CHAPTER - VIII EPIDERMIS 114
8.1. INTRODUCTION Plant epidermis is broadly recognized into 3 components viz. 1) The epidermal cell complex 2) Stomatal complex 3) Trichome complex. Although we have considerable knowledge with reference to the above information in general ( Prabhakar et. al., 1975, 1979, 1980, 1984; Van cottehem, 1970; Upholf, 1962; Dilcher, 1974; Prabhakar and Leelavathi, 1989). But very meager information is available with reference to the individual families of different angiospersms (Solereder, 1908; Metcalfe and Chalk, 1950). Hence the present study has been taken up which gives a detailed investigation on structure, nature distribution and taxonomic significance of foliar epidermal cell complex, stomatal complex and trichome complex of important taxa from the identified plants 8.2. MATERIALS AND METHODS The following methods were adopted in order to investigate some medicinally important plants used by Gondu tribal people. The five (5) plants are selected for their leaf epidermal studies from 45 plants investigated were collected personally by the author. Fixation of the Material: Mature plant parts (leaves) were fixed in the Carney s fixative consisting of alcohol and glacial acetic acid 3:1 (Johanson, 1940). After two days the fixative was replaced by 70% alcohol for preservation of the material. Details of micro-techniques employed and their importance in the present study are as follows: I) Micropreparations: This consists of (1) entire mounts as well as (2) sections of concerned plant parts. a) Epidermal peelings: The bulk of the data on epidermis presented in this work is chiefly based upon these micro-preparations of either surfaces of the leaf. The 115
preparations are of particular significance in obtaining a comprehensive picture of the surface view of the leaf epidermis. Several techniques were employed in the preparation of the epidermal peels. In the case of larger leaves which easily yield peels, the later come off by mere scraping with a blade or by inserting a sharp needle below the epidermis and pulling it out. In the case of material too hard to yield peels several techniques were attempted such as double treatment method (Leelavathi, 1976) and TAT method which gave satisfactory results. The peels were prepared from base to apex, midvein to margins and laminal area of the leaf. b) Isolated Trichomes: In plant parts which are highly tomentose, it is rather difficult to follow the morphology of the individual trichomes. Study of isolated trichomes is essential as this facilitates in examining them from varied directions. Trichomes were isolated by scraping the plant part with a scalpel or blade or by crushing the young apices as such or after treating them with dilute hydro-chloric acid. The varied types of micropreparations described were stained with aniline blue and Toludine blue and mounted in glycerine. Afterwards they were dried on slide warmer or in a desiccators, the cover glass was ringed with Canada balsam or D. P. X. mountant. II) Sections: These are essential besides the whole mounts, in order to examine the position of guard cells and ledges, shape and position of the foot of trichomes. Preparations of both hand and microtome sections were used depending upon the requirements. a) Hand sections: This method has been found highly desirable wherever the trichomes are quite robust, long and sclerified. The sections thus obtained were stained with aniline blue in lactophenol and prepared into slides as described above. 116
b) Microtome sections: These are required in studying particularly to examine the guard cells and ledges, shape and positions of the foot of trichomes. Permanent Canada balsam mounts were prepared following the usual paraffin method (Johanson, 1940). Several stain combinations were used viz., Ehrlich s hematoxylin or crystal violet with basic fuchsin as counter stain were useful. III) Micrometry: Epidermal cell frequency (E. C. F), stomatal frequency (S.F), Stomatal Index (S.I) were calculated at 5 places on both adaxial and abaxial surfaces. For calculating the epidermal cell frequency, the epidermal cells as well as stomatal subsidiaries were counted together. Costal cells were excluded for the purpose of calculating E. C. F. of the peels. The values are averages derived usually from ten readings. Stomatal indices (S.I) at individual five location on each plant were calculated following the Salisbury (1927) as given below: Stomatal Index: No. of Stomata X 100 No. of stomata + No. of epidermal cells TERMINOLOGY Plant epidermis is distinguished into three components 1. Epidermal cells 2. Stomata and 3. Trichomes (Esau, 1972). Later Rajgopal (1973), in view of their heterogeneous characters, showed the necessity of designating them as (i) Epidermal cell complex, (ii) Stomatal complex and (iii) Trichome complex which is adopted here. The definitions of the different technical terms 117
