Radiation-induced Organogenesis and Isoenzyme Patterns in Long-term Callus Cultures of Datura innoxia

Effect of gamma irradiation on growth, shoot organogenesis andenzyme activities and isoenzyme patterns of -amylase and peroxidaseduring differentiation in long-term calluses of Datura innoxiahave been investigated. Radiation in doses of 0.2 and 1.0 kRstimulated the shoot regeneration frequency as well as the numberof shoots per regenerating callus. The 0.2 kR dose could induceshoot organogenesis even in calluses incubated in the dark oncallusing medium, although with less frequency. Such cultures,however, showed profuse shoot regeneration when sub-culturedonto regeneration medium under light conditions. A higher radiationdose (5.0 kR) was lethal to both growth and shoot differentiation.Prior to shoot regeneration, -amylase and peroxidase specificactivities increased to four- to fivefold and 7–24-fold,respectively. While the amylase isoenzyme pattern remained unchanged,specific changes in the isoperoxidase pattern were observedduring shoot differentiation in callus cultures. The most significantchange was the appearance of fast-moving anodic bands priorto visible shoot differentiation. Thus, such isoperoxidasesprovide useful biochemical markers for shoot differentiation. Datura innoxia, shoot organogenesis, isoenzyme pattern, gamma-radiation, growth regulators     

Phosphorus-containing Compounds at Comparable Germination Stages of Caryopses of Avena Species

A number of the phosphorus transformations accompanying imbibitionand initial germination in caryopses of wild oats (A vena fatuaL.) differ in nature and kind from those accompanying seedlingdevelopment. Even in non-dormant lines of wild oat germinationis extended and seedling development uneven. The significanceof early phosphorus transformations can be obscured. Proceduresto synchronize germination stages were developed by (i) usingseeds which had been exposed to room temperature for extendedperiods of dry storage, (ii) inducing germination of imbibedseeds by dehulling, piercing and/or gibberellin A3 treatments,or (iii) constructing artificial seed groupings of known germinationpercentage by appropriate selection of seeds from an unevenlygerminating seed source. All three procedures were effectivein identifying those processes associated with initial germination.The best synchronization was obtained with method (i). Germination,in contrast to imbibition, was signalled by a significant dropin inorganic phosphate levels, followed by a later rise as seedreserves of phytate were mobilized for seedling development.Differences in the rates of mobilization of acid-soluble phosphoruscompounds were apparent between cultivated oats and geneticallynon-dormant wild oats. Key words: Avena sp, Phosphorus compounds, Seeds, Germination     

ATP Synthesis during Water Imbibition in Caryopses of Genetically Dormant and Non-dormant Lines of Wild Oat (Avena fatua L.)

Levels of ATP in dry caryopses of wild oats (Avena fatua L.)were much lower than in imbibed seeds of the seven geneticallypure lines surveyed. The ATP content of the lines with highgenetic dormancy was consistently lower than the ATP contentof genetically non-dormant lines, but no significant correlationwith depth of dormancy was found apart from this. Massive increasesin ATP content occurred within 30 min of water uptake by caryopsesof both dormant and non-dormant lines. The synthetic pathwaystudied utilized inorganic phosphate with great avidity to formATP. The ability to form ATP upon imbibition was present inboth embryo and de-embryonated caryopsis. The ATP levels attainedin imbibing caryopses appeared sufficient to support considerablesynthetic activity, and this reduced the possibility that adeficiency in ATP was responsible for the maintenance of dormancyin such imbibed seeds. The low levels of inorganic phosphatein the embryos of genetically dormant lines of wild oat couldrepresent a limiting factor, if the active formation of ATPupon water imbibition resulted in a scarcity of phosphate forother reactions essential to germination. Key words: Avena fatua, ATP synthesis, Inorganic phosphorus, Seed dormancy, Germination, Water uptake     

Effect of Glucose and Auxins in Rooting Etiolated Stem Segments of Populus nigra

2.5 cm long stem segments of Populus nigra L. did not root when cultured in water or in auxins alone but rooted in glucose. The number of rooted segments and roots produced on them increased with rising glucose concentrations up to 0.5%, but decreased with higher concentrations. An addition of 1.0 mg/1 IAA inhibited rooting at 0.01 % glucose, was ineffective at 0.1 % and stimulative at higher concentrations of glucose which were inhibitory when used alone. The results show that the auxin effects on rooting are influenced by the nutritional status of the stem cutting of a species, and that a proper balance of the two is necessary for root development.     

