floriNEWS Magazine.pdf Jul. 2014 | Page 7

5 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