presently used in describing the characters of these complexes and other characters are as follows: i) EPIDERMAL CELL COMPLEX Respresents the epidermal elements other than those of trichome and stomatal complexes (Prabhakar, 1978). It is distinguished into the following three elements. Epidermal cells: Cells lying all over the lamina excluding those distinguished as Costal cells (Leelavathi, et al., 1976). Costal cells: Epidermal cells present on veins, which are usually distinct from other laminar epidermal cells (Leelavathi, et al., 1981b). Dermotype: Entries complement of epidermal characters of a plant (Prat, 1948) Side(s): Anticlinal walls of cell elements of the epidermis. They may be straight, curved, curved to wavy, wavy to sinuate and sinuses U or V shaped (Prabhakar et al. 1983) Shape: Shapes of the epidermal cells are recognized into the following: Polygonal: Cells having more than four sides: they could be isodiametric, anisodiametric and linear (cells in which the longest diameter is more than about twice the smallest diameter) (Prabhakar et al., 1983) Rectangular: Cells rectangular in shape (Prabhakar et al., 1983) Squarish: Four sided, more or less square in shape (Prabhakar et al., 1983) Trapezoidal: Cells trapezium-like, with two sides being parallel (Prabhakar et al., 1983) 118
Triangular: Cells with three sides, they may be linear acute obtuse shape (Prabhakar et al., 1983). Surface: Surface of cell wall is often characterized by several kinds of markings which may be seen in any epidermal cell. In the present study, the following terms have been used in their description. Smooth: Surface without any markings (Prabhakar et al., 1983: Tuberculate: With elevations slightly longer than broad and with round apex (Prabhakar et al., 1983: Pustulate: With elevations broader than long and obtuse apex. Orientaion: Denotes the direction in which the epidermal cell elements occur with reference to the axis of the plant part to which they belong: they may be parallels. Oblique or variously oriented (Prabhakar et al., 1983) Arrangement: Represents the organization of the epidermal cell elements to one another and with reference to the axis of the concerned plant part. They may be arranged irregularly, in vertical or transverse rows (Prabhakar et al., 1983) Perfect costal cell distribution: Characterised by costal cell expression over the entire venation system (including those forming the alveoli (Leelavathi et al., 1981 b) Imperfect costal cell distribution: Charaterised by total lack of costal cells, or expresssion of it only on midvein and lateral vein or only lateral veins (Leelavathi et al., 1981 b) Lamina: Leaf-blade excluding the petiole Adaxial: Adaxial surface of leaf-lamina Abaxial: Abaxial surface of leaf-lamina 119
(ii) STOMATAL COMPLEX Represents stomatal pore, guard cells and subsidiaries. Stoma: Apparatus consisting of a pair of guard cells enclosing a stomatal pore (De Bary, 1884) Subsidiaries cells: Cells surrounding a stoma in one or more cycles subsidiaries of the cycle abutting the stoma may be distinct from the adjacent epidermal cells, but of the other cycles (if present) distinct (Ramayya and Rajagopal, 1980) Cycles: Denote rings of subsidiaries: the ring of subsidiaries abutting the guard cells, called as the abutting cycle (Rajagopal, 1973) Monocyclic: Stoma surrounded by only one cycle of subsidiaries (Rajagopal, 1973). Subsidiaries regarding their spatial relationship with the subsidiaries of the other stomata are distinguished into the following three types (Rajagopal, 1973) a-type: When a subsidiary does not abute either a subsidiaries of another stomata f-type: When a subsidiary does not abut either a subsidiary of guard cell of another stomata Anisotricytic: Stoma with three distinct or indistinct subsidiaries forming conjoint walls and of which one distinctly larger and variable in position. (Leelavathi, 1976) Isotricytic: Stoma with three distinct or indistinct subsidiaries forming conjoint walls, nearly of equal size and variable in positon. Diacytic: Stoma with two distinct, or indistinct subsidiaries at poles, with conjoint walls at right angle to guard cells. 120
