Proc. Indian Acad. Sci. ( Sei.), Vol. 96, No. 2, June 1986, pp. 113-120. Printed in India.

Contribution to the leaf anatomy of the genus Rich

M SURYANARAYANA RAJU, V SESHAVATHARAM and S APPA RAO* Department of Botany, Andhra University, Waltair 530 003, India *Genetic Resources Unit, International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 324, India MS received 21 December 1985; revised 1 May 1986 Abstraet. Leaf epidermal patterns in 18 belonging to the genus Pennisetum Rieh., were described. The va¡ in the leaf epidermal characters was utilized for the identification of species. Macro hairs were reeorded only in Pennisetum americanum, Pennisetum clandestinum, Pennisetum polystachyon, Pennisetum pedicellatum, Pennisetum villosum, Pennisetum cenchroides, Pennisetum purpureum• typhoides 0aybrid) and Pennisetum orientale. Short cells between the veins were paired, solitary or more than two celled. Prickle hairs were absent only in Pennisetum polystachyon. Hooks were absent ordy in Pennisetum hohenackeri and Pennisetum squammulatum. Stomata with triangular subsidiary cells occur in all the species. Silica bodies are of various types. A dichotomous key was prepared based on epidermal characters for the identification of the different species studied. Keyworfls. Pennisetum; Gramineae; epidermis.

1. Introduction

Leaf epidermal morphology is now considered as one of the most important tools in understanding the phylogeny and interrelationships of various families of angiosperms. The epidermal patterns attained a high degree of specialization and differentiation in the family Gramineae. As early as in 1932-1936 Prat utilized these characters in the classification of the grasses and believed that these characters were reflecting their true relationships more exactly than spikelet characters. Several subsequent workers studied the epidermis in the Gramineae. Metcalfe (1960) in his monumental work described in detail the leaf anatomy of 206 genera and 413 species. The present study aims at the leaf epidermal morphology of 18 species belonging to the genus Pennisetum.

2. Materials and methods

Al1 species of the genus Pennisetum Rich., except P. hohenackeri were collected from the growing at ICRISAT, Hyderabad. P. hohenackeri was collected from Araku, Andhra Pradesh. A fully matured leaf (4th from the base) was collected in each case. The portion of the blade examined was about 9 cm from the sheath. The peelings were made by scraping the epidermis with a sharp blade following the method described by Metcalfe (1960). The preparations were stained with aqueous Safranin and were mounted in glycerol. In some cases, the method described by Mohan Ram and Vijayalaxmi Nayyar (1974) gave good results.

113 114 M Suryanarayana Raju, V Seshavatharam and S Appa Rao

3. Results

The epidermal patterns of both the abaxial and adaxial surfaces were studied giving emphasis to the nature of long and short cells, silica bodies, macro and micro hairs, prickle hairs, nature and dist¡ of stomata and interstomatal cells and papillae. The data has been summarised in table 1.

3.1 Macro hairs

Among 18 species investigated, macro hairs were recorded in P. polystachyon, P. americanum, P. clandestinum and P. pedicellatum on both the surfaces, and only on the adaxial surface in P. villosum, P. cenchroides, P. purpureum x typhoides (hybrid) and P. orientale. They are absent in the rest of the species investigated.

3.2 Micro hairs

Two-celled micro hairs are uniformly of the Panicoid type and occur in all the species studied, with a thick walled basal ceU anda hyaline thin walled distal ceU.

3.3 Long cells

Long cells are thin walled in P. pedicellatum, P. villosum, P. cenchroides, P. mezianum, P. ciliaris and P. divisum and thick waUed in the rest of the species investigated. The walls of the long cells are sinuous in the species except in P. purpureum. The walls are pitted in P. polystachyon, P. americanum, P. clandestinum, P. purpureum x typhoides (hybrid), P. purpureum, P. macrorum, P. hohenackeri, P. setaceum and P. squammulatum and ate non-pitted in the rest. Their size ranged from 98-6 x 28.0 la in P. macrorum to 238.5 x 40.8 q in P. americanum (table 2).

