3.2. CLIMA ESCOLAR
3.2.4. Clima social de aula: concepto desde el criterio de varios autores y de Moos y Trickett
The e c o lo g ic a l in flu en ces on Anthericum and Chlorophytum species has been reported by many authors (Obermeyer, 1962; Hanid, 1974; Marais and R e illy , 1978). Thus a comparative e c o lo g ic a l study has enabledone to fin d out which of the e co lo g ica l fa cto rs readily a f fe c t these plants. I t has been observed that the
e c o lo g ic a l influences on these plants can be considered from two points o f view:
i . the environmental fa cto rs and
i i . the in flu ence o f s o i l Chemical composition, which may a f f e c t the e c o lo g ic a l d istrib u tion s o f these plants.
MYMEanasa.ta3i Jüa&agaa es ;
Species o f both genera show a morphological response to
changes in the environment» I t i s observed that shade, temperature and re la tiv e humidity a ffe c t the morphology o f these plants.
The response, of C. alism ifolium put und er tree shade, a few metres from the greenhouse and those in the greenhouse gives a good example. Those in the shade grew very w ell with r e la tiv e ly longer p e tio le s and la rger laminae. Those in the greenhouse had short p e tio le s and smaller laminae. This can be due to the fact that
■^hose in the shade had lower rate o f transpiration because the area was co o le r than the greenhouse. I t therexore means that
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those could a ffo r d to expose larger le a f surface area since the transpiration would be le s s , Those in the greenhouse needed to reduce their le a f surface area to cut down excess transpiration, Larger and more green lamina would re su lt in higher production o f
carbohydrates through photosynthesis; thus more energy would be made available to plants in the shaded area, On the other hand,
small le a f surface area o f those in the greenhouse would resu lt in comparatively low photosynthetic products and lower energy f o r vegetative growth. Thus they were stimted in growth, Tliis pheno- menon was a lso observed in _C. macrophyllum, _C. la rum, R. inornatum a n d togoense. The openness or shadiness o f habitats had l i t t l e or no in flu ence on Anthericum sp ecies. This could be c lo s e ly rela ted to their habitats which were u su ally open f i e l d s in the savanna zone,
The specimens in the shade developed langer le a f p e tio le s while those in the greenhouse developed shorter le a f p e tio le s , _C. laxum co lle cte d from the open f i e l d in the North had no d e fin ite and d is tin ctiv e p e tio le in nature. In cu ltiv a tion under the shade, the same specimen developed w ell defined and d istin o t le a f p e tio le s, The p ossible reason could be that the production o f longer p e tio le in the shaded area helped the specimens to d isp lay their leaves, This w il l enable them to maximize the use o f the lig h t penetrating
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-through the shade fo r photosynthesis. Since the specimens in the open get even more than enough sunlight, the produetion of long p e tio le i s not neeessary. _C. a lis a ifo llu m , C,. macrophyllum
stenopetalum and C, inoraatma show this e c o lo g ic a l adaptation<ai so#
The development o f hairy structures or shining le a f surface i s a device to check excessive transpiration . This i s a lso an
environmental adaptation. g.. caulescens and blepharophylluia
co lle c te d from 'the North had hairy le a f surfaces. Then these specimens were cu ltiva ted in the Nursery, the hairy structures reduced g rea tly and eventually disappeared under sliade. Thus the possession o f hairy
le a f surface i s a means o f checking excess 'transpiration in an area where the supply o f water i s sca rce ly s u ffic ie n t . This adaptation was therefore found unnecessary when the water supply was s u ffic ie n t .
I t has been observed that environmental e c o lo g ic a l fa cto r s gen erally a ffe c t the size o f leaves and the presence o f hairs on the le a f surfaces,, Presence or absenoe o f p e tio le or rela tion sh ip of p e tio le to le a f blade i s a ls o ’ e c o lo g ic a lly influenced. Thus the use of any o f these characters fo r taxononic purpose w ill eventually create taxononic problem which i s now a feature o f th is complex. A specimen o f _C, inornatum or _C, alismi folium with l i t t l e or no p etiole may not be considered as the same species with one which has long, w ell developed p e t io le s . In the same way, a £ . blepharophylluia without h a iry le a f surface may be considered as another species
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d iffe r e n t from those with hairy le a f surfaee. There i s evidence in th is complex where two or more taxon orale names have been given to representative specimens o f the same taxon. Henee Obemeyer, (1962) reduced fiv e speeies of Chlorophytuia to synonyme. Hanid (1974)
enlarged the representatives of C_. a ffin e by adding nine speeies o f Anthericum and two speeies o f Chlorophytum. Hepper (1968) a lso reduced twenty-four speeies o f Anthericum in liest T ropical A frica to fourteen synonyms and f i f t y speeies o f Chlorophytum to twenty- one speeies.
