Some Aspects of Ontogeny of the Shoot Apices of Solanum melongena L. and Capsicum annuum L.

The ontogeny of the vegetative shoot apices of two importantvegetable plants, Solanum melongena L. and Capsicum annuum L.is described. Each shoot apex is studied at different stagesof seed germination. The relationship between time of germinationand (i) area of vacuoles in the cell, (ii) total area of thecell, (iii) area of the nucleus in the cell, and (iv) ratioof area of vacuoles in the cell to the total area of the cellin each apex is examined. The differentiation of cytohistologicalzonation in both apices is distinct only after one or two leavesare initiated and developed. At a certain stage heterogeneityin staining in the peripheral region of the shoot apex of S.melongena is found. The zonation in both plants differentiatesgradually in histological and cytological features. Vacuolationincreases or decreases in all the cells of the shoot apex orin the cells of a particular region of the shoot apex at differentstages of its ontogeny.     

Development, Histochemistry and Ultrastructure of Gum-resin Ducts in Commiphora mukul Engl.

Gum-resin ducts are present in the primary and secondary phloemof Commiphora mukul Engl. The important gum-resin, known commerciallyas ‘guggul’, is secreted and collected in ductswhich develop schizogenously. The duct initials have dense cytoplasm,large nuclei, increased cytoplasmic RNA and proteins. The lumenof newly-formed ducts widens accompanied by anticlinal divisionsand subsequent tangential elongation of epithelial cells. Histochemicaltests reveal that the epithelial cells have apparently largeamounts of proteins, cytoplasmic RNA, and DNA in the nucleus.Lipid globules are also present in these cells. Epithelial cellwalls in contact with the duct are thin and of a loose fibrillarmesh. Microtubules, randomly oriented in the epithelial cellsare always parallel and adjacent to the wall. The cytoplasmis rich in ribosomes, endoplasmic reticulum, mitochondria, plastidsand vacuoles containing osmiophilic substances. At the peripheralregion of the duct, electron-transparent bodies containing densely-stainedmaterial are present close to the tangential wall.     

Vascular Occlusions in the Stem of Ailanthus excelsa Roxb.

The stem of Ailanthus excelsa Roxb. (Simaroubaceae) may developvascular occlusions and gum-resin cavities in the xylem as aresponse to injury and infection. Fungal hyphae are observedin the vessel lumen and in the adjacent parenchyma cells. Theocclusions appeared in various forms and showed varying chemicalcomposition. The chemical nature of the occluding material differedfrom that of the exudate formed in the cavities. The majorityof occlusions contained lipids, protein, polysaccharides, phenolics,lignin and probably pectin, whereas, the exudate contained lipids,protein and four soluble sugars. All the components of the occlusionexcept lignin and pectin appear to have been formed in the parenchymacells adjacent to the vessel and migrated to vessel lumen throughthe vessel wall pits. The different constituents migrate intothe vessel lumen independently where they mix to form occlusions. Ailanthus excelsa Roxb., vascular occlusions, lignin, fluorescence, exudation     

Structure and Development of Stomata on the Vegetative and Floral Organs of Some Amaryllidaceae

The structure and development of stomata in 10 Amaryllidaceousmembers are described. The study is made on the leaves and floralorgans of Amaryllis belladona, Crinum asiaticum, C. bulbispermum,C. latifolium, C. pratense, Pancratium sp., Polianthes tuberosa,and Zephyranthes atamsco, and on leaves of Agave sp. and Curculigoorchioides. In most of the organs of the different plants studiedmore than one type of stoma occur, even on the same surface.However, the stomata are largely anomocytic in Amaryllis, Crinum,Pancratium, Polianthes, and Zephyranthes, but they are tetracyticin Agave and Curculigo. An increase in the number of subsidiarycells in teracytic, tricytic, paracytic, and stomata with onesubsidiary cell has been noted. It may be due to wall formationin the subsidiary cells or by the neighbouring perigenes assumingtheir form. The range of variation in different types of stomatain each organ has been studied. Abnormal features such as juxtaposedor superimposed contiguous stomata, connections between guardcells of nearby stomata, transformation of meristemoids intoepidermal cells are observed. The development of different typesof stomata in different organs of the same plant is perigenous.The systematic position of different genera is discussed inlight of the present findings. A method of preparing epidermalimprints by the use of Depex, a mounting medium, and white ofan egg is also described.     