Tetracytic: Stoma with four distinct or indistinct subsidiaries, two polar, two lateral forming conjoint walls. Hypostomatic: Stomata are confined to only abaxial surface of the leaf (Esau, 1972) Amphistomatic: Stomata are borne on both the surfaces of leaf (Esau, 1972) (iii) TRICHOME COMPLEX Represents epidermal out growths. Foot: Part of the trichome lying in the epidermis (Ramayya, 1962 a) Trichome subsidiaries: The rosette of epidermal cells which surrounded the foot of the trichome. They may be distinct or indistinct. Body: Part of the trichome lying above the foot: when the body is differentiated, it is recognized into the following: a) Stalk: Proximal part of the body appearing distinct from the head portion (Ramayya, 1962 a) b) Head: Distal part of the body appearing distinct from the stalk (Ramayya, 1962 a) Trichiferous: Surface characterized by the presence of trichomes Amphitrichiferous: Trichomes confined to both surfaces. 121
8.3. OBSERVATINS AND DISCUSSIONS 8.3.1. EPIDERMAL CELL COMPLEX Introduction The epidermal cell complex forms the bulk of the epidermis, which is further distinguished into (1) epidermal cells, (2) Costal cells (3) Special epidermal cells. Epidermal cells are those which are confined to the inter costal areas and costal cells are those overlying the veins and are structurally distinct from the other epidermal cells while the special epidermal cells which are intermixed with costal cells or epidermal cells and are often distinctive due to their conspicuous shape, size and contents like varied types of crystals, mucilage, tannins etc., These cells are usually considered as idioblastic cells. A. Epidermal Cells Shape of Epidermal cells: The shape of epidermal cells of the presently studied taxa are different in different taxas. In Datura metal, they are rectangular non-linear on both adaxial and abaxial surfaces, polygonal anisodiametric linear on both the surfaces in Celestrus emarginata, while in Euphorbia hirta, the shape of the cells are squarish on adaxial surface but rectangular non-linear on abaxial surface, polygonal isodiametric on both adaxial and abaxial surfaces in Zizyphus jujube and in Holoptelea integrifolia the shape of the epidermal cells are polygonal anisodiametric non-linear on adaxial surface and rectangular linear on adaxial surfaces. The outer wall is flat in all the studied taxa on both the surfaces (Table- 3) (Plate-1, a-f) (Plate-2,g- j). Cytoplasm: The cytoplasm of the epidermal cells on both the adaxial and abaxial surfaces is mostly dense in all the studied taxa of Datura metal, Celestrus emarginata and Zizyphus 122
jujube except in Holoptelea integrifolia, the cytoplasm is scanty and translucent in Euphorbia hirta (Table - 4) (Plate-1, a-f) (Plate-2,g- j). Surface : The surface of the epidermal cells on both the adaxial and abaxial surfaces is smooth in all the studied taxa of Datura metal, Celestrus emarginata, Zizyphus jujube and Holoptelea integrifolia except in Euphorbia hirta, the surface is granulate in nature (Table - 4). Anticlinal Walls: Anticlinal walls of foliar epidermal cells are mostly straight in all the studied taxa of Celestrus emarginata, Zizyphus jujube and Holoptelea integrifolia on both adaxial and abaxial surfaces but with some exceptions that in Datura metal the anticlinal walls are curved on both adaxial and abaxial surfaces. In Euphorbia hirta the walls are sinuate on both the surfaces (Table - 5) (Plate-1, a-f) (Plate-2,g- j). Arrangement and Orientation: The cells of leaf epidermis are irregularly arrange and variously oriented on both the adaxial and abaxial surfaces in all the studied taxa of Datura metal, Celestrus emarginata, Euphorbia hirta, Holoptelea integrifolia and Zizyphus jujube (Table - 5). Epidermal Frequency: The frequency of epidermal cells differ on both the surfaces and also within the same surface and at various locations of the same leaf i.e., at leaf base, Midrib, Apex, Lamina and Leaf Margin. In Datura metal, on adaxial surface the maximum epidermal frequency is observed at leaf base as 94962.29 cm -2 and minimum is observed at leaf lamina as 12459.01 cm -2, on abaxial surface it is maximum at leaf midrib as 9426.29 cm - 2 and minimum at leaf margin as 50819.67 cm -2. Whereas in Celestrus emarginata, on adaxial surface the maximum epidermal frequency is observed at leaf base as 10918.03 cm -2 and minimum is observed at leaf lamina as 9426.29 cm -2, on abaxial surface it is maximum at leaf base as 11008.19 cm -2 and minimum at leaf midrib as 9385.24 cm -2. In Euphorbia hirta, 123