Light and ethylenediamine tetraacetic acid mediated differential effects of ammonium on nitrate reductase activity in maize seedlings

Abstract Effect of ammonium on in vivo activity of nitrate reductase in roots, shoots and leaves of maize (Zea mays L.) seedlings was studied in relation to light/dark conditions and EDTA supply. Supply of 5 mM (NH₄)₂SO₄ increased the steady state level of enzyme only in leaves and in light, while it had no effect in roots and shoots and in the dark. The substrate induction of enzyme was also little affected by 1 to 10 mM (NH₄)₂SO₄ in roots and shoots. In the leaves the activity in the dark was either inhibited (minus EDTA) or stimulated (plus EDTA) by 5 to 10 mM (NH₄)₂SO₄. The activity was stimulated in the light also in the presence of EDTA at higher concentrations of ammonium. When different concentrations of ammonium were supplied without any exogenous nitrate in the light, the enzyme activity increased at low concentration and was either inhibited or unaffected at higher concentrations depending upon the tissue used. Supply of EDTA with ammonium modified its effect to some extent. It is suggested that the effect of ammonium on nitrate reductase activity depends upon the tissue used and the effective concentration of the ammonium.     

Floral development of Justicia gendarussa (Acanthaceae)

The sequence of primordial initiation is acropetal and the primordia develop in the same order in which they appear. The floral apex has a two-layered tunica in all stages of development. There is no significant difference in the initiation of any of the floral appendages and thus all floral organs are homologous with respect to their histogenetic origin. The short calyx tube is formed by ontogenetic fusion of the bases of sepals; but the corolla tube arises partly by ontogenetic union of originally free parts and partly by zonal or intercalary growth. Each primordium receives a single procambium strand shortly after its initiation, except those of the posterior pair of stamens, which do not receive any vascular supply. This provides another example which goes against the doctrine of "conservatism of vascular bundles". The placentation in Justicia is parietal ontogenetically as well as anatomically.     

Cytology of collagenous spherulosis of the breast: a diagnostic dilemma – report of three cases

Collagenous spherulosis is a rare incidental finding seen in association with benign breast lesions. Cytological findings in three cases of collagenous spherulosis diagnosed on fine needle aspiration are presented. The presence of hyaline pink globules surrounded by benign myoepithelial cells in Giemsa stained smears was a diagnostic feature. Associated lesions were atypical papillary hyperplasia (2) and fibroadenoma (1). Adenoid cystic carcinoma was the close differential diagnosis on cytology. Awareness of this entity is important to avoid a false positive diagnosis of malignancy.     

Morphology and development of the reproductive shoots of Lilaea scilloides (Poir.) Hauman (Alismatidae)

Shoots of adult plants of Lilaea scilloides have a sympodial form. Each unit of the sympodium bears a single sheathing prophyll (which is the only kind of foliage leaf produced in the adult) and terminates in an inflorescence. The prophyll subtends the next unit of the sympodium. A further accessory bud can form in association with each unit. This bud repeats the pattern of the main sympodium, giving the plant a tufted habit. Five different kinds of flower can be identified in the inflorescence: a unisexual male flower with a single perianth member and adnate stamen; a bisexual flower, with a single perianth member and adnate stamen, and a single carpel with an anatropous bitegmic ovule; a unisexual female flower with a single perianth member and carpel; a unisexual female flower comprising only a single carpel; and a female flower comprising only a single carpel with a very long filamentous style. The first four kinds occur in the upper part of the inflorescence which is normally elevated on a scape, while the last kind is restricted to the base of the inflorescence. In the position of the basal flowers several variations have been observed in cultivated material. These include branching associated with the basal flowers, which results in the development of additional basal flowers or inflorescences, and even total replacement of a basal flower by an inflorescence or a branching structure bearing flowers. A review of past literature includes a clarification of some persistent errors which have confused the taxonomic position of the plant and the morphological interpretation of the reproductive appendages.