Ultrastructure of Gum-resin Ducts in Cashew (Anacardium occidentale)

In Anacardium occidentale L., the gum-resin ducts in the primaryphloem of the stem develop schizogenously. Appearance of anintercellular space amongst the densely stained cells signalsthe initiation of a duct. During this process, the middle lamella,appears in places, as an electron-opaque area. The epitheialcells bordering the duct are oval and have convex inner tangentialwalls which are without any plasmodesmata, although they areabundant on radial and outer tangential walls. The cytoplasmof the epitheial cells is rich in rough endoplasmic reticulum(ER), free ribosomes, polysomes, mitochondria with swollen cristae,plastids with occasional osmiophilic inclusions, dictyosomesand vesicles. Osmiophilic material has been observed in thedilation of the cisternae of dictyosomes and also in vesicles.Sometimes, the osmiophilic material aggregates and forms largemembrane-bound globules. The globules fuse with the plasmalemmaat the inner tangential wall, and presumably the contents aredeposited in the space between the protoplast and the wall.This material passes through the loose matrix of the wall intothe duct. Some of the epitheial cells of the mature duct show‘dark’ cytoplasm, degraded organelles and occasionallyhigh vacuolation; ultimately they are lysed and their remainscollect in the duct. Anacardium occidentale L., cashew, gum-resin ducts, epithlial cell, dictyosome, osmiophilic material, ultrastructure     

Structure and Development of Stomata on the Vegetative and Floral Organs in Some Members of Caesalpiniaceae

The structure and development of stomata in 19 species of thefamily Caesalpiniaceae are described. The study is mostly confinedto the leaves, but observations have also been made on othervegetative and floral organs of some species Stomata may beparacytic, anisocytic, anomocytic, and with one subsidiary cell.Occasionally a stoma is diacytic, cyclocytic, or actinocytic.Different types occur individually or may be found side by sideeven on the same surface of an organ. The most prevalent typein all the genera is paracytic except in Caesalpima where itis anomocytic. The development of an anomocytic stoma is perigenous,but those with subsidiary cells are largely mesogenous; rarelyparacytic stomata are mesoperigenous. In spite of diversityof stomata, different types of stomata have similar patternsof development in different organs of the same plant. The presentinvestigation also indicates that the inconstancy of stomatain the family is due to (a) their diversity and (b) an increasein the number of subsidiary cells either by their division orby the neighbouring perigenes becoming subsidiary cell-like.     

Fatty Acid and Isoprenoid Quinone Composition in the classification of Bacteroides melaninogenicus and Related Taxa

Aerobic deterioration of lucerne, maize and wheat silages was characterized by rapid increases in yeast and mould flora which oxidized lactic and volatile acids resulting in increased temperature and pH. While populations of yeasts and moulds were similar, temperature increases were slightly greater for silages inoculated with Lactobacillus acidophilus and Candida spp. After 48 h the pH of the inoculated silages was higher in general and concentrations of acids were lower than controls. Bacterial growth was slight although continued lactic acid production was probable. In contrast to lucerne and maize silages, the pH of wheat silage remained stable during this period because of high butyric levels, but temperature and yeast populations increased. After 48 h the pH rose above 5 in maize and lucerne, and bacterial growth and metabolic activity resumed resulting in volatile and non-volatile acid production from carbohydrate fermentation and deamination of amino acids. During this phase of aerobic deterioration yeast growth slowed or stopped, but temperatures remained high and pH continued to climb probably because of production of ammonia. The changes in gross composition of the silages did not follow any particular pattern. Losses in dry matter were small (2.5–4.0%) and changes in individual components probably reflect this loss rather than substantial changes. Protein availability in the lucerne silages undoubtedly decreased, as protein losses were high. It is concluded that the aerobic deterioration of silage is enhanced by the addition of L. acidophilus and Candida spp. at ensiling.     

Studies in Stomata of Chilli and Brinjal

Ontogeny and development of stomata in chilli (Capsicum annuumL.) and brinjal (Solanum melongena L ) are described Paracytic,anomocytic, and anisocyuc stomata are present Abnormalitiessuch as stoma with a single guard cell and degenerated stomatalcells are common. Degeneration of guard cell is traced in chilliJuxtaposed, superposed, and obliquely placed contiguous stomataare described. An incompletely differentiated menstemoid wasfound contiguous with a normal stoma Rarely a guard cell dividesto form a menstemoid. Cytoplasmic connections between the guardcells of adjacent or juxtaposed contiguous stomata are observedin chilli Extruded nucleoh in the guard cells of chilli arecommon Extruded nucleoh may enlarge The wounded epidermis ofchilli lose sinuosity of their walls and the degeneration ofguard cells is common.     

Ontogeny of Tendrils in Antigonon leptopus H. & Arn.

In Antigonon leptopus the main tendrillar and axillary branchis a modified inflorescence axis. It usually bears 6–7lateral bracts out of which 3–4 lower ones are small andleaf-like while the upper 2–3 are tendrillar; 2–3tendrils are also present at its terminal end. The vegetativeshoot apex shows a single layer of tunica and an inner massof corpus without any cytohistological zonation. The earliestaxillary bud or tendril meristem arises at the second node andit elongates due to rib meristem activity. The bract primordiaarise in an acropetal succession. The initiation of the bract-tendriland the leafy bract is similar. In the development of the bract-tendril,marginal meristem activity is absent or reduced and the differentiationof the apical and subapical initials is absent. The terminalbract-tendrils arise as lateral appendages and the residuumof the apical meristem of the main axillary tendril persistsfor some time. In the flowering period the floral buds arisein the axils of the bracts and bract-tendrils. No flowers arepresent in the axils of terminal bract-tendrils.