Abstract
A survey of 31 grasses and sedges belonging to familiesPoaceae and Cyperaceae growing around. Faisalabad was carried out to deteime their photosynthetic pathway, Various characters studied. were anatomy, distribution of starch in various tissues of leaves, vein frequency and CO2 compensation point. All the characteris-tics studied showed that among all the species investigated only Triticum aestivum, and Oryza sat iva were found to possess 0-3 pathway while all clans had C-4 pathway of photosynthesis.
INTRODUCTION
The major pathway of CO2 fixation in_ plants is 0-3 or Calvin cycle which is characterized by its initial 3-0 product, phoThoglyceric acid. Kortschak et al. (1965) reported that first product of photosynthesis in sugar cane Was a 0-4 organic acid (Oxaloaceticacid) and not phosphoglyceric acid. This observa-tion was later confirmed and elaborotecl by Hatch and Slack (1966) in the form of a noval 0.4 pathway. Various physiological, anatomical and biochemical characteristics were correlated viiith C-4 pathway (Smith and Brown, 1973; Ha-ttersIey and Watson, 1976.) The signicance of C-4 pai h sky his in its mere efficicnt mcchanicm of CO2 fixaticn as c( irrarcd to C-3 ratliwEly. asErvations have made it evident that a syndrome of anatomical and physiological characteristics rela-ting to high efficiency 002 fixation called Kranz syndrome occur in plants of tropical origin (Smith anp Brown, 1973; HattersIey and Watson, 1976), Vari-ous charcteristies of C.4 plants which may be used to distinguish them from 0-3 type of plants have been reported in this study.
MATERIALS AND METHODS
Grasses for this study were collected from NIAB field on a sunny day and in the afternoon. The list of the examined species is as follows
* Deparment of Botany, University of Agriculture, Faisalabad. ** Soil Biology Division, Nuclear Instiute for Agriculture and Biology (NIAB), Faisalabad.
