Physiological and growth changes in micropropagated Citrus macrophylla explants due to salinity

Area of Science:

• Plant Science
• Agricultural Science
• Biotechnology

Background:

• Salinity is a major abiotic stress limiting crop productivity globally.
• Citrus macrophylla is an important crop susceptible to salt stress.
• In vitro culture offers a controlled environment to study plant stress responses.

Purpose of the Study:

• To evaluate the growth and physiological responses of Citrus macrophylla explants to salt-induced stress using in vitro culture.
• To determine the effects of varying NaCl concentrations on explant development and stress indicators.

Main Methods:

• Micropropagated adult Citrus macrophylla explants were cultured in media with different NaCl concentrations.
• Growth parameters, physiological indicators (MDA, chlorophyll), ion content (Na+, Cl-), and compatible solutes (proline, QAC) were analyzed.

Main Results:

• NaCl treatments significantly reduced growth parameters and induced visible salt injury.
• Malondialdehyde (MDA) increased, indicating membrane damage, and chlorophyll content decreased with rising salinity.
• Explants accumulated proline and quaternary ammonium compounds (QAC) for osmotic adjustment, correlated with Na+ and Cl- uptake, especially in proliferated shoots.

Conclusions:

• In vitro culture effectively demonstrated the negative impacts of salinity on Citrus macrophylla.
• Salt-induced damage in explants is primarily attributed to the toxic effects of saline ions, particularly chloride, at the cellular level.
• The study highlights the potential of in vitro systems for assessing salt tolerance in Citrus species.