|Published (Last):||23 March 2012|
|PDF File Size:||7.84 Mb|
|ePub File Size:||12.9 Mb|
|Price:||Free* [*Free Regsitration Required]|
The ergastic substances of 93 angiospermous seed samples belonging to the family Fabaceae have been investigated. Forty four and 86 of the samples indicated positive for alkaloid and fats and oil respectively while 34 samples indicated the presence of protein and tannins. The morphological characteristics of starch grains i. Of the 93 seed samples 27 are found to contain starch grain. However, the starch grains are restricted mainly to the herbaceous habit. In general arborescent taxa either lack starch grains or such grains are of sparing occurrence.
The ergastic substances are secondary products of plant metabolism, which might have been formed at certain stages of metabolic process and are retained when the taxon in question underwent further evolution Erdtman, Since seed is the storage organ of ergastic materials such as alevrone grains and starch grains and these stored materials are of taxonomic value, protein bodies, alkaloids and oil and fat bodies are of limited systematic value.
However, the shape, size and percentages of different types of starch grains are of great systematic value as demonstrated by Tatteoka and in the family Poaceae. Harz was the pioneer in the recognition of the taxonomic value of starch grains. Hackel and Reichert used the starch grain characteristics in the delimitation of genera and species in the family Poaceae.
A comparative study of the structure of starch grains and the type of striations is of great significance in determining the identity of taxa, especially when starch is used as an adulterant in commercial flour.
Attempts have been made by different workers at elucidating the chemical composition of plants belonging to different families Nwachukwu and Edeoga, and data from such investigation suggest that thorough survey of different taxonomic groups might give results of taxonomic significance as earlier expressed by Hilditch The present research is a part of ongoing project on the nature of ergastic substances in angiospermic seeds.
The earlier contributions on this project are Gill and Ayodele , Gill et al. The results of the survey of 93 Fabaceae seeds for ergastic substances are reported here. This study was carried out in Chemical tests of various ergastic substances were carried out following methods used by Idu and Gill The results of the taxa studied for their ergastic substances according to their life forms trees, herbs and shrubs have been summarized in Table 1 - 3 respectively.
The morphological characters of starch grain of 27 species of Fabaceae are summarized in Table 4 - 6 according to their life forms. For about four decades now, much attention has been focused on the comparative studies of basic molecules in relation to taxonomic problems. De-Wet and Scott are of the opinion that essential oil can be used as a taxonomic criterion and according to them, chemical characters are often found to be more reliable than the gross morphology in determining the taxonomic affinities.
Several researchers, Bate-Smith and Metcalfe , Gill et al. From the present survey of 93 seed samples of Fabaceae, 46 taxa were herbaceous and 47 ligneous.
Of these, alkaloid was found to be present in 44 taxa; 25 taxa are herbaceous and 19 ligneous. Gill and Abili reported the occurrence of alkaloids in of the angiospermic seeds they investigated and Gill et al.
They also reported the absence of alkaloids in the seeds of members of the family Agavaceae, Caricaceae, Cornaceae and Limnatheceae. Fats and Oil have been observed in all the presently investigated taxa except the following species Acacia albida , A. Out of the 86 taxa reported here to contain Fats and Oil, 44 are herbaceous and 42 are ligneous. Gill and Abili in their survey of ergastic substances of angiospermic seeds reported the occurrence of Fats and Oil in all the taxa except Pertya sinensis Asteraceae.
De-Wet and Scott are of the opinion that essential oils can be used as a taxonomic criterion and according to the chemical characters are often found to be more reliable than the gross morphology in determining the taxonomic affinities. Proteins have been observed in the seeds of Fabaceae investigated except in Astragalus cicer , A.
Tannins on the other hand have been recorded in 34 taxa of which 18 are herbaceous and 16 ligneous. Bete-Smith and Metcalfe demonstrated the importance of tannins as a taxonomic character and according to them, there tend to be a parallelism between the occurrence of tannins and phylogenetic status of the family in which they occur. The lack of tannins is often more marked in herbaceous than woody plants. In other words, the presence of tannins in a taxon is a primitive character and gets lost with increasing phylogenetic specialization.
Earlier, Gill and Abili reported the occurrence of starch grains in 17 out of taxa they investigated. During the present study, starch grains have been recorded only in 27 taxa. It is interesting to note that 19 taxa containing starch grain are of herbaceous habit and only 8 ligneous. Also, simple starch grains have been recorded in all except Crotalaris ochrolenca , Stizolobium deeringianum , Vigna mungo and V. The shapes of starch grains in the majority of taxa investigated were circular, predominantly, followed by irregular and oblong shape grains.
