Photosynthesis in different mulberry cultivars

Abstract

The leaf architecture, net photosynthetic rate, 14CO2 fixation pattern and chlorophyll content were studied in mulberry cultivars. Light microscopic studies exhibited various characteristics of leaf architecture such as the stomatal number, cuticle thickness, length of palisade cells, and interveinal distance among the local mulberry cultivars Kanva- 2, Mysore local and S41. Kanva-2 was superior among the studied cultivars because it had the highest photosynthetic 14CO2 fixation rate. The short- term products of carbon fixation studied by radiotracer techniques, autoradiography and chromatography showed that the amino acids and sugar phosphates were predominantly synthesised in comparison with organic acids and sugars in all three cultivars. Kanva-2 also showed the highest incorporation of 14CO2 in amino acid fraction (41%) as compared to Mysore local (34 %) and S41 (28 %). The dominant synthesised amino acids included glycine, serine and alanine. One hour 14CO2 fixation products were also different among the cultivars: Kanva-2 showed maximum incorporation in sucrose. Hence Kanva-2 had efficient mechanism of carbon fixation and utilization for synthesis of sucrose.