Assertion(A) : ATP formation is not accompanied by NADP reduction and oxygen liberation in stroma lamellae.

Reason (R) : Stroma lamellae membranes lack PSII and NADP reductase enzyme

Assertion is true. In the stroma lamellae of the chloroplast, ATP is formed through the process of cyclic photophosphorylation, which does not involve the production of NADPH or the release of oxygen. Instead, it relies on the electron transport chain to generate a proton gradient across the thylakoid membrane, which is then used by ATP synthase to produce ATP.

Reason is true. Stroma lamellae membranes lack PSII, which is responsible for the production of NADPH and oxygen during non-cyclic photophosphorylation, they do contain PSI and the enzyme ferredoxin-NADP+ reductase, which can reduce NADP+ to NADPH when the electron carrier ferredoxin is reduced.

Both A and R are true and R is the correct explanation of A. ATP formation in stroma lamellae is not directly accompanied by NADP reduction and oxygen liberation.