3.4 Short cells

On the abaxial surface, short cells over the veins ate in continuous rows of less than 10 cells in P. cenchroides, P. purFureum, P. macrostachium, P. ciliaris and P. divisum while in the rest they occur in long rows of more than 20 cells each. Short cells are absent on the intercostal region in P. pedicellatum and P. ciliaris; occur in rows of 3 cells in P. divisum; solitary in 1". polystachyon, P. clandestinum, P. purpureum x typhoides (hybfid), P. orientale, P. orientale x typhoides (hybrid), P. raacrorum and are paired in the rest of the species. On the adaxial surface short cells on the costal region are in short rows of less than 10 cells in all the species. Short cells between the veins are absent in P. clandestinum, P. pedicellatum, P. macrorum, P. mezianum and P. ciliaris; occur in 3 celled rows in P. divisum; solitary in P. purpureum x typhoides (hybrid), P. orientale x typhoides (hybrid) and paired in the rest. In size they range from 66-2 x 6.5 la in P.pedicellatum to 20.8 x 6.5 ~t in P. orienta& x typhoides (hybrid)o Table 1. Epidermal patterns in 18 speci'es of the genus Pennisetum.

Macro Prickle hairs hairs Hooks Long cell size Short cell size Interstomatal cell Name of the species Ab Ad Ab Ad Ab Ad (q (p) size Of)

P. polystachyon + + + + 167.04. 19"3 x 34"54.2-1 30.64.2-7x 6.84.0.0 121-34. ll.9x 36.24.2.3 P. americanum + + - + + + 238.5 4. 27.8 x 40.8 4.1-8 37.94.4-9x10.2• 164-94. 15-I x 48.64. 2-3 P. clandestinum + + - + + + 191.3 4. 34.2 x 39.8 4. 2.3 39.24.1.6x!0.24.0.0 60.7-4- 23.9 x 48.5 4. 1.5 P. pedicellatum + + - + + - 230"4+33'0• ~.24.1.6x 6.54.0.0 151.44-46.5 x 51.3 + 1.9 P. villosum - + - + + + 190.34.23-0 x 37"94.5"5 33.24.3.2• 6.54.0-0 119.44. 18.3 x 41-5 4.9.2 P. cenchroides - + + + + + 177"9 4. 19.4 x 36.5 4. 5.3 33.34.0-7x 6.54.0.0 93.5 4. 18.5 x 34.0 4. 2.6 P. purpureum x typhoides - + - + + + 102-94.25"0• 35.74.1.7x10.24.0.0 55.44. 10-8 x 35.54. I-6 (hybrid) P. orientale - + - + - + 170"2+40"2• 33-24.3.2x 6.54.0.0 96.5+ 14.5 x 31.84.2.3 P. purpureum + + + + 106"8 4.16"7 • 40"44- 2"5 22.9• 53-24- 6.9 x 51.04.3.9 P. macrostachium + + + + 187"04. 21"8 x 41"84-1"5 33.04.1.5• 77.64- 3.6 x 52.24. !-6 P. orientalextyphoides + + + 173"44. 25"7 x 39"9+ 2.2 ~.84.2-9• 6.54.0.0 89.3 4. 39.6 x 45.0 + 4.7 (hybrid) P. macrorum + + + 98.64.11-6 x 28"04. 2.5 26-5• 6-54.0.0 56.84. 19.3 • 28.44-3-7 P. hohenackeri + 118"7 4. 37"5 • 41"2 4. 1"6 45.34.2.0• 6.54.0.0 76.04. 16.6 • 40.24- 3.9 P. setaceum + + + + 160"84.44"5 x 31"84.4-1 32.34.1.7x 6.54.0.0 119.54.58-6• P. mezianum + + + + 206"24-37"6• 36'44.2"3 31-54.3.2• 183.24. 30.6 x 34.44-3.2 P. ciliaris + + + + 185-74.18"1 • 39.94.4.4 32.3•215 6.54.0.0 98.14. 19.5 • 50.54. 3-2 P. divisum + + + + 212-3 4.25.7 x 35"74.4"1 36.04.3.9x 6.54.0-0 118-74. 13-7 • 44.34- 8.4 P. squammulatum + 176"84- 25"0 x 44-24- 2"7 58-9• 8-24.1-6 101-94. 15.1 • 49-54.9.5 Ab, abaxial; Ad, adaxial; +, present; -, absr 116 M Suryanarayana Raju, V Seshavatharam and S Appa Rao