on adaxial surface the maximum epidermal frequency is observed at leaf midrib as 6803.27 cm -2 and minimum is observed at leaf apex as 5243.90 cm -2, on abaxial surface it is maximum at leaf margin as 6967.13 cm -2 and minimum at leaf lamina as 6065.57 cm -2. While in Zizyphus jujube on adaxial surface it is maximum at leaf base as 14098.36 cm -2 and minimum at leaf apex as 11885.24 cm -2, on abaxial surface it is maximum at leaf midrib as 15081.96 cm -2 and minimum at leaf apex as 11885.24 cm -2. Similarly in Holoptelea integrifolia, the epidermal frequency is maximum at leaf margin as 26229.50 cm -2 and minimum at leaf base as 24918.03 cm -2, on abaxial surface it is maximum at leaf margin as 26229.50 cm -2 and minimum at leaf base as 23360.65 cm -2 (Table - 6). Epideramal Index: Epidermal index is defined as the number of epidermal cells present in unit area to the number of epidermal cells. In Datura metal, the epidermal index on adaxial surface is maximum at leaf apex as 78.62 cells per unit area and minimum at leaf lamina as 69.83 cells per unit area, on abaxial surface it is maximum at leaf midrib as 81.56 cells per unit area and minimum at leaf margin as 63.91 cells per unit area. While in Celestrus emarginata, on adaxial surface it is maximum at leaf base as 88.07 cells per unit area and minimum at leaf lamina as 82.14 cells per unit area, on abaxial surface it is maximum at leaf lamina as 85.45 cells per unit area and minimum at leaf midrib as 77.55 cells per unit area. In Euphorbia hirta on adaxial surface it is maximum at leaf lamina as 87.05 cells per unit area and minimum at leaf midrib as 79.04, on abaxial surface it is maximum at leaf base as 76.36 cells per unit area and minimum at leaf margin as 72.64 cells per unit area. Whereas in Zizyphus jujube, on adaxial surface it is maximum at leaf midrib as 97.09 cells per unit area and minimum at leaf base as 93.47 cells per unit area, on abaxial surface it is maximum at leaf midrib as 96.84 cells per unit area and minimum at leaf margin as 92.26 cells per unit area. Similarly in Holoptelea integrifolia the epidermal index on adaxial surface is maximum at all the 5 locations of the leaf as 100 cells per unit area, on abaxial surface it is 124
maximum at leaf midrib as 95.70 cells per unit area and minimum at leaf margin as 95.63 cells per unit area (Table - 7). B. Costal Cells Costal cells: Costal cells are absent in all the studied taxa of Datura metal, Celestrus emarginata, Holoptelea integrifolia and Zizyphus jujube except in Euphorbia hirta, they are present only on abaxial side of the leaf and maximum are observed at leaf lamina region. 8.3.2. STOMATAL CELL COMPLEX Introduction The stomata has been considered as an important plant structure physiologically (Haberlandt 1914; Meidner and Mansfield, 1968) taxonomically (Mecalfe and Chalk, 1950; Stace, 1965.a,b; Van Cottem, 1970). The present investigation includes a detailed study of stomatal structure on leaves in the studied species. While the details of observations are presented as below: Stomatal types : Stomata were reported to be Anisocytic in Datura metal, Celestrus emarginata, and Anomocytic in Zizyphus jujube, Diacytic in Euphorbia hirta and Holoptelea integrifolia. Dominant stomatal types : Occurrence of more than one type of Stomata on the surface of the plant organ or on different organs in a species was first recognized by Briosi in 1981. The taxonomic significance of the stomatal variation was first brought into light by Shah et al, (1974). The dominant stomatal type is observed as anisocytic on the both the surfaces of the leaf in all the studied 5 taxa. 125
