Some Nigerian Species

The Japanese Society for Plant Systematics

The JapaneseSociety forPlant Systematics

ISSN OOOI-6799 Acta Phytotax. Geobot. 47 (1): ^41-46 (1996)

Cuticular Studies

^of

Some Nigerian Species

of

Senna ^{Tourn. ex} Mill. (Syn. ^{Cassia Tourn. ex L.):}

Leguminosae-Caesalpinioideae

H. O, EDEOGA

^and

PATRICIA I. OSAWE

Dqpartment

ofBotany,

^{Edo State}Uhivens'ity,P.M. B.I4,Ekpoma, Edo

State,

Nigeria

Abstract. A comparative study of theleafepidermis of fiveNigerian

leguminous

species

has been done

using the"light microscope. Some of the cHfferences reeorded inthe epidermal cell walt architecture, trichomes, size, distribution,frequency and morphology of the stomatal complex havc been discussedinlinewith theirtaxonomic significance.

The

nature of the uni- cellular andi multicellular

uichomes

are

described for

the

first

tirneinthese species of Senna,

and S.hirstttaisdiagnostic

in

acquisition of these two types of trichomes, The stomatal index

varied

from 47.1 % (S.

spectabilis) to

98.2 % (S.

^alata).

Key

Words:

leaf,

Legumono$ae, Senna,triehome ReceivedOctober 27,1995;accq)ted May

Z

^I996

According to Airy Shaw (1973), ^{Senna Tourn,}

^ex

^Mill. (Syn. ^Cassia

Tourn.

ex

L.) is

a

large genus

^{of about}

600

species

distrjbuted in tropical

and warm

temperate

regions of

the

world.

There

are about

22 indigenous

species and some aliens

in West Africa

which are used

for

medicinal and

decorative _purposes.

Morphological features

of some species of

Senna including S.

aiata

(L.)

Roxb.; S. hirsuta (L.) ^{H. S. Irwin & Bameby, S.}

occidentalis

Link., S.

obtusijblia

(L.) ^{H, S. Irwin & Barneby}

^and

^S. spectabilis (DC.) ^{I-I. S,}

Irwin & Barneby have been described by Hutchinson and Dalziel (1968)

and

Akobundu

and

Agyakwa (1987). ^The

^{stems are either} cylindrical or

ribbed

and woody and

therefore

can support

themselves. The leaves

are

petioiate

^{and vary}

in

shape

depending

on

the

species.

Many

^workers

have demonstrated the

_value

of

epidermal characteris-

tics in tracing the

relationship of

different taxa. They include Metcalfe

and

Chalk (1950), ^Stebbins

^and

^Khush (1961), ^Pa}iwal (1966),Cutler (1978),

Shah (1968, ^{1969, 1971), Shah}

^and

^Gopal (1969), ^Dehgan (1980), ^Gill

^et

al.

(1982), ^Gill

^and

^Karatela (1982, ^{1983, 1995), Edeoga} (1991), ^Gill

^and

Karatela (1983),

^and

^{found that in}

^{the mature epiderfnis of members of}

the Asclepiadaceae, the

upper epidermal cells are mostly

hexagonal

^with

anticlinal and

periclinal

^walls.

Conversely the lower

epidermal cells are elongated and

their

walls are sinuous.

Similarly Edeoga (1991) ^described

the

epidermal cells of

two Costus

species: namely,

C.

cofl7r

Ker-Gawl,

and

C. Iucanusianus Braun-Blanq. & K. Schum.,

observing

that the

upper

42

Acta Phytotax. Geobot, Vol, 47

epidermal cells of

the leaf

of

C.

cofierare

hexagenal

and

their leaves

amphistomatic.

^{Some Cassia}

^species

^have

^now

^been

^changed

^to Senna

species

(Lowe

and

Soladoye, 1990). Taxonomic

studies on wide

geographic basis

may show

that

a

particular ^taxon in

one country

is in fact the

same as another

name.

Such

studies may

indicate that

a

particular genus

^should

be

split

into

more separate

genera,

^as

Cassia has been divided into Cassia, Senna

and

Chamaecrista.