Table 2. Stomatal characters of the genus Pennisetum.

Stomatal frequency Stomatal index

Name of the speeies Stomatal size (q Abaxial Adaxial Abaxial Adaxial

P. polystachyon 67"2+1-4• 78.94-12.3 17.74- 2'3 17"54- 0-0 5.0+1.4 P. americanum 66"84-1.5x30.44-I.0 72"04-22.2 46"74-14-3 14"24- 3"2 11-54-4"2 P. clandestinum 70"54-1"4x45"0+3.3 102"44-13.2 26"34-10"1 21"44- 2"7 7"24-2"4 P. pedicellatum 86"84-2.3x44-94-4.1 62"64-17-1 26"94-11-8 14"94- 2"4 8"34-2"7 P. orientale 61"24-3"6x31.8+2.9 202"54-22"3 57"44-19"5 15-04-10'3 5"54-1'5 P. villosum 65"44-1"4x43.5+1.4 96"54-16"2 45'34-19"8 18"54- 2"7 9"74-4"4 P. cenchroides 51"84-1"4x33-4+0.7 149"24-12-4 91"24-19"2 21-54- 1"7 10"94-2'3 P. purpureum x 59-54-1.7x35.94-1.6 144"04-14.6 87-84-22-2 16-54- 1-6 13"04-2"9 typhoides 0aybrid) P. purpureum 53.24-1-6x42.04-1.6 177.94-34.3 105-34-15"6 19-04- 1"6 15.24-2.2 P. macrostachium 77.6-1-3-6x52.24-1-6 87"64-15-2 17"54- 0"0 15"84- 2.6 4.04-0.3 P. orientale • 70-14-2"4x40"8+0-0 149-84-22"5 17-54- 0-0 22"44- 4'2 3"04-0"2 typhoides (hybrid) P. macrorum 42.54-1.7• 230'24-50"0 105"34-10-2 19-54- 3'4 11-64-0"8 P. hohenackeri 60'74-1"1• 159"54-22"0 127"84-19"4 22'24- 2"7 16-04-2"2 P. setaceum 69"84-1"6• 95-24-13"8 32-24-17"2 15'34- 2"1 4"84-2-4 P. mezianum 65-04-2"6x35"54-2-3 97'64-17"0 159'34-22"7 19"34- 3"3 20-04-2-5 P. ciliaris 73"14-1"7• 81"94-14"3 93-54-14"3 16"24- 1"7 17"24-2"9 P. divisum 71"04-1.8x40.84-0.0 101"74- 7"8 87'74-26'8 17"84- 1"8 17'24-4"7 P. squammulatum 87"04-1'6• 67-44- 0"0 55"54-17"3 14"94- 2"6 11"34-2-9

