Micromorphology and ultrastructure of trichomes of Libyan Salvia fruticosa Mill.

Abstract

Micromorphological and ultrastructural analyses of the leaf trichomes of Salvia fruticosa Mill. were performed by light and electron microscopy. The leaves bear numerous non-glandular unbranched trichomes, and peltate, capitate and digitiform glandular trichomes. Very elongated flagelliform non-glandular trichomes densely covered the leaf surfaces, with especially abundance on the leaf margins. Peltate trichomes consist of a basal epidermal cell, a very short stalk cell and a large round head of eight secretory cells arranged in a circle. Capitate trichomes can be divided into two main types, short-stalked and long-stalked, and further into five subtypes according to the number of stalk cells, morphology and number of glandular head cells. Digitiform trichomes consist of one basal cell, one or two stalk cells and one apical secretory cell, which are of similar diameter and approximately equal length. [Projekat Ministarstva nauke Republike Srbije, br. 173029 i br. 173015

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“…Three types of glandular hairs have been found in S. triloba, peltate, capitate and finger shaped trichomes (digitiform). Peltate trichome consists of a basal cell, a short unicellular stalk, and a large secretory head with 8 secretory cells, the same is reported for S. fruticosa Mill, in the Libyan region which consists of a basal cell, a unicellular stalk, and a large head composed of eight secretory cells arranged in a circle [12] (Fig. 2/1).…”

Micromorphology and histochemistry of leaf trichomes of Salvia aegyptiaca (Lamiaceae)

“…Peltate trichomes are usually composed of a basal epidermal cell, a short wide stalk cell and a large round head of several secretory cells, which could vary in number among Salvia species, from four cells in S. blepharophylla [56], S. divinorum [23] and S. verticillata [57] to six or eight cells in a single disc in S. aurea [20], S. officinalis [51], or by 12-18 cells arranged in two concentric circles with four central and eight or more peripheral cells [13,21,25,58,59]. The present study showed that S. aegyptiaca has peltate glandular trichomes consisting of the basal epidermal cell, short cylindrical stalk cell with cutinized lateral walls and large round head of eight secretory cells arranged in a circle, as observed in the previously studied S. fruticosa from Libya [28]. During the secretion phase, peltate trichomes have a characteristic spherically shaped or slightly flattened head due to the development of a large subcuticular space where secretory products accumulate [55,60].…”

“…Plant species that develop glandular trichomes generally produce relatively large amounts of bioactive compounds that include highly concentrated phytochemicals possessing biological activity and potential applications in the food or pharmaceutical industries [15][16][17][18][19]. There are a number of studies on the foliar micromorphology of representatives of the genus Salvia [3,[20][21][22][23][24][25][26][27][28]. Tissier [29] emphasized that plant glandular trichomes represent a broad area of research, mainly due to interests in elucidating the biosynthetic pathways of industrially relevant compounds, such as essential oils, pharmaceutical ingredients or substances, which may be used in plant defense.…”

Morphology, Anatomy and Chemical Composition of Salvia fruticosa Mill in Al-Marj (Libya)

“…It is distributed from Italy and Cyrenaica through the South Balkan Peninsula to West Syria [25] . Libyan S. fruticosa, valued for medicinal and culinary properties due to essential oils produced in glandular trichomes, has been studied from micromorphological and ultrastructural points of view [26] .…”