Plastids of sieve tube members in the stamen vascular bundle ofSorghum bicolor (Gramineae)

On the Occurrence of P-type Plastids in Sieve Elements of Sugarcane Short Communication

“…Plastids of the monocotyledon species have been characterized as P-type which contain proteinaceous inclusions and frequently starch grains (Behnke 1971c). However, species belonging to the grass family are devoid of starch and their sieve element plastids contain only proteinaceous inclusions (Behnke 1972, Singh and Srivastava 1972, Laser 1974). According to a recent report (Behnke 1975) some 270 species of seed plants have been described to contain P-type plastids in their sieve elements.…”

“…Smaller inclusions probably represent early forms in their growth. The plastid inclusions in sugarcane sieve elements have the characteristic features of those regarded as cuneate proteinaceous crystalloids (Behnke 1972, Singh and Srivastava 1972, Laser 1974. Plastids are totally devoid of starch (Figs.…”

“…1, 2). The sieve element plastids in sugarcane, thus, can be classified as P-type, a characteristic feature of the sieve elements in monocotyledon species (Behnke 1969, 1971c, 1972, 1973, 1975, Singh and Srivastava 1972, Laser 1974.…”