Shape of the guard cells: On the basis of shape and pair of guard cells they are distinguished into elliptic, circular widely or narrowly elliptic, three or four cornered, rectangular or dumbell shaped (Stace 1965a, Meidner and Mansfield, 1968: Esau, 1972: Fahn, 1974: Rajagopal and Ramayya, 1977) and stomatal pore is usually parallel to the guard cells but rarely transverse to the guard cells. In the present studied taxa, the shape of guard cells were observed to be with some difference in species as in Datura metal, the shape is circular widely elliptic on adaxial surface but it is circular narrowly elliptic on abaxial surface. Whereas in Celestrus emarginata, on both the surfaces, it is circular, narrowly elliptic in nature. In contrast to this in Euphorbia hirta and Ziziphus jujube, it is circular widely elliptic on both the surfaces but in Ziziphus jujube, the stomata are absent on adaxial surface. But it is quietly opposite in Holoptelea integrifolea, the shape of the guard cells is circular narrowly elliptic on both the adaxial and abaxial surfaces. And the stomatal pore is parallel to the guard cells in all the above studied taxa (Table -8) (Plate 3, a - f) (Plate 4, g - j). Position of the guard cells: Guard cells in relation to adjacent epidermal cells, could be either sunken, elevated or flushed with epidermal cells (Solereder, 1908: Metcalfe and Chalk, 1950: Easu, 1972) In the present studied taxa, the position of the guard cells are sunken in all the taxa of Datura metal, Celestrus emarginata, Euphorbia hirta and Holoptelea integrifolea but in Ziziphus jujube it is elevated (concave)to the adjacent epidermal cells. 126
Subsidiary cells: Cells surrounding the guard cells which are distinct or indistinct, are designated as subsidiary cells (Leelavathi, 1976; Prabhakar, 1978; Ramayya and Rajgopal, 1980; Vijay kumar, 1983). Depending on one or more cycles of subsidiaries are distinguished into monocyclic, bicyclic and tricyclic types (Pant and Banerji, 1965 c: Payne, 1970), intermediate conditions (1½, 2 ½ cyclic) between the above principal types are also recognized (Pant and Banerji, 1965 c: Leelavathi, 1976). The present studied taxa it is mostly monocyclic nature of subsidiary cells as seen in Datura metal, Euphorbia hirta and Holoptelea integrifolea on both the surfaces. Whereas in Celestrus emarginata and Ziziphus jujube it is tricyclic in nature on both the surfaces. Spatial relationship of stomata: Based on the association of the subsidiaries with the stomata, Rajagopal (1973) recognized the following three types of subsidiaries 1. Abutting type (a-type): When a subsidiary of stomata abute one or more subsidiaries of another stoma. 2. Common type (c-type): When a subsidiary abutes guard cells of two or more stomata. 3. Free type (f-type): When a subsidiary of stoma does not abute either a subsidiary or guard cell of another stoma. However in the presently studied taxa, the subsidiaries are mostly abutting type (a- type) as in Datura metal, Euphorbia hirta and Holoptelea integrifolea on both the surfaces. But it is free type (f-type) in Celestrus emarginata and Ziziphus jujube on both the surfaces. 127
Anticlinal walls of subsidiaries: Anticlinal walls of the subsidiaries are similar to the epidermal cells being straight on both the surfaces in all the studied taxa of Datura metal, Celestrus emarginata, Euphorbia hirta, Ziziphus jujube and Holoptelea integrifolea Distribution of stomata: Distribution of stomata in the leaves shows considerable variation (De Bary, 1984; Solereder, 1908; Metcalfe and Chalk, 1950). On the basis of presence of stomata, leaves are distinguished into four types viz., 1. Amphistomatic (present on both the sides of leaf). 2. Hypostomatic (present only on abaxial surface). 3. Epistomatic (present only on adaxial surface) (Florin, 1933; Esau, 1972) and 4. Astomatic (Rajagopal, 1973) stomata absent on both surfaces eg: Algae, further sub-categorized ampistomatic condition into the epiamphistomatic having greater percentage of stomata on the adaxial than on the abaxial; hypoamphistomatic with greater frequency of stomata on abaxial than on the adaxial. In the present study it is observed that the distribution of stomata is amphistomatic in Datura metal, Celestrus emarginata, Euphorbia hirta, Zizyphus jujube but it is epistomatic condition in Holoptelea integrifolea Orientation, Arrangement and Dispersion of stomata: Variation in orientation and arrangement of stomata in leaves are frequent and as such are of potential taxonomic tool (Rajagopal, 1973; Leelavathi et al., 1981). Stomata are variously oriented in leaves especially in those with reticulate venation, where as parallely oriented in the leaves with parallel venation (Esau, 1972; Fahn, 1967). 128
