Green gram (Vigna radiata), also called Mung bean, is a pulse
crop belonging to the botanical family Fabaceae. It is a warm-season,
frost-intolerant plant suitable for planting in temperate, subtropical, and
tropical regions. The optimal temperature for mung bean germination and growth
is 15-18 °C. It has high adaptability to various soil types, with the best soil
pH between 6.2 and 7.2. Since it is a short-day plant, long-day conditions will
delay its flowering and podding.
Environmental stress is a major area of scientific concern because
it constrains crop productivity. Anthropogenic activities have further worsened
the situation. Abiotic stresses, such of stable food crops. Salinity is one of
the most important abiotic stress factors limiting plant growth and
productivity (Flowers, 2004). High exogenous salt concentrations affect seed
germination, induce water deficit, and cause ionic imbalance, resulting in ion
toxicity and osmotic stress (Khan and Panda, 2009). According to estimates from
FAQs, over 6% of the world’s land is affected by salinity. Thus, salinity
stress appears to be a major constraint to plant and crop productivity. Hence,
our understanding of salinity impact on various aspects of plant metabolism and
its tolerance strategies. Crop productivity is severely affected by salinity
stress. This occurs directly due to the impact of photosynthesis, respiration,
nutrient assimilation, hormonal imbalances, etc.
Plant hormones, also known as phytohormones, are small chemical messengers
produced within the plant at extremely low concentrations and play a crucial
role in plant growth and development by coordinating cellular activities. It
controls all aspects of plant growth and development, from embryogenesis to
regulation of organ size, pathogen defense, stress tolerance, and reproductive
development. Unlike in animals (in which hormone production is restricted to
specialized glands), each plant cell is capable of producing hormones.
Phytohormones occur across the plant kingdom, including algae, where they
perform functions similar to those in higher plants. Some phytohormones also
occur in microorganisms, such as unicellular fungi and bacteria; however, in
these cases they do not play a hormonal role and are better regarded as
secondary metabolites. Auxin plays an important role in cell elongation in the
shoot, apical dominance, root initiation, prevention of abscission, induction
of parthenocarpy, stimulation of respiration, activation of cell division, and
induction of callus formation, and induction of vascular differentiation in
plants. NAA is a synthetic plant hormone in the auxin family and is an integral
component in many commercial plants rooting horticultural products. It is a
rooting agent and is used for the vegetative propagation of plants from stem
and leaf cuttings. It is also used for plant tissue culture. Kinetin is a
cytokinin derivative that promotes cell division and plant growth. It has been
shown to naturally occur in the DNA of organisms, including humans and various
plants. While kinetin is used in tissue cultures to produce new plants, it is
also found in cosmetic products as an anti-aging agent. Gibberellic acid, a
plant hormone stimulating plant growth and development, is a tetracyclic
di-terpenoid compound. GAs stimulate seed germination, trigger transitions from
meristem to shoot growth, juvenile to adult leaf stage, vegetative to
flowering, determine sex expression and grain development along with an
interaction of different environmental factors viz., light, temperature, and
water (Sivakumar et al.,2018).
