Volume 86, Issue 5
November 1977, pages 275-336
pp 275-280 November 1977
A population ofCynodon dactylon (L.) Pers. from alkaline soil and one from normal soil were grown in replacement series on soil with various salts. The population from the alkaline soil was more competitive than the population from normal soil when grown on soil treated with salts. The reverse situation existed on normal soil. In a mosaic environment competition between the two ecotypes can occur in the field and could be important in their adaptation.
pp 281-286 November 1977
The nodal anatomy of 42 species belonging to 22 genera of Lamiaceae has been investigated. Two types of nodal configurations (1) unilacunar one-traced; (2) unilacunar two-traced have been reported. It is suggested that the unilacunar two-traced condition in this family is primitive and unilacunar one-traced condition has originated by approximation. This evidence has come from the unique nodal anatomy ofClinopodium umborosum where one leaf gets a single trace whereas the opposite leaf receives two traces. Variations in nodal pattern have been observed within the same species ofClinopodium umbrosum and in the different species ofMentha. Thus, Sinnott’s view that a major taxon has a specific type of nodal configuration does not have much significance in this family.
pp 287-294 November 1977
Many anatropous tenuinucellate and bitegmic ovules are present in the trilocular ovary ofIndotristicha ramosissima (Wight) van Royen andDalzellia zeylanica (Gardn.) Wight. The two integuments in both species originate simultaneously. The four nuclei present in the organized embryo sac are derived from the primary micropylar nucleus of the two nucleate embryo sac. Development and organization of the female gametophyte conforms to the Apinagia type, form B. The organized embryo sac has two synergids, an egg and a polar cell; there are no antipodal cells. Forms C and D of the Apinagia type do not exist in the family. Organization of the nucellar plasmodium occurs after fertilization.
pp 295-301 November 1977
Meiotic studies were reported inTrilobachne cookei (Stapf) Schenck ex Henr. for the first time. Chromosome number was found to ben=10. This is not in agreement with one of the earlier reports of 2n=10 but confirms the more recent report of 2n=20. Several hundred cells were examined at various stages of meiosis in many plants. Meiosis was regular, and pollen fertility and seed set were high. But irregularities like univalents, aneuploid numbers, quadrivalents, secondary association of bivalents into groups, interlocking of bivalents, pseudocytomixis, bridges, laggards and micronuclei were found in a low proportion of the cells. Two pairs of satellited chromosomes were present in the somatic metaphase plates. These facts taken together with the previous report of 2n=10 indicate the probable tetraploid nature of the present material. Intergeneric crosses attempted betweenTrilobachne and maize, teosinte, tripsacum and job’s tears (some of the other members of the tribe Maydeae) did not succeed.
pp 303-310 November 1977
Seed and seed coat development has been investigated inRhynchosia minima (Linn.) DC.,Cajanus cajan (L.) Millsp., andAtylosia platycarpa Benth. (tribe Phaseoleae, subtribe Cajaneae). The ovules are crassinucellate, bitegmic and campylotropous. The outer integument alone forms the seed coat, and consists of sclerenchymatous epidermis and hypodermis, middle zone of large, vacuolated cells and an inner zone of crushed parenchyma. Development of seed coat, structure of osteosclereids, presence of cavities in middle layers, along with other supporting characters of pericarp suggest that Cajaneae is a natural subtribe.
pp 311-321 November 1977
Location of esterases and nerve arrangement is studied inSinghiatrema longifurca andParadistomoides orientalis. Both the trematodes possess a pair of cerebral ganglia connected by cerebral commissure. From here three pairs of nerves proceed to anterior and posterior sides. Anterior pairs, interconnected by transverse commissures and connectives innervate the oral sucker and the anterior tip. Of the posterior pairs, ventrolaterals are well developed in both. InS. longifurca nervous organization is highly complicated with many branches.P. orientalis also sends a number of branches to various organs. Both parasites possess many presumptive neuro-secretory and sensory cells. Various degrees of esterase activity in both worms is located in excretory vesicle and ducts, suckers, genital pore, gonads, oviducts and eggs.
pp 323-327 November 1977
Investigations on the pattern of neurosecretion in the normal and aestivating specimens ofPila virens were carried out. Although secretory cells were found in all the ganglia examined they were absent in the connectives and commissures. No evidence for the presence of neurohaemal organs was obtained. With the onset of aestivation a decline in secretory activity was observed in all the ganglia. This change was quite pronounced in the pleuropedal and least significant in the visceral ganglion.
pp 329-336 November 1977
The bandicoots,Bandicota bengalensis (Gray), tend to favour a varied diet, but the foods offered are not selected in a linear order. Unextracted flours of millet and maize, are readily accepted: only semolina is equally accepted among the forms of ground wheat. Among whole cereals, millet is preferred but equally preferred is polished rice. Rice is also markedly preferred when boiled to its dry alternative. Foods mixed with sugar or groundnut oil are similarly favoured over plain alternatives.
Factors such as texture strongly influence the choice, while the effects of taste and calorific value are marked by their profound omnivory.
Mean rates of consumption vary according to choice, from 5 to 10% of body weight.