Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

Functional variations in efficiency of PSII during the ontogeny of leaf in Saraca asoca- a tropical plant species

Shasmita . , Barsha Swain, Smrutirekha Mishra, Debasish Mohapatra, Soumendra Naik, Pradipta Mohapatra

Abstract

The tropical evergreen tree species’ leaf ontogeny is extended into months with changes in size, shape, coloration and internal tissue distribution. The Saraca asoca (Roxb.) Willd. tree leaf initiation generally occurs once in a year during February-April followed by very limited leafing thereafter. We measured the rate of photosynthesis, chlorophyll a fluorescence, energy quenching, and photosystem II (PS II) functions during leaf ontogeny process. The observations were taken up to 35 days after opening of lamina (DAOL). Significant increase in the synthesis and accumulation of photosynthetic pigments but negative net photosynthesis was noticed during initial days of the ontogeny. The leaf moved from heterotrophy to autotrophy with gradual improvement of PS II functions. The Ci/Ca ratio showed significant change at ≥ 11 DAOL. Increase in the age of the leaf (between 5-28 DAOL) caused decrease in O-J rise and corresponding increase in J-I and I-P rise as well as of fluorescence maximum (FM). The improvement of the electron transport components of the donor side of PS II was seen with increase in the functional oxygen evolving complex. The functional improvements of the donor and acceptor side of PS II during leaf ontogeny are discussed.

FP24176  Accepted 03 September 2024

© CSIRO 2024