This

recent separation of

Senna

species

from Cassia

species shows

that there is

need

to

ascertain

the taxonomic

characters which are unique

to this

new

genus. As

^{a new}

taxon, information

about

it is incomplete; thus it is

an attempt

to fi11 in the gap in

our

present knowledge that the present

work was carried out.

Materials and Methods

Mature

and

fresh leaves

of

the five Senna

species

(S. ^{hirsuta, S.}

^obtu-

sijblia,

S.

alata,

S.

occidentlis and

S. spectabilis)

^{were collected}

(Inamdar,

1968) from different parts

^{of southern}

Nigeria. Samplings

were made

by

using

fresh leaves from _plants in their

natural conditions. ^rlhese

do

not undergo any

form

of

deteriolation

since

the leaves

were succulent.

These

materials were used

for the

epidermal studies

fo11owing the

method of

Cut- ler (1978)

^{with slight} modifications.

Epidermal peels

^{were stained with}

1 %

ethanol safranin and

temporarily

mounted

in

aqueous

glycerine

^solution.

The

slides were studied under a

tight

miscroscope and

photomicrographs

^of

epidermal cells including stomata and trichomes taken

using

a Carlzeiss Jenaval

miscroscope

fitted

with

MF AKS 24 × 36

automatic camera.

Sto-

matal

index was also caiculated. For the terminology

used

in this study see

Metcalfe

and

Chalk (1950).

Observations

The

cuticular characters were very

important in

all

the Senna

species

investigated

and were summarized

in Table 1. The

epidermal cells of

these

Senna species were

^varied

in shape and were either irregular or sinuous,

slightly sinuous and coarsely sinuous.

The

epidermal cells ranged

from pentagonal, hexagonal to polygonal,

Paracytic

^{stomata were observed}

in

^all

the

species

but Senna

^{alata and}

S. spectabilis; ^the latter two

species

have both paracytic

^{and anisocytic sto-}

mata

in the

upper epidermis

but

only

paracytic

^stomata

in the lower

epidermis

(Fig. ^{1-9). Two}

^major

^types

^of

^hairs

^{were observed}

^{in this}

genus:

unicellular and multicellular

trichomes (Fig. ^{10-12). S. hirsuta had}

both

unicellular and multicellular

trichomes

while

S.

alata,

S.

occidentalis,

S.

obtusijiolia and

S. spectabilis possesses

unicellular

trichomes

only.

The

stomatal

distribution in both the

upper and

lower

epidermis was also observed

to be

significant.

Thus the

stomatal

index

varied

from 47.1

The Japanese Society for Plant Systematics

The JapaneseSoclety forPlant Systematics

June 1996 EDEOGA & OSAWE: Cuticular

studies

in Senna 43

FIGs. 1-4, 1

and

2.

Lower and upper epidermis of

Senna

obtuhijblia.

Stornata

are

paracytic

^{and the epidermal celLs are varied} inshape

(

^×

^200).

^{3 and 4.Lower and upper epidermis of S.} oc'(,identa-

^{lis.Stomata are}

paracytic

^{and the epidermal cells polygonalor almost}

irregular in

shape

(

^×

^200).

% in Senna spectabilis ^to 98.2 % in S.

alata.

Of great importance to

note

was

the

close range of

the

stomatal

indices in both the

upper and

lower

epidermis

in

all

the taxa

studied,

Discussion

^Metcalfe

^and

Chalk (l9SO) ^had

^earlier

^{described the}

^{aspects of mature}

epidermis

in

a number of mature

plants including Senna. The

epidermal characteristics of

the five

species studied showed

that the

epidermal cell wall

patterns

^were

^{straight, slightly sinuous,}

^or

^coarsely

^sinuous.

^{The de-} gree

^{of sinuousity according}

^to Esau (1965) ^is

^caused

^{by the degree}

^of

force exerted on the stomata in their

course of

development.

In the presently investigated taxa, the leaves

were observed

to be

amphistomatic.