3.5 Silica bodies

Silica bodies within the short cells are of different types. Silica bodies over the veins on the abaxial surface are horizontally elongated, sinuous in P. pedicellatum; intermediate between cross and dumb-bell shaped in P. purpureum x typhoides (hybrid); dumb-bell shaped in P. polystachyon, P. clandestinum, P. villosum, P. cenchroides, P. orientale, P. mezianum, P. ciliaris and P. divisum and are cross shaped in the rest. Silica bodies on the abaxial surface in the intercostal region are tall and narrow in P. polystachyon, P.a.mericanum, P. clandestinum, P. villosum, P. purpureum x typhoides (hybrid), P. orientale and P. macrorum and are tall-narrow, crenate in the rest of the species. On the adaxial surface silir bodies over the veins are dumb-bell shaped in P. polystachyon, P. cenchroides and P. squammulatum; horizontally elongated, sinuous in P. pedicellatum and P. divisum; intermediate between cross and dumb-bell shaped in P. purpureum x typhoides (hybrid), P. setaceum and P. ciliaris and are cross shaped in the rest. Silica bodies in the inter costal region are tall and narrow in P. polystachyon, P. americanum, P. villosum and P. purpureum x typhoides (hybrid) and in the rest they are tall-narrow, crenate.

3.6 Stomata

Stomata were present on both the surfaces with triangular subsidiary cells. Stomatal frequency varied from 230.2 4- 50.0 in P. macrorum to 62.6 4- 17.1 in P. pedicellatum on the abaxial surface and 159.3 4- 22.7 in P. mezianum to 17-5 4- 0-0 in P. macrostachium and P. orientale x typhoides (hybrid) on the adaxial surface. Stomatal index varied Leaf anatomy of the genus Pennisetum 117 from 22.4 + 3-2 in P. americanum on the abaxial and from 20.0 + 2.5 in P. mezianum to 3-0 + 0.2 in P. orientale x typhoides (hyb¡ on the adaxial surface (table 2). In size they ranged from 87-0+ 1.6x47.2+2.6tx in P. squammulatum to 42.5+ 1.7 x 32-3 + 1.7 I~ in P. macrorum (table 2).

3.7 Interstomatal cells

Interstomatal cells were long in all the species while in P. clandestinum, P. purpureum, P. macrostachium and P. macrorum they are short with concave ends. The size of the interstomatal cells varied from 53.2 x 51-0 ~t in P. purpureum to 183.2 x 34-0 ~t in P. mezianum (table 1).

3.8 Prickle hairs

P¡ hairs are absent from both the surfaces only in case of P. polystachyon. Prickle hairs are present on both the surfaces in P. cenchroides, P. purpureum, P. macrostachium, P. setaceum, P. mezianum, P. ciliaris and P. divisum. They are restricted to the adaxial surface only in P. americanum, P. clandestinum, P. pedicellatum, P. villosum, P. purpureumx typhoides (hybrid), P. orienta&, P. orientale x typhoides (hybrid), P. macrorum and P. squammulatum (table 1).

3.9 Hooks

Hooks are absent from both the surfaces in P. hohenackeri; absent on the abaxial surface only in P. orienta& and P. squammulatum; absent on the adaxial surface only in P. pedicellatum, while present on both the surfaces in the rest of the species (table 1).

3.10 Papillae

Papillae are present only in P. orienta& x typhoides (hybrid), P. ciliaris, P. divisum and P. squammulatum and were mostly associated with micro hairs.

4. Discussion

Leaf epidermal studies playa significant role in the grass systematics. The importance of the grass leafepidermis was first recognised by Krause (1909, 1910, 1912 and 1913). Subsequently, Avdulov (1931), Prat (1932, 1936), Wu (1962), Lee and Reynolds (1961), Leigh (1961), Roy (1963), Jauhar (1967), S¡ (1978) and Gautam and Sharma (1981 ) showed the leaf epidermal characters of several tribes of the Gramineae to be of diagnostic value for their identification and classification. According to Stebbins (1956) cell patterns are characteristic of a species and often diagnostic also of genera and tribes. Metcalfe (1960) observed that the leaf anatomical characters showed considerable variation in the family Gramineae. Brown (1958) considers that all the grasses except the Bambusae could be divided into two distinct groups as and Festucoideae based on the leal characters. 118 M Suryanarayana Raju, V Seshavatharam and S Appa Rao

Table 3. Correlation studies of leal epidermal characters in the genus Pennisetum. Inter- Long Stomatal Stomatai Shortcell stomatal eell Stomatal index frequency size cells size size Stomatal index Stomatal frequeney 0-4308 Short eeil size -0-2593 -0-4813 a Interstomatal eells - 0"4606 -0"7632b 0-3570 Long cell size - 0-3180 -0"6783b -0-4636 -0-0816 Stomatal size -0-3602 -0.7141 b 0-3565 0-4022 0.1526 aSignifieant at 5% level, ~ignhŸ at 1% level.

