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plant growth and physiology and improved
crop yields. In floricultural crops, application
of biostimulants therefore results in faster
maturity, longer stem lengths, bigger flower
head (bud) sizes, improved plant health and
longer postharvest life of cut flowers.
Basically, plant biostimulants are
foliar applied or drenched
into the growing media. It
is important to understand
the possible mechanisms
by which these products
Foliar applied biostimulants also reduce
transpiration, enhance stomatal conductance
and up-regulate stress resistance metabolism
leading to enhanced photosynthesis, tolerance
to salt, drought and extreme temperatures.
Plant biostimulants also enhance nutritional
quality of the crop by altering metabolism and
up-regulation of the bio-synthetic enzymes.
Drenched biostimulants promote plant
growth rhizobacteria, improve nodulation of
certain crops, suppress soil borne pests and
pathogens and induce abiotic stress tolerance
by modulation of root exudates, enhancing
growth-friendly microbes, altering metabolism
and root architecture, differential expression
of signal molecules and bio-synthetic enzymes
and promoting efficient water and nutrient
uptake.
Amino acid-based biostimulant products
directly play a vital role in nitrogen and
carbon metabolism, and the resistance of
plants to abiotic and biotic stress. Amino
acids contained in this group of biostimulants
provide ready-made building blocks for
synthesis of protein, which plants need for
structural, metabolic (enzymes) and transport
functions.
effect growth and physiological responses in
plants. Foliar applied biostimulants modulate
the phytochromes, increase photosynthetic
efficiency and carbon assimilation and delay
senescence resulting in improved shoot and
root growth, increased flowering and better
yield.
Some of the biostimulant products have
anti-microbial, antifeedant, insect repellent
or disease resistance gene up-regulation
properties hence induce biotic stress resistance
and/or tolerance when sprayed on plant
foliage.
For instance, glycine and glutamic acids
commonly found in amino acid-based
biostimulants are fundamental metabolites
in the formation of vegetative tissues and
chlorophyll synthesis leading to higher degree
of photosynthesis and generally greener plants.
When applied together with micronutrients,
these amino acids promote the absorption and
transportation of the micronutrients inside
the plant due to their chelating effect.
Furthermore amino acids are precursors or
activators of phytohormones and growth
substances such as ethylene, auxin an