Apr 2, 2021
1. What is “bio-stimulant”?
“Containing substances and/or micro-organisms whose function when applied to plants or the rhizosphere is to stimulate natural processes to enhance/benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress, and crop quality.”
It’s important to note that biostimulants act only a plant’s vigor, offering no direct action against diseases, insects, or weeds. And bio-stimulants are not Plant Growth Regulators, which are a different class.
2. The main advantages of standard yeast extract in biostimulant application
- Improve quality and increase yield: small molecule oligopeptides inside of yeast extract can be directly absorbed by crops, reducing the pressure of metabolic synthesis in the early stage of crop growth, promoting chlorophyll synthesis, enhancing photosynthetic efficiency, and accumulating photosynthetic products; at the same time, glucan and mannose oligomers derived from yeast cell walls can promote the absorption and transportation of trace elements such as calcium and magnesium, and achieve the effect of improving crop quality and increasing production.
- Activating the soil: The amino acids, nucleotides, B vitamins, etc. rich in yeast extract can quickly promote the reproduction and growth of soil microorganisms, and activate soil nutrients.
- Promoting growth and resistance: degradation substances from yeast nucleic acid such as purines, pyrimidines and other natural endogenous growth factors can significantly promote cell division and stimulate root elongation; the synergistic effect of amino acids and trehalose can improve plants to overcome abiotic stresses (such as frost, oxygen deficiency of root, salinity, drought, etc.).
Fig.1. Appearance of standard yeast extract
Fig.2. Water solution of standard yeast extract
Parameters of standard yeast extract
Free amino acid（%）
3. The performance of standard yeast extract
Fig.3. Root-promoting experiment on cabbage
It can be seen from Fig. 3 that the use of coconut peat + humus soil substrate for cabbage cultivation and root irrigation treatment with 10ppm yeast peptide can significantly promote the growth of cabbage root system, and the root system is more developed.
Fig.4. Root-promoting experiment on garlic
It can be seen from Fig. 4 that if using hydrolytical cultivation method with total nutrient for cultivating garlic, the additional treatment of 1ppm and 10ppm of standard yeast extract respectively can significantly promote the growth of garlic roots. According to statistics, compared with the control, 1ppm treatment increased the average root number of garlic by 19.5%, root length by 11.2%, leaf length by 9.1%, and leaf fresh weight by 11%.
Fig. 5. Growth promotion experiment on corn
It can be seen from Fig. 5 that spraying with 1g/15L and 5g/15L yeast extract can significantly promote the growth of corn, and the plants are taller; spraying with 10g/15L, 15g/15L and 20g/15L yeast extract, the plant height is similar to that of the control (plants in the rightmost column), but with more emerald green leaves. Experiments show that yeast extract has a strong effect of stimulating crop growth at low concentrations; at high concentrations, the biological stimulation function of yeast extract is weakened and the function of plant nutrition is changed.
Fig.6. Drought resistance experiment on pepper seedlings
It can be seen from Fig. 6 that the peppers withered after 5 days of complete drought stress (CK); the water treatment group was sprayed once, and the pepper seedlings were dehydrated and wilted after 5 days; sprayed with 1ppm standard yeast extract, the petioles and leaves of the peppers remained tall and straight and show drought resistance; sprayed with high-concentration yeast extract, additional nutrients were provided to crops and leaves further growth as well as showing drought resistance.