them to the environment (Einhellig 1996). If we acquire
more genetic information, the inheritance pattern of regulatory genes that are responsible for the synthesis and expression of allelochemicals that pave way to identify
the novel secondary metabolites to initiate breeding programs for developing allelopathic cultivars. Although genetic dissection of allelopathic traits is still in the
juvenile stage and will emerge into new frontiers of research to develop potential
bioherbicides, as an innovative outlook, molecular and bioinformatics-based
advanced research will shed light on the activation of gene and its transcriptional
and translational changes associated with stressors.
2.3.2 Environmental Factors
Environmental factors can precisely or obliquely affect the allelopathic pursuance of
a plant with an adaptive response to the environment. The plant functional characters
have been largely applied to analyses of species-specific traits, and the significance
of the terminology holds different dimensions when the plant is exposed to environmental stresses. Plants can receive and realize a range of external and internal
stimuli from their neighborhood settings, while environmental changes can influence
crop allelopathy and its functional characters (Rivoal et al. 2011). The environment
can alter allelopathy in the following means, viz., generating of allelopathic compounds (GxE interactions), their bioavailability, and their influence on target species.
Several studies have shown that the amount of allelochemicals produced and
released by plants is correlated to environmental factors (Paré and Tumlinson 1999,
Agrawal 2001). The key important environmental factors that can impact crop
allelopathy include UV radiation, temperature, water, nutrient availability, and
competition stress. For example, one of the valuable adaptive processes to enhance
UVB radiation is the augmented production of water-soluble phenolics in foliage
tissues under an elevated level of UVB radiation in herbaceous plants (Li et al.
2010a, b). The UVB radiation is transmitted by the reflective mechanism through the
epicuticular wax layer, and the UV rays reach the epidermal tissues and protect the
underlying tissues against harmful UVB radiation. Various factors, such as temperature extremes, deficiency of nutrients, and heavy metals, enhance the allelochemical
production in many plant species (Maqbool et al. 2013). Several sources of rain
leachates range significantly in their thwarting effects, and rain leachates from plant
102
H. Palanivel et al.