The stomata are variously oriented and are irregularly arranged in all of the studied species of Datura metal, Celestrus emarginata, Euphorbia hirta, Zizyphus jujube and Holoptelea integrifolia. Stomatal frequency and Stomatal index: Stomatal frequency is one of the most widely used characters in Pharmacognostic studies, but its significance in taxonomic studies has not yet been fully ascertained. According to (Stace, 1965.a,b), the distribution and frequency of stoma are of considerable taxonomic value. A large number of workers have used the stomatal frequency in-order to distinguish species with varying degree of success. However striking differences regarding the frequency of the stomata have been shown in number of plants grown in different environmental conditions (Salisbury, 1927) and in the leaves produced at different heights of the plant, in different sizes of the leaves from one surface to the other and also from one area of the surface of the leaf to the other As suggested by Salisbury (1927) the differences in the stomatal frequencies in a given taxon may be due to increase or decrease in the normal epidermal cell dimensions but the value of the stomatal index is independent of the size attained by the epidermal cells and hence is of more taxonomic value. follows: In the present studied taxa, stomatal frequency and stomatal index are observed as Stomatal frequency: The stomatal frequency is different in different species at each observed locations on the same leaf. It is defined as number of cells present in one Sq. centimeter (cm -2 ). The observations are as follows: In Datura metal, on adaxial surface the stomatal frequency is 129
maximum at leaf lamina as 44264.29 cm -2 and minimum at leaf apex as 20491.80 cm -2, on abaxial surface it is maximum at leaf margin as 28688.52 cm -2 and minimum at leaf base as 20491.80 cm -2. Whereas in Celestrus emarginata, on adaxial surface it is maximum at leaf apex as 27049.18 cm -2 and minimum at leaf base as 14754.09 cm -2, on abaxial surface it is maximum at leaf midrib as 27049.18 cm -2 and minimum at leaf lamina as 18032.78 cm -2. In Euphorbia hirta, on adaxial surface it is maximum at leaf mibrib as 18032.78 cm -2 and minimum at leaf apex as 9836.06 cm -2, on abaxial surface it is maximum at leaf margin as 26299.50 cm -2 and minimum at leaf apex and leaf midrib as 4918.03 cm -2. While in Zizyphus jujube, on adaxial surface it is maximum at leaf base as 9836.06 cm -2 and minimum at leaf apex and leaf midrib as 4098.36 cm -2 and on abaxial surface it is maximum at leaf margin as 10655.73 cm -2 and minimum at leaf apex and leaf midrib as 4918.03 cm -2. Similarly in Holoptelea integrifolia, on adaxial surface the stomata are absent but on abaxial surface the stomatal frequency is maximum at leaf midrib as 11639.34 cm -2 and minimum at leaf apex as 9180.32 cm- 2 (Table 9). Stomatal Index: Stomatal index is defined as the number of stomatal cells present in unit area to the number of epidermal cells. In Datura metal, on adaxial surface the stomatal index is maximum at leaf lamina s 30.16 cells per unit area and minimum at leaf apex as 21.36 cells per unit area, on abaxial surface it is maximum at leaf margin as 36.08 cells per unit area and minimum at leaf midrib as 18.43 cells per unit area. While in Celestrus emarginata, on adaxial surface it is maximum at leaf apex as 19.76 cells per unit area and minimum at leaf base as 11.92 cells per unit area, on abaxial surface it is maximum at leaf midrib as 22.44 cells per unit area and minimum at leaf base as 14.64 cells per unit area. In Euphorbia hirta, on adaxial surface it is maximum at leaf midrib as 20.95 cells per unit area and minimum at leaf margin as 15.55 cells per unit area, on abaxial surface it is maximum at leaf margin as 130
27.35 cells per unit area and minimum at leaf base as 23.63 cells per unit area. Whereas in Zizyphus jujube, on adaxial surface it is maximum at leaf base as 6.52 cells per unit area and minimum at leaf midrib as 2.90 cells per unit area, on abaxial surface it is maximum at leaf margin as 7.73 cells per unit area and minimum at leaf midrib as 3.15 cells per unit area. Similarly in Holoptelea integrifolia on adaxial surface the stomata are absent but on abaxial surface the stomatal index is maximum at leaf base as 4.43 cells per unit area and minimum at leaf apex as 3.38 cells per unit area (Table 10). 