The

stomatal

indices

were

higher

on

the lower

epidermis compared

to the

upper

surfaces. These species also showed the existence

of variable stomatal

types: paracytic

^and anisocytic.

This did

not agree with

Metcalfe

and

Chalk)s (1950)

^{reports which}

^{indicated that the}

^stomatal

types of all the species

^were

paracytic. ^Paracytic

^{stomata were observed}

in

all

the five

species studied;

in

addition,

Senna

alata and

S.

spectabilis

showed anisocytic stomatal

type. ^･

Most

of

the

species studied

had high

stomatal

index

and

this had

ear-

lier been

reported

by Gill

and

Karatela (1985)

^and

^Gill

^{et al.}

(1983) ⁱⁿ

Asclepiadaceae

and

Leguminosae. All the five

species

investigated had

44 Acta Phytotax, Geobot, Vol, 47

FIGs.5-8. 5 and 6,Lower and upper epidermis et Senna hirsuta.Sromata are

paracytic

^{and the epidermal cells are sinuous} inboth surfaces

(

^{× 125 and × 200.} respectively). 7 and 8.Lowcr ^epidermis

in S.

atata alld

S.

spectabilis respectively.

Both

_paracyticand anisocyetic stomata arc

present^{and the epidermal ce}ls are} polygonal

(

^{× 200),}

[I/ABLE1.

Cuticular

characteristics of the Senna species studied

Character

Stomatalindex

(%)

S,atataS. occidentalis S.obtusijbliaS. hirszataS. spectabilis

Stomataltype

Shape ofepidermal cells

Trichome

Upper ^;

87.3 Lower

⁼

98.2

Paracytic&

anisocvtic

"

Mostly hexagonal

Unicellular

58.166,1

Paracytic

Varied,hexa- gonaltopolygonal

Unicellular

72.692.S

Paracytic

Mostlypolygonal

Unicellular

61.168.4

Paracvtic

Polygonal

&

sinuous

Unicellular

47.150.1

?aracytic

& anisocytic

Polygonal

&

sinuous

Unicellular Rows of cells

per ^trichome

1

1

1

3 1

trichomes

on

the

abaxial surfaces of

the leaf but the

cell architecture

however differed. Thus they

_were unicellular

in

all

the

species except

in S.

hins"ta

where

they

were

both

unicellular and multicellular

(Figs. ¹¹

^and

12). Similarly in

all

the

species

there

was one row of cell

per ^trichome

^ex-

cept

in S. hinsuta

^which

had

^up

to three

rows,

This

observation was

in Iine

with

that

of earlier authors

that had

vividly exphasized

the taxonomic im-

The Japanese Society for Plant Systematics

The JapaneseSoclety forPlant Systematics

June 1996 EDEOGA & OSAWE: Cuticular

studies

in Senna ⁴⁵

FIGs,9-12. 9.Upper epidermis of Senna spectahitis.Note the presence ^of

paracytic

^{ancl anisocytic stomata}

(

^×

^{200). Ie. Lower}

^{cpidormis of}

^S.

^{alata showing a} unicellular trichome

(

^{× 12S).11.}

Lower ^{epidermis of} S.htrsutashowing unicellular trichomes

(

^{× 62.5).12.Lowcr epidcrinis of}

^S,

hirsuta

showing a multicellular trichome

(

^{× 62,5).}

portance

^of

^trichomes in

making reliable

taxonomic

conclusions

(Metcalfe

and

Chalk, 1995; Stace, 1980; Edeoga, 1991; Nyawuame

and

Gill, 1991).

The possession

^of

paracytic

^{and anisocytic stomata}

brought to ]ight the

phylogenetic

relationship of

these Senna species. Inspite of this, S. hirsuta

and

S.

^{alam exhibited cuticular attributes}

that

cou]d

be

used

in

separating

them from the

other

taxa investigated. Though the

recent separation of some of

these Senna

species

from Cassia is

still

being questioned by

some authors,

the

epidermal

features

seemed

to

support such move.