Gill et al. The size of starch grains in variable from the smallest 6. The helium and striation were predominantly distinct. Apparently, there is no correlation between starch grains characteristics and phylogenetic position of the taxa investigated. Similar results had earlier been reported by Gill and Abili and Gill et al. Theoretically, compound starch grains are expected to be in herbaceous taxa, which was so during this study, while simple starch grains were found in ligneous taxa.
The shape of starch grains where observed not to reflect the phylogenetic position of the taxa as circular starch grains were found more in woody taxa while irregular and other shapes of starch grains were observed among the herbaceous taxa. Therefore, the occurrence of starch grains, shape and size does not reflect the phylogenetic position of the taxa in which they are found. Further, Gill and Ayodele and Gill et al. According to these workers, starch grains are generally associated with herbaceous habit and the results of the present investigation confirm this hypothesis.
However, the relationship between the occurrence of starch grain and life form does not hold for the family Asteraceae Omoigui and Gill, ; Idu and Gill, , The foregoing account proves the utility of the nature of ergastic substances in the field of systematics and this has been comprehensively reviewed by Bate-Smith and Boulter et al.
From the foregoing discussion, it is apparent that the plant seeds showing the presence of proteins and fats and oil could be qualitatively analyzed and this needs further investigation.
Those showing suitable quantities of fat and oil and proteins palatable for human consumption could be commercially exploited. The taxa, which gave positive test for alkaloids and tannins, need further investigation for possible exploitation in the pharmaceutical and leather industries. Subscribe Today. Science Alert. All Rights Reserved. Research Article. Idu and H. Similar Articles in this Journal. Search in Google Scholar. How to cite this article: M. Onyibe , Research Journal of Botany, 3: DOI: Table The morphological characteristics of starch grain of some species of Fabaceae.
Bate-Smith, E. Metcalfe, Leuco-anthocyanius 3. The nature and systematic distribution of tannins in dicotyledonous plants.
Chemical approach to plant taxonomy. Low Temp. Boulter, D. Derbyshire, J. Fralim-Lenteles and R. Polhills, Observations on the cytology and seed proteins of various African species of Crotolaria L. New Phytol. De-Wet, J. Scott, Essential oils as taxonomic criteria. Bothriochloa Bot. Erdtman, H. Flavonoid heartwood constituents of conifers. Dublin, Gill, L. Ayodele, On the nature of ergastic substances in the seeds of some tropical and temporate angiosperms.
Plant Anat. Idu, On the nature of ergastic substances in some Caryophyllaceae seeds-IX. Applied Sci. Abili, Nature of ergastic substances in some angiospermic seeds-V. Feddes Rep. Olabanji and S.
Phytochemical constituents are distributed in various parts of plants and their localization is indicative of their therapeutic properties. Ergastic crystals such as calcium oxalate crystals are also found in almost all plant parts, which is an anti—nutrient as the dietary oxalates contributes to human ailments. Several of the medicinally useful plants contain these crystals and consumption of such plant materials in raw form can cause health problems in humans. Ergastic crystals can be an important diagnostic tool for the identification of raw drug as in Costus pictus a medicinal spiral ginger commonly called Insulin plant is devoid of cuboidal crystal but its related Costus speciosus leaves possess characteristic cuboidal shaped crystal in its leaf mesophyll.
Ergastic Crystal Studies for Raw Drug Analysis
Ergastic substances are non- protoplasm materials that one can find in cells. These are usually products of metabolism. Ergastic substances include crystals , oil drops, gums , tannins , resins and other compounds. Some of these substances help the organism function, keep up cell structure, or are just stored food material such as oil or fat. During the life of a cell, they can appear and disappear. Ergastic substances may appear in the protoplasm , in vacuoles , or in the cell wall.
Nature of Ergastic Substances in Some Fabaceae Seeds
Ergastic substances are non- protoplasmic materials found in cells. The living protoplasm of a cell is sometimes called the bioplasm and distinct from the ergastic substances of the cell. The latter are usually organic or inorganic substances that are products of metabolism, and include crystals, oil drops, gums, tannins , resins and other compounds that can aid the organism in defense, maintenance of cellular structure, or just substance storage. Ergastic substances may appear in the protoplasm , in vacuoles , or in the cell wall. Reserve carbohydrate of plants are the derivatives of the end products of photosynthesis.