Two species namely P. clandestinum and P. macrorum studied presently has earlier been investigated by Metcalfe (1960) and the present data are in agreement with bis observation. The leaf epidermal features of all the 18 species investigated presently conform panicoid characters suggested by Metcalfe (1960). Out of the 18 species, 8 species differ from the others in having macro hairs (table 1). P. polystachyon is distinct from the rest of the speeies in the absence ofprickle hairs and P. hohenackeri and P. squammulatum by the absence of hooks. PapiUae occur in only 4 species studied presently viz P. orienta& x typhoides (hybrid), P. ciliaris, P. divisum and P. squammulatum. Micro hairs and stomata are uniformly of the same type in all the species investigated, though variations occur in their size, frequency etc. An attempt has been made to find out the correlations if any between the stomatal size, stomatal frequency, stomatal index, size oflong cells, short cells and interstomatal cells (table 3). The data reveal a negative correlation between stomatal frequency and stomatal index, long cell size, interstomatal cell size and short ceil size. A dichotomous key for the identification of the 18 species based on their leaf anatomical characters is given below:

(i) Macro hairs present 2 Macro hairs absent 9 (ii) Macro hairs present on both the surfaces 3 Macro hairs absent on the adaxial surface 6 (iii) Large prickle hairs absent on both the surfaces P. polystachyon Large prickle hairs present atleast on adaxial surface 4 (iv) Short cells absent between the veins; hooks absent on P. pedicellatum adaxial surface Short cell3 present between the veins; hooks present on both the surfaces 5 (v) Interstomatal eells long (more than 150 l~) P. americanum Interstomatal cells short (less than 75 ~) P. clandestinum (vi) Large p¡ hairs present on abaxial surface P. cenchroides Large pfickle hairs absent from abaxial sufface 7 (vii) Hooks absent on the adaxial surface P. orientale Hooks present on both the surfaces 8 Leaf anatomy of the genus Pennisetum !19

(viii) Short ceils paired between the veins P. villosum Short cells solitary between the veins P. purpureum x typhoides (hybrid) (ix) Large prickle hairs present on both surfaces 10 Large prickle hairs absent o¡ abaxial surface 15 (x) Long cells thick walled II Long celis thin walled 13 (xi) Interstomatai cells Iong (more than lO0 la) P. setaceum Interstomatal cells short (less than 60 q 12 (xii) Long cells pitted, non-sinuous P. purpureum Long ceils non-pitted, sinuous P. macrostachium (xiii) Papillae absent P. mezianum Papillae present 14 (xiv) Short cells between the veins absent P. ciliaris Short cells between the veins present P. divisum (xv) Papillae present 16 Papillae absent 17 (xvi) Hooks present P. orientale • typhoides (hyb¡ Hooks absent P. squammulatum (xvii) Hooks present P. macrorum Hooks absent P. hohenackeri

Acknowledgement One of the authors (MSR) is grateful to Council of Scientific and Indust¡ Research, New Delhi, for the award of a Fellowship.

References

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S¡ A K 1978 Study ofleafepidermal in the genus Digitaria Rich. (Gramineae); J. Indian Bot. Soc. 57 155-160 Stebbins G L 1956 Cytogenetics and evolution of grass family; Aro. J. Bot. 43 890-905 Wu M C Y 1962 The classification of bambuseae based on leaf anatomy; Bot. Bull. Acad. Sin. Taipei 3 83-108