I t must be noted that the marginal c ili a t i o n in C_. blepharophyllum i s not e c o lo g ic a lly induced. The cu ltivated specimens continued to exh ibit the marginal c ilia t io n o f th eir leaves.
S oil physical composition and i t s Chemical contents have great in flu ence on plants growing in i t . Anthericum and Chlorophytum taxa show p h y sio lo g ica l responses to s o i l Chemical composition. Since the s o i l composition gives 110 clue to the problem at hand, the data are only presented in the Appendix.
However, s o i l magnesium concentration seems to influence the d istrib u tio n o f these plants. A„ limosum. pterocaulon II
and A. pubirhachis have th eir s o i l Kg concentration ranging from 0.66me/l00g to 0.82me/l00g. On the other hand, Chlorophytum speeies
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-are found in s o il with r e la t iv e ly higher Mg concentration ranging from 1 ,24öe/1 00g to 3.51 d e /100g. I t i s evident that Anthericum thrives w ell in s o ils with lese than 1,0me/l 00g Mg++ while low s o i l Mg++ concentration ( i . e . below 1.0me/l00g) Limits, a t le a st in part,
the growth of Chlorophytum.
Mg i s an essen tia l constituent of C hlorophyll. I t i s a lso involved in enzyraatic rea ction s (iru o g , _et. _al, 1947) «
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CHAPTER 3
M ORPHOLO QIGAL STUDIES
Morphological or phenotypic characters are the attribu tes o f any organism which are commonly used in id en tify in g the or&anism. They are nanifeatatione o f the interplay o f genes, cytogenes, and the
environmental fa cto r s . Hence no meaningful relation sh ip can be drawn between two species or genera without considering th e ir
phenotypic characters. Thus the morphological stu dies w ill enable one to deteimine distin guish ing characters o f each species which can be found useful f o r hybridization and cytogenetic studies o f the two genera under consideration . This study can also be found useful in solving the taxonomic problems o f the group o f related genera in which Anthericum and Chiprophytum are included. To th is end, the morphological characters o f the l©aves, r o o ts , flo r a l parts and pollen grains were studied and analysed s t a t i s t i c a l l y . The q u a lita tive morphological characters were also investigated so as to fin d out whether such ch aracter(s) could be useful as diagn ostic character(s) fo r each species and/or genus.
Morphological characters were defined from the le a f apex, ^eaf • shape, le a f margin, type o f le a f base, colour o f le a f base, type of shoot, 'ahape o f ’ pseudosten;,,' lo ca tio n o f the root tuber(s) lo ca tio n and shape o f peduncle, type o f in florescen ce, colour o f tepals and anthers. Other characters investigated were the colou r and shape o f f r u i t s , d isp osition o f iep als at p o llin a tio n and number o f tepals.
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The wd.desl part o f eich l e a f blade, usually around. the middle, was measured and recorded, in cm. against the length o f the le a f.
The mean value was determined. . .
The le a f index was calculated as the ra tio o f length to the width i . e . Length
Width“
The number o f veins waS counted across the widest part o f the le a f blade with the aid o f X10 hand le n s. The mid--rib was not counted.
The number was recorded as usual.
The spacing of veins in each le a f was calculated as fo llo w sj Leaf Width x 10
No o f veins + 2
where the added 2 represented the two marginal spaces. The vein spacing in terval was recorded in m illim etres. The mean value was ca lcu la ted .
(b) Morpholpcfv . of.- Preserved Leaf.
Measnrements from herbarium specimens were taken across d iffe re n t h abitats, stages o f developments and v a rie tie s o f each sp ecies.
Counting o f veins on leaves was equally randomly sampled. Specimens at the herbaria o f the TJniversity o f Ibadan, University o f I fe and those at the Forest- ■ Research In stitu te o f Nigeria, Ibadan were a l l investigated. However, data fo r A. moniliforme was - • c o lle c te d
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38 -0 Root Morphology
Root length, tuber length and tuber circumf erenco were measured, as previously ou tlin ed, and recorded f o r each root in each specimen s t u d i e d . Five to ten 1*00ts were handled in each specimen and a tota l
o f 100 roots was handled in each sp e cie s. The mean values were
calculated and recorded. The number o f tu ber(s) was recorded fo r each root.
i i . Ratio o f Root Tuber; Root Length
The ra tio o f root tuber to the whole length o f each root was calculated by dividin g the root tuber length by the length o f the
ro o t. The quotient was m ultiplied by 100 and thus recorded as percentage.
