Discussion on the combination of Gibberellic acid and surfactants for fruit cracking prevention

 

Gibberellic acids (GAs) are a class of tetracyclic diterpenoid substances, which are used as a growth regulator treatment. The function of GAs is not only to promote plant growth, but also to induce phase transitions during development.

 

GAs can regulate seed dormancy. Some plant seeds are under the dormancy condition during purchasing. GA treatment would stimulate seed germination, and induce hydrolytic enzymes such as amylase and protease. The seeds treated by GA were left to germinate in a dark environment and under low temperature. According to plant physiology, GAs regulate plant development, especially for dwarf cultivars. When the light compensation point of plants is reduced, GA increases the light saturation point range, which improves the effects of light intensity on plant growth and leaf development. 

 

GA also influences the control of flowering time and sex expression. For example, spraying the growth regulator @500~1500ppm on the female cucumber plant can induce the male flower development. Spraying the treatment @10~100 ppm on violets or geraniums for substitute GA for long-day under the short-day condition. 

 

 

Fruit cracking is caused by plant physiological imbalance – the growth of the peel does not adapt to the growth of the fleshy tissue. Some research results showed that certain factors influenced fruit cracking: a) turgor pressure; b) elasticity of fruit skin; c) structure of fruit skin; d) growth rate.

 

The turgor pressure is influenced by the contents of water, GAs and abscisic acid. The elasticity level is influenced by the contents of Ca and the cell wall. The relaxed DNA of cells determines the structure of the fruit skin. When the factors are in an imbalanced condition, it can lead to cracking of fruits.

 

On the other hand, the rainy season can also cause fruit cracking because the water uptake increases the turgor pressure level. The growth rate of fleshy tissues (fresh) is faster than the fruit peel due to the drought damage during the dry season. But when it rains, plants absorb water and nutrition quickly. The development of sarcocarp (fresh) is imbalanced with the peel, increasing the turgor pressure level and causing fruit cracking. Growers often spray GA to balance the turgor pressure system.

 

 

The plant's waxy blade surface covers the vitro cutin membrane. The cutin membrane can lock water content in the tissue to anti-transpiration and regulate the water balance that protects chloroplast functions and maintains ion homeostasis. In general, the growers spray regulation treatment agents and mix surfactant adjuvants to improve the effects. PINEYE^® Emulsion has wetting and extending properties, it is an excellent choice of adjuvant to decrease the shear angle and increase the extension area to improve agrochemical efficacy.

 

But research results show that the surfactants may not improve the effects for GA and will increase the cost. GA also shows good efficacy when it is sprayed independently. So, we advise growers to spray adjuvants in a combined manner, according to the different plant growth stages.

 

PINEYE^® Emulsion is the nonionic sticker type adjuvant. The liquid sprayed on the surface of foliage and fruits will form the sticky coating. The natural coating can assist the fruit peel in regulating turgor pressure level with fleshy tissues (fresh) with a physical effect, such as the sealants. It is a different method compared to the plant physiology mechanism of regulation agents.

 

Especially during the fruit ripening stage, spray PINEYE^® Emulsion on fruits and leaves during the rainy season; the organic sticky coating can prevent rain from washing out the fungicides or regulator agents. The surfactant adjuvant effects a blocking performance to decrease the rain from putting pressure on the peel. The sticky residues also suture the cracked peel and prevent cracking from deteriorating. GAs regulators and PINEYE^® Emulsion complement each other and can be used in combination during different situations.

Benefits
 

♦  Forming a natural coating and preventing rain from washing out regulator agents that avoid re-spraying and agent cost

♦  Forming a sunscreen coating, providing defense against sunburn and UV damage on hot days, and preventing transpiration

♦  Balancing the turgor pressure system of fruits

♦  Keeping the fresh color after the regulators are treated on the fruits. Extending the fruit supply time

♦  Complementing each other when used with regulator agents 

REGULATORS	Seeds	Leaves	Fruits	Stem	Roots
Sprout	√	-	-	-	√
Seeding	√	√	-	√	√
Vegetaive	√	√	-	√	√
Budding	√	√	-	√	√
Flowering	√	√	-	√	√
Ripening	√	√	√	√	√

ADJUVANTS	Seeds	Leaves	Fruits	Stem	Roots
Sprout	×	-	-	-	×
Seeding	×	√	-	√	×
Vegetaive	×	√	-	√	×
Budding	×	√	-	√	×
Flowering	×	√	-	√	×
Ripening	×	√	√	√	×