8.3.3. TRICHOME COMPLEX Introduction The use of epidermal appendages in taxonomy has been well recognized both in the extinct and extant plant material (Weiss, 1967; Solereder, 1908; Small, 1913; Netolitzky, 1932; Brown, 1938; Heintzelman and Howard, 1948). Presently a detailed investigation on structure, surface characters and the distribtuin of different types of trichomes in the 5 taxa have been investigated. The significance of the observations is discussed below: The following is the detailed description of trichomes presently recorded in the studied taxa along with their synonyms. Trichome distributinal patterns: Trichomes are said to be of universal occurrence in the angiopserms (Uphof, 1962) displaying great diversity not only in structure but also in distribution. Thus offering invaluable evidence for taxonomic purposes (Ramayya, 1962a;). Distribution of trichomes can be analyzed with reference to the presence or absence of the trichomes on a given surface of the organ as well as the area of occurrence on a given organ. 131
With reference to the first character lamellar organs have been categorized into the 4 following types by Vijay kumar (1983) viz: 1. Atrichiferous: leaves devoid of trichomes 2. Epitrichiferous: trichomes present only on the leaf adaxial 3. Hypotrichifereous: trichomes present only on the leaf abaxial 4. Amphitrichifereous: trichomes present on either surfaces of the leaf The distribution and type of the trichomes in the studied taxa are different in individual taxa as in Datura metal, the type of trichomes are uniseriate, multicellular and amphitricous. But they are completely absent in Celestrus emarginata. whereas in Euphorbia hirta, they are uniseriate, multicellular and epitrichous type. The trichomes are uniseriate, multicellular and hypotrichous in nature in Ziziphus jujube. While in Holoptelea integrifolia, they are uniseriate, unicellular and hypotrichous type. 132
C E E A C A a b C E C E A A c d E C E A A C e f Plate - 1 fig a is upper epidermis of Datura metal, fig b is lower epidermis of Datura metal fig c is upper epidermis of Celestrus emarginata, fig d is lower epidermis of Celestrus emarginata fig e is upper epidermis of Euphorbia hirta, fig f is lower epidermis of Euphorbia hirta E is epidermal cell shape, C is cytoplasm of the cell. A is anticlinal walls of epidermal cells 133
E A E A C C g h E A E A C C i j Plate - 2 fig g is upper epidermis of Zizyphus jujube, fig h is lower epidermis of Zizyphus jujube fig i is upper epidermis of Holoptelea integrifolia, fig j is lower epidermis of Holoptelea integrifolia E is epidermal cell shape, C is cytoplasm of the cell. A is anticlinal walls of epidermal cells 134
G S S G a b S S G G c d S S G G e f Plate - 3 fig a is upper epidermis of Datura metal, fig b is lower epidermis of Datura metal fig c is upper epidermis of Celestrus emarginata, fig d is lower epidermis of Celestrus emarginata fig e is upper epidermis of Euphorbia hirta, fig f is lower epidermis of Euphorbia hirta S is stomatal cell, G is shape of the guard cell 135
G S g h G G S S i j Plate - 4 fig g is upper epidermis of Zizyphus jujube, fig h is lower epidermis of Zizyphus jujube fig i is upper epidermis of Holoptelea integrifolia, fig j is lower epidermis of Holoptelea integrifolia S is stomatal cell, G is shape of the guard cell 136
TABLE -3 SHOWING THE SHAPE OF LEAF EPIDEMALS CELLS S.No. NAME OF THE PLANT SHAPE OF THE EPIDERMAL CELLS 1 Datura metal, Linn. Solanaceae 2 Celestrus emarginata, Grah./ Celestraceae 3 Euphorbia hirta, Linn./ Euphorbiaceae 4 Zizyphus jujube, Lamk./ Rhamnaceae 5 Holoptelea integrifolia, Planch/ Euphorbiaceae ADAXIAL SURFACE rectangular non-linear polygonal anisodiametric linear squarish polygonal isodiametric polygonal anisodiametric non-linear ABAXIAL SURFACE rectangular non-linear polygonal anisodiametric linear rectangular non-linear polygonal isodiametric rectangular linear 137
TABLE -4 SHOWING THE CHARACTERS OF CYTOPLASM AND SURFACE OF LEAF EPIDEMALS CELLS S.No. NAME OF THE PLANT CYTOPLASM CHARACTERS CELL SURFACE CHARACTERS ADAXIAL SURFACE ABAXIAL SURFACE ADAXIAL SURFACE ABAXIAL SURFACE 1 Datura metal, Linn. Solanaceae 2 Celestrus emarginata, Grah./ Celestraceae 3 Euphorbia hirta, Linn./ Euphorbiaceae 4 Zizyphus jujube, Lamk./ Rhamnaceae 5 Holoptelea integrifolia, Planch/ Euphorbiaceae Dense Dense Smooth Smooth Dense Dense Smooth Smooth Dcanty and translucent Dcanty and translucent Granulate Granulate Dense Dense Smooth Smooth Dense Dense Smooth Smooth 138