The mean fo r each species was calculated and recorded.
D Floral Morphology
The length o f at lea st twenty peduncles was taken fo r each species a fte r the fr u its had been developed or a fte r flow ering in such cases where fru its were not formed. This was because the peduncle should have reached i t s maximum elongation a fte r the fr u it s had been fonned or a l l flowers aborted. I t was measured from the base to i t s peak.
The ränge and mean were found and recorded in centim etres.
The flo r a l parts were measured at flow er anthesis. The tepals, stamens and p i s t i l s were removed c a r e fu lly and th eir f u l l lengths were measured. The ranges and means o f each character fo r each species were determined and recorded in m illim etres
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P ollen Grains. The p ollen grains were dusted on clean glass slid e s from dehisced anthers. A drop o f 2fo acetocarmine stain was dropped and then ca re fu lly covered with clean co v erslip . The pollen grains were then measured at x40 o b je ctiv e o f a lig h t m icroscope. A unit o f the micrometre eyepiece graticu le equalled 2.5 microns at this m agnification. The micrometre units were then converted into microns.
The ränge and mdan fo r the length and width (o r diameters) were determined and recorded in microns.
The index o f each pollen was found by dividing the length by the width. The mean index and ränge were found and recorded.
E QUALITATIVE MOEPIIOLOGICAL CHARACTERS
Unlike the quantitative characters which were studied at plant maturity, q u a lita tive characters were studied right from the germination o f seed or sprouling o f new shoot to the end o f flow ering or fr u itin g . This was done so as to cover the whole l i f e cy cle o f each species in order to investigate whether any ch aracter(s) were due to stages o f development and/or seasonal variation s. Reoords were kept fo r at lea st twenty representatives o f each species (escept A. pubirhachis) . These reeords were then used in compiling the qu alitative characters as stated above.
The root structures fo r the plants were examined at d iffe r e n t stages o f development. The lo ca tio n o f the root tuber(s) and number per root were noted.
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-General Observations
Wie plante in th is complex have s ix tepal3; three large while the other three are r e la tiv e ly smaller in width. A carefu l Observa
tion o f the tepal arrangaaent reveals that most Chlorophytun species have the la rg e r tepals in the outer whorl while the smaller ones are in sid e. In the species o f Anthericum and Chlorophytum X, the smaller tepals are outside while the la rg er ones are in the inner whorl. These arrangements could have been a d ecisiv e separating f& ctor f o r the two genera, but £ . togoense has the two types o f arrangement.
The tepal d isp osition at the time o f p o llin a tio n is very in te r e s - tin g. In A. limosum. A . pterocaulon. A. pu birh ach is,
Chlo to phy tum X and £ . alism ifolium . the tepals spread out to the
base and la te r c lo s e up a fte r p o llin a tio n . I n t h e o t h e r s p e c i e s o f Chip ro phy tum, the flowers open and the tepals bend backwards to
expose the whole p i s t i l and stamens during p o llin a tio n . A fter p o llin a tio n , the tepals close up again. That i s , the open flow er is rtotate in Anthericum but ccjjnpanulate in Chlorophytum.
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RESULTS
The vegetative morphology o f representatives o f the sp eciss o f Antherieum and Chlorophytum in vestigated are presented in P lates I and II
Table 1 shows the le a f morphological data fo r ten Chlorophytum and three Antherieum taxa.
Table 2 contains some o f the data c o lle c te d from preserved
herbarium 3pecimens o f a l l known species o f the two genera in Nigeria, so as to highlight the p o ssib le usefulness o f le a f index and vein spacing in terva ls in these plants.
Talle 3 contain3 the root morphological data o f ten Chlorophytum and three Antherieum taxa.
Table 4 shows data fo r the reproductive shoot o f some representa
tiv e s o f both genera.
Table 5 gives the measurements o f the pollen grains in the plants handled.
Table 6 shows the summary o f the qu alita tive charactere f o r some species o f the two genera found in Nigeria.
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-FLAT'" I :
Photographs o f Anthericum speciea studied
A. A. limosum