Mulberry genotypes were subjected to salinity (0-12 mS cm-1) in pot culture experiment. Chlorophyll and total carotenoid contents were reduced considerably by salinity. At low salinity, photosynthetic CO2 uptake increased over the control, but it decreased at higher salinity. Contents of soluble proteins, free amino acids, soluble sugars, sucrose, starch, and phenols increased at salinity of 1-2 mS cm-1 and decreased at higher salinity (8-12 mS cm-1). Glycine betaine accumulated more than proline, the maximum accumulation of both was at salinity of 2-4 mS cm-1. Among the genotypes studied, BC2-59 followed by S-30 showed better salinity tolerance than M-5. and P. Agastian, S. J. Kingsley, M. Vivekanandan.
We present here our adventures in research in photosynthesis with George C. Papageorgiou (1933-2020) focusing on George's initiative in the discovery of the protective effects of glycine betaine on the oxygen-evolving photosystem II complex. We end with a brief description of research on glycine betaine-synthesizing transgenic cyanobacteria. Two of us, Norio Murata (in Japan) and Kostas Stamatakis (in Greece), and all our collaborators, have the highest respect for George, and we miss him and our intense discussions with him on various topics of photosynthesis research.