Role of Abscisic Acid under Water Deficit Stress in Plants | Chapter 4 | Contemporary Research and Perspectives in Biological Science Vol. 10

Abscisic Acid (ABA) and water deficit stress are interlinked to each other. A deficit of water induces the synthesis of ABA for an increase of osmoprotectants, antioxidants and membrane stability as well as a decrease in water loss. The phytohormone that induces the factor for the protection of plant under stress is known as an antistress phytohormone and Abscisic acid (ABA) is a well-known antistress phytohormone that saves the plant from adverse water deficit stress in cells. Its concentration increases when plants sense water deficit stress and its signal transduction pathway activates leading to cellular responses to activate the genes. It stimulates stomatal closure, change in gene expression and adaptive morpho-physiological responses. Light regulates stomata opening and ABA promotes partial or complete closure of stomata. The closure of stomata reduces the loss of water by transpiration which accounts for approximately 90% through its pore. At the same time, complete stomatal closure prevents the exchange of gases through its pore resulting in the decrease of the Calvin cycle and eventually reduction of biomass. Moreover, the efflux of water decreases and influx increases in the cell due to the synthesis of water-capturing compatible solutes viz. proline, glycine betaine, sugars (sucrose, fructose, trehalose), polyols (sorbitol, mannitol, arabinitol, glycerol), etc. which are induced by ABA. However, proline and glycine betaine are prominent among all these compatible solutes. Thus, ABA regulates the factors that help the plant cope up the water deficit stress. Proline biosynthesis in chloroplasts reached up to 80% during stress as compared to 5% in normal which facilitates the electron flow between photosynthetic excitation centers and maintains a low NADPH:NADP ratio in cells.

 

Author (s) Details

 

Kamal Kant
Aspee Shakilam Biotechnology Institute, Navsari Agricultural University, Surat,India.

 

Please see the book here:- https://doi.org/10.9734/bpi/crpbs/v10/4263

Toward Elicitation of Bioactive Secondary Compounds with Environmentally Sound Plant Treatments: Insight into the Balance between Photosynthetic Primary and Kaempferol Accumulating Secondary Metabolism Using Young Soybean Plants | Chapter 2 | Cutting-edge Research in Agricultural Sciences Vol. 10

 There are few environmentally friendly plant treatments that can impose mild physiological stress and induce bioaccumulation of useful phytochemicals like kaempferols. In young greenhouse-grown soy plants, we tested ABA foliar application at 100 or 200 M, as well as two types of leaf wounding, piercing or hole punching. The same leaf was used to measure gas exchange and A/Ci response, PSII, pigments, and antiradical activity, while the leaf above was used to measure kaempferols. When compared to the control, ABA 200 M-treated plants had 20% less gas exchange and 17% less ETR, but higher Vcmax and Jmax. They had 55% and 100% more stomatal limitation to Pnet and PSII, respectively. in comparison to the control Leaf-wounded plants exhibited the least stomatal limitation to Pnet or PSII. When compared to the control, leaf piercing increased chlorophylls by 39% and carotenoids by 38%. Six kaempferols were identified as mono-, di-, and triglycosides. When compared to the control, each leaf treatment increased total kaempferol yield by 42 percent in the ABA 100 M treatment and 68 percent in the ABA 200 M treatment. In general, kaempferol yields in ABA 100 M were positively correlated with Pnet. Pnet in leaf-pierced plants was negatively correlated with gs in ABA 200 M-treated plants and positively correlated with gs in ABA 200 M-treated plants. The findings of this study show that environmentally friendly foliar treatments can significantly increase kaempferol yield and thus phytochemical or nutritional quality of soy leaves. ABA application and wounding had different effects on the relationship between photosynthetic primary metabolism and kaempferol accumulation. ABA application and wounding are both promising leaf treatments for increasing kaempferol levels in young soy leaves.

Author (S) Details

H. H. Ratnayaka
Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA-70125, US.

S. Boue
USDA-ARS, Southern Regional Research Center, 1100 Robert E. Lee Boulevard, New Orleans, LA 70124, US.

T. Dinh
Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA-70125, US.

S. B. Le
Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA-70125, US.

R. Cherubin
Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA-70125, US.

View Book :-  https://stm.bookpi.org/CRAS-V10/article/view/1559