TABLE -5 SHOWING THE CHARACTERS OF ANTICLINAL WALLS, ARRANGEMENT AND ORIENTATION OF LEAF EPIDEMALS CELLS S.No. NAME OF THE PLANT ANTICLINAL WALL CHARACTERS ARRANGEMENT AND ORIENTATION ADAXIAL SURFACE ABAXIAL SURFACE ADAXIAL SURFACE ABAXIAL SURFACE 1 Datura metal, Linn. Solanaceae 2 Celestrus emarginata, Grah./ Celestraceae 3 Euphorbia hirta, Linn./ Euphorbiaceae 4 Zizyphus jujube, Lamk./ Rhamnaceae 5 Holoptelea integrifolia, Planch/ Euphorbiaceae Curved Curved Irregularly arrange and variously Straight Straight Irregularly arrange and variously Sinuate Sinuate Irregularly arrange and variously Straight Straight Irregularly arrange and variously Straight Straight Irregularly arrange and variously Irregularly arrange and variously Irregularly arrange and variously Irregularly arrange and variously Irregularly arrange and variously Irregularly arrange and variously 139
TABLE -6 SHOWING THE MAXIMUM AND MINIMUM EPIDERMAL CELL FREQUENCY ON ADAXIAL AND ABAXIAL SURFACES OF THE LEAF S.No. NAME OF THE PLANT EPIDEMAL FREQUENCY ADAXIAL SURFACE ABAXIAL SURFACE MAXIMUM MINIMUM MAXIMUM MINIMUM 1 Datura metal, Linn. Solanaceae 2 Celestrus emarginata, Grah./ Celestraceae 3 Euphorbia hirta, Linn./ Euphorbiaceae 4 Zizyphus jujube, Lamk./ Rhamnaceae 5 Holoptelea integrifolia, Planch/ Euphorbiaceae 94962.29 (LB) 12459.01 (LL) 94262.29 (LMR) 50819.67 (LM) 10918.03 (LB) 9426.22 (LL) 11008.19 (LB) 9385.24 (LMR) 68032.78 (LMR) 52439.01 (LA) 69672.13 (LM) 60655.73 (LL) 14098.36 (LB) 11885.24 (LA) 15081.96 (LMR) 11885.24 (LA) 26229.50 (LM) 24918.03 (LB) 26229.50 (LM) 23360.65 (LB) *location on leaf LA= Leaf apex, LB=Leaf base, LMR= Leaf midrib, LM= Leaf margin, LL= Leaf lamina 140
TABLE -7 SHOWING THE MAXIMUM AND MINIMUM EPIDERMAL INDEX ON ADAXIAL AND ABAXIAL SURFACES OF THE LEAF S.No. NAME OF THE PLANT EPIDERMAL INDEX ADAXIAL SURFACE ABAXIAL SURFACE MAX MIN MAX MIN 1 Datura metal, Linn. 78.62 (LA) 69.83 (LL) 81.56 (LMR) 63.91 (LM) Solanaceae 2 Celestrus emarginata, 88.07 (LB) 82.14 (LL) 85.45 (LL) 77.55 (LMR) Grah./ Celestraceae 3 Euphorbia hirta, Linn./ 87.05 (LL) 79.04 (LMR) 76.36 (LB) 72.64 (LM) Euphorbiaceae 4 Zizyphus jujube, Lamk./ 97.09 (LMR) 93.47 (LB) 96.84 (LMR) 92.26 (LM) Rhamnaceae 5 Holoptelea integrifolia, Planch/ Euphorbiaceae 100 (on all locations) 95.70 (LMR) 95.63 (LM) *location on leaf LA= Leaf apex, LB=Leaf base, LMR= Leaf midrib, LM= Leaf margin, LL= Leaf lamina *location on leaf LA= Leaf apex, LB=Leaf base, LMR= Leaf midrib, LM= Leaf margin, LL= Leaf lamina 141
TABLE -8 SHOWING THE SHAPE OF THE GUARD CELLS OF THE STOMATA ON ADAXIAL AND ABAXIAL SURFACES OF THE LEAF EPIDERMIS S.No. NAME OF THE PLANT SHAPE OF THE GUARD CELLS ADAXIAL SURFACE ABAXIAL SURFACE 1 Datura metal, Linn. Solanaceae circular widely elliptic circular narrowly elliptic 2 Celestrus emarginata, Grah./ Celestraceae circular narrowly elliptic 3 Euphorbia hirta, Linn./ Euphorbiaceae circular widely elliptic 4 Zizyphus jujube, Lamk./ Rhamnaceae ABSENT circular widely elliptic 5 Holoptelea integrifolia, Planch/ Euphorbiaceae circular narrowly elliptic 142
TABLE -9 SHOWING THE MAXIMUM AND MINIMUM STOMATAL FREQUENCY ON ADAXIAL AND ABAXIAL SURFACES OF THE LEAF EPIDEMIS S.No. NAME OF THE PLANT STOMATAL FREQUENCY ADAXIAL SURFACE ABAXIAL SURFACE MAXIMUM MINIMUM MAXIMUM MINIMUM 1 Datura metal, Linn. Solanaceae 2 Celestrus emarginata, Grah./ Celestraceae 3 Euphorbia hirta, Linn./ Euphorbiaceae 4 Zizyphus jujube, Lamk./ Rhamnaceae 5 Holoptelea integrifolia, Planch/ Euphorbiaceae 44262.29 (LL) 20491.80 (LA) 28688.52 (LM) 20491.80 (LB) 27049.18 (LA) 14754.09 (LB) 27049.18 (LMR) 18032.78 (LL) 18032.78 (LMR) 9836.06 (LA) 26229.50 (LM) 4918.03(LA,LMR) 9836.06 (LB) 4098.36 (LA,LMR) 10655.73 (LM) 4918.03 (LA,LMR) ABSENT 11639.34 (LMR) 9180.32 (LA) *location on leaf LA= Leaf apex, LB=Leaf base, LMR= Leaf midrib, LM= Leaf margin, LL= Leaf lamina 143
TABLE -10 SHOWING THE MAXIMUM AND MINIMUM STOMATAL INDEX ON ADAXIAL AND ABAXIAL SURFACES OF THE LEAF EPIDEMIS S.No. NAME OF THE PLANT STOMATAL INDEX ADAXIAL SURFACE ABAXIAL SURFACE MAX MIN MAX MIN 1 Datura metal, Linn. 30.16 (LL) 21.36 (LA) 36.08 (LM) 18.43 (LMR) Solanaceae 2 Celestrus emarginata, 19.76 (LA) 11.92 (LB) 22.44 (LMR) 14.64 (LB) Grah./ Celestraceae 3 Euphorbia hirta, Linn./ 20.95 (LMR) 15.55 (LM) 27.35 (LM) 23.63 (LB) Euphorbiaceae 4 Zizyphus jujube, Lamk./ Rhamnaceae 6.52 (LB) 2.90 (LMR) 7.73 (LM) 3.15 (LMR) 5 Holoptelea integrifolia, Planch/ Euphorbiaceae ABSENT 4.43 (LB) 3.38 (LA) *location on leaf LA= Leaf apex, LB=Leaf base, LMR= Leaf midrib, LM= Leaf margin, LL= Leaf lamina 144