An Absolute Review on Oxalis corniculata Linn. - International ...

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International Journal of Research in Pharmaceutical and Biomedical Sciences ISSN: 2229-3701 manual hoeing), two types of weeding on inter-row (with or without manual hoeing), and four nitrogen levels applied after planting (00, 60, 90, and 120 kg yield at harvesting. Plants and first ear insertion height were affected when nitrogen fertilizer was not applied. Treatments without weed control showed that weed interfered negatively with plants height. There were no correlation between weeds and nitrogen fertilizer for all parameters evaluated. Parcels without weed howed the highest ear weights and final grain production. Treatments that received nitrogen fertilizer, independently of studied arrangement, provided higher yields 47 . Oca (Oxalis tuberosa Mol.) is an under-utilized tuber crop from the <strong>An</strong>dean region. A protocol for the cryopreservation of in vitro grown shoots has been developed using the vitrification solution PVS2. Two genotypes were studied (G1 and G27). Nodal segments were cultured on MS medium and incubated at 10 degree C with 16 h photoperiod and 10 mol per square meter per second irradiance, for two weeks. Apices were then excised and cultured on MS+0.15 M sucrose for 3 days at 5 degree C in darkness. Subsequently, apices were immersed in a loading solution (liquid MS medium+2 M glycerol+0.4 M sucrose), and then treated with the vitrification solution PVS2 for 0 to 40 minutes. Cryovials were then immersed in liquid nitrogen. Four weeks after rewarming and culture on recovery medium, genotype G1 showed approximately 60 percent recoveries (normal growth) with 20 min PVS2 treatment. Genotype G27 showed lower recovery (30 percent). Differential scanning calorimetry yielded a TG midpoint for PSV2 solution of ca. -120 degree C. Calorimetric studies on apices at different stages of the cryopreservation protocol showed a change in calorimetric parameters consistent with a decrease in the amount of frozen water as the protocol advanced 48 . ECOLOGY Changes in plant affinity to communities of different types are viewed by the example of the North- European forest studied in 1993-2001. Species occurring near their range limits prefer habitats with smoothed amplitudes of minimum factors ("the law of preference for non-varying environments"). That's why Oxalis acetosella and other boreal-nemoral species demonstrate affinity to riparian forests of the middle-boreal. Plant dispersal could be rather fast in the course of the corresponding primary succession following the glacier retreat or the marine retrogression (the "impulse" hypothesis). Since the climax pattern is established running waters and disturbed lands serve as "migration channels" for plant 49 . The reproductive components of plant invaders have mostly been studied in species reproducing sexually but little is known about invaders that depend exclusively on vegetative reproduction. In this paper, the importance of the different recruitment stages on population growth is quantified and, thus, the invasion potential of the South African annual geophytes Oxalis pes-caprae invading Mediterranean ecosystems is assessed .Oxalis pes-caprae has a transient bulb bank that remains dormant in the soil during summer. High levels of bulb predation after dispersal, followed by bulb mortality during summer or a failure to germinate in autumn were the most critical factors limiting plant establishment. Bulb germination was high. However, plant establishment and bulb production is constrained by intraspecific competition, but is not affected by soil disturbance. No symptoms of spatial discordance could be found between recruitment stages because the spatial variability of the life cycle was extremely low at all the scales examined (i.e. among populations, habitats and microsites). It was estimated that, on average, 4 % of bulbs can become plants the following year and the field rate of population increase (lambda) to be 0.08. The results suggest that invasion is constrained by post-dispersal bulb predation, loss of viability of the propagule bank due to summer drought and high intraspecific competition. However, a high spatial concordance between recruitment stages and probably a high propagule pressure due to human and livestock bulb dispersal determine the success of this invader across Menorca Island 50 . There are two large oil shale fueled power plants, Baltic PP and Estonian PP. On burning oil shale the main atmospheric pollutants are fly ash, sulphur oxides and nitrogen oxides. The radial increment was measured and concentrations of Ca and Cu were estimated in the stemwood of Scots pine (Pinus sylvestris L.) from four sites in the influence area of the Narva power plants. Increment cores were taken also from two sites in an unpolluted area located 112 and 120 km northwest from the Estonian PP. The stands selected for investigation were similar as to their edaphic conditions and forest survey indicators (75- to 80-year-old (Oxalis-) Myrtillus-type pine stands of 0.7-0.8 density and of quality class II). The strongest effect of air pollution on radial increment was observed on the sampling site in the direction of dominating winds at a distance of 22 km to northeast from the Estonian PP. Using the annual rings, the core samples were divided into five-year sections (1945-1949; 1950-1954 etc.). The concentration of Ca increased and that of Cu decreased from the youngest, outermost annual rings towards the centre of the stem 51 . The cavermiculatus andinus n.sp.is described and illustrated from Oxalis tuberose Vol. 3 (3) Jul – Sep2012 www.ijrpbsonline.com 1182
International Journal of Research in Pharmaceutical and Biomedical Sciences ISSN: 2229-3701 originally collected in the vicinity of Lake Titicaca high in the <strong>An</strong>des mountains of southern Peru. This new species differs markedly front the other two species in the genus, especially in having a much greater female vulval-anal distance and annules with lined punctation on most of the female body with a lacelike pattern restricted to the posterior portion, particularly at the vulva and anus which do not protrude. Females are essentially spherical with protruding neck, white to yellowish in color, and can easily be mistaken for potato cyst nematodes 52 . ANTIMICROBIAL ACTIVITIES A new type of nitrogen-fixing, oxalate-oxidizing Azospirillum sp. was isolated from the roots of Oxalis pes-caprae. Polyphasic taxonomy was performed, including auxanography using API galleries, physiological tests and 16S rRNA sequence comparison. Optimum growth occurred at 30 degrees C, pH 7.5. Growth was observed at 37 and 42 degrees C with oxalate and in the presence of 3-4% NaCl and 2% potassium oxalate. In liquid culture, the doubling time (t(d)) with oxalate was 9 h. Its closest phylogenetic neighbors, as deduced by 16S rDNAbased analysis, were Azospirillum brasilense, Azospirillum doebereinerae and Azospirillum lipoferum, with 99.5, 98.4 and 96.7% sequence similarity, respectively. The strain differed from A. brasilense by its ability to use N-acetylglucosamine, D-glucose and D-mannitol. It may be a variant strain of A. brasilense. Oxalotrophic, N2-fixing species of the genus Azospirillum may be important contributors to soil formation, soil fertility, and retention and/or cycling of elements necessary for plant growth 53 . GENETICS & BIODIVERSITY The <strong>An</strong>dean tuber-bearing species, Oxalis tuberosa Mol., is a vegetatively propagated crop cultivated in the uplands of the <strong>An</strong>des. Its genetic diversity was investigated in the present study using the intersimple sequence repeat (ISSR) technique. Thirty-two accessions originating from South America (Argentina, Bolivia, Chile, and Peru) and maintained in vitro were chosen to represent the ogeographic diversity of its cultivation area. Twenty-two primers were tested and 9 were selected according to fingerprinting quality and reproducibility. Genetic diversity analysis was performed with