In order to have better knowledge of African sages, we begun the study of some Salvia species (Serrato Valenti, 1997; Bisio et al., 1998; Bisio et al., 2001) belonging to the G species-group according to Hedge classification (1974). In the present work we examined the ultrastructure and the histochemistry of the glandular trichomes, and the essential oil and the exudate products of Salvia dolomitica Codd., a shrub, native of Transvaal, South Africa. The leaves of S. dolomitica appeared covered by uniseriate non-glandular trichomes and glandular trichomes. The latter occurred as peltate and capitate (Bisio et al., 2001). The histochemistry of peltate hairs evidenced a secretion with abundant hydrophobic substances, but also small quantities of hydrophilic substances (polysaccharides, flavonoids, phenols, essential oil, triterpenoids). The ultrastructural observations are consistent with the histochemical ones; indeed, the former showed abundant plastids and smooth endoplasmic reticulum (SER), typical organelles of lipophilic secreting cells, as observed in many other trichomes secreting lipophilic substances. SER can also be responsible for flavonoid secretion, as indicated also by Schopker et al. (1995). Two types of capitate hairs, depending on the number of the secreting and stalk cells, were observed. The cytoplasm of type I presented numerous Golgi stacks, plastids and dilated ER, that are organelles respectively responsible for secretion of polysaccharides, terpenes and also flavonoids. Indeed, histochemical observations indicated a complex secretion, in which phenolic compounds, polysaccharides and terpenes were present. Also in type II trichomes the histochemical and ultrastructural observations indicated a complex secretion with phenolic compounds, polysaccharides and terpenes, but probably the release of secretion occurs in a different way and at a different time. In S. dolomitica the essential oil was mainly constituted by monoterpene hydrocarbons, followed by oxigenated monoterpenes and sesquiterpene hydrocarbons. The main components of the oil were represented by substances that are often described for other Salvia species, 1,8-cyneol, limonene, -3-carene, -pinene and -caryophyllene. The analysis of leaf surface extract identified abietane diterpenoids: carnosol and 7-methoxirosmanol suggesting that these products could be good taxonomic markers. BISIO A, FONTANA N, ROMUSSI G, DE TOMMASI N. 1998. Pharmazie 53: 210-211. BISIO A, ROMUSSI G, MALECI L, CORALLO A, ZAPPA E, PROFUMO P. 2001. 96°Congresso della Società Botanica Italiana – Varese 26-28 settembre 2001. 145. HEDGE IC. 1974. Notes from the Royal Botanic Garden, Edinburgh. 33: 1-118. SCHÖPKER H, KNEISEL M, BEERHUES L, ROBENEK H, WIERMANN R. 1995. Planta 196: 712-719. SERRATO-VALENTI G, BISIO A, CORNARA L, CIARALLO G. 1997. Annals of Botany 79: 329-336.
Advance in histochemistry, ultrastructure and secretion of glandular trichomes in Salvia dolomitica Codd.
BISIO, ANGELA;ROMUSSI, GIOVANNI;
2004-01-01
Abstract
In order to have better knowledge of African sages, we begun the study of some Salvia species (Serrato Valenti, 1997; Bisio et al., 1998; Bisio et al., 2001) belonging to the G species-group according to Hedge classification (1974). In the present work we examined the ultrastructure and the histochemistry of the glandular trichomes, and the essential oil and the exudate products of Salvia dolomitica Codd., a shrub, native of Transvaal, South Africa. The leaves of S. dolomitica appeared covered by uniseriate non-glandular trichomes and glandular trichomes. The latter occurred as peltate and capitate (Bisio et al., 2001). The histochemistry of peltate hairs evidenced a secretion with abundant hydrophobic substances, but also small quantities of hydrophilic substances (polysaccharides, flavonoids, phenols, essential oil, triterpenoids). The ultrastructural observations are consistent with the histochemical ones; indeed, the former showed abundant plastids and smooth endoplasmic reticulum (SER), typical organelles of lipophilic secreting cells, as observed in many other trichomes secreting lipophilic substances. SER can also be responsible for flavonoid secretion, as indicated also by Schopker et al. (1995). Two types of capitate hairs, depending on the number of the secreting and stalk cells, were observed. The cytoplasm of type I presented numerous Golgi stacks, plastids and dilated ER, that are organelles respectively responsible for secretion of polysaccharides, terpenes and also flavonoids. Indeed, histochemical observations indicated a complex secretion, in which phenolic compounds, polysaccharides and terpenes were present. Also in type II trichomes the histochemical and ultrastructural observations indicated a complex secretion with phenolic compounds, polysaccharides and terpenes, but probably the release of secretion occurs in a different way and at a different time. In S. dolomitica the essential oil was mainly constituted by monoterpene hydrocarbons, followed by oxigenated monoterpenes and sesquiterpene hydrocarbons. The main components of the oil were represented by substances that are often described for other Salvia species, 1,8-cyneol, limonene, -3-carene, -pinene and -caryophyllene. The analysis of leaf surface extract identified abietane diterpenoids: carnosol and 7-methoxirosmanol suggesting that these products could be good taxonomic markers. BISIO A, FONTANA N, ROMUSSI G, DE TOMMASI N. 1998. Pharmazie 53: 210-211. BISIO A, ROMUSSI G, MALECI L, CORALLO A, ZAPPA E, PROFUMO P. 2001. 96°Congresso della Società Botanica Italiana – Varese 26-28 settembre 2001. 145. HEDGE IC. 1974. Notes from the Royal Botanic Garden, Edinburgh. 33: 1-118. SCHÖPKER H, KNEISEL M, BEERHUES L, ROBENEK H, WIERMANN R. 1995. Planta 196: 712-719. SERRATO-VALENTI G, BISIO A, CORNARA L, CIARALLO G. 1997. Annals of Botany 79: 329-336.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