Despite this

support, more

investigations in

other

lines

of

taxonomic

reasonings could

be initiated

such as

phytochemistry

^{and cytology}

in these taxa. This

^will

_go

^a

long

way

in

clearing

the

confusions

in the taxonomy

of

these Senna

species.

References

Airy Shaw, H. K, 1973. J. C, Willis' Dictionary

of the

Flowering Plants

and

Ferns. 8th

ed.

Cambridge University Press, Cambridge.

Akobundu, I. O.

and

C.

W. Agyakwa. 1987, A

Handbook

of

West African Weeds. 521 pp.

International Institute

of

Tropical Agriculture, Ibadan,

Cutler, D, F, 1978. Applied Plant Anaromy. 103 pp. Longmans, London.

Dehgan, B. 1980, Application of epidermal morphology to taxonomic

delimitation

of the

genus Jatropha (Euphorbiaceae). ^{Bot. J. Linn. Soc, 80; 258-270,}

Edeoga, H, O. 1991, Comparative

inorphology of the

leaf

epidcrmis

in Costt{s

tij}er-C.

Iucanusianus (Costaceae)

^{complex and}

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importance,

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Calotropis

　

procera



Ait ．



f _．（ Ascle−

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^Ca

^∬

^ia

^species

（ Leguminosae ）．



Iselya



_{2（ 3）}

：

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G ．0 ．

　

Olabanli

　and 　

S．

　W

．

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．

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． 1982．



Studies

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distribution

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in

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Niger ｛

an　

legumes ．

　

W ｛ lldenowia

　

12

：

87− 94 ． Hutchinson ，

　

J ^．

　and 

M ．

　

J．

　

Dalziel． ．

1968．

　

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West

　

Tropical

　

Africa ． 606

　

pp ．



Crown 　　　Agents

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Overseas

　

Government

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Admin ｛

stration

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J，

　

A ．1968，

　

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541− 552 ．

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Some

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^{ln　some 　members 　of}

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Bot ．35

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745− 759 ．

　　　　　　　

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^．



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Edward

　

Arnold

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_，　

G ，

　

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Variation

　

in

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the

stomatal com

− 　　　 plex



ⁱⁿ

^the

^leaf

^{epidermis 　of}monocotyledons 　and 　

its

　

bearing

　on 　their　

phylogeny．

　　　 Amer ．



J ．



Bot ． 48

；

51 ⁻ 57 ，

摘 要

エ デ

オ ガ

_，

H ．0 ．・P ．1． オ サ ウ

ェ ：

ナ イ

ジェ

リ ア

産

Senna

_（^＝ カ

ワ ラ

ケ

ツ ^メ イ 属 ）（

^マ

^メ

科 ジ

ャ

ケ

ツ イ ^バ ラ 亜

科

）

数 種

^の

表 皮 系

^の

比 較 研 究

　 　 ^ナ

^イ

^ジ

^ェ

^{リ ア}

^産

^{Senna （＝ カ ワ ラ}

^ケ

^{ツ メ}

^イ属

^）（

^マ

^メ

^{科 ジャ}

^{ケ ッ}

^イバ

^{ラ 亜} 科） ^の 5 種 ^の

表 皮 系

^に

^{つ い}

^て

， 光 学

顕

微 鏡

に よ り比

較 研 究

^を

行^っ

^た ．

_毛

や

気 孔

^の

形 態

^の

違^い

に

基

^づ

^い

て ， ^{そ れ}

ら

^の 分 類 学 的 意 義

^を

議 論

し ^た ． ∫

飢 翩

癖

∫磁

は

単 細 胞

^の

毛

^と

多 細 胞

^の

毛 を も^つ 点

で

他

の 種

と

区 別

^{さ れ る こ と が}

明 か

^に

さ れ

，

^{同 時}

^に Senna

_属

が ^こ れ ら 二

^つ

の

毛

^を

も^つ

^{こ と}

が 初

^{め て}

記

録 さ れ た ．

（ ^ナ

^イ

^ジ

^ェ

^{リ ア} ，

^エ

^ド

州

^{立 大}

学

，

植 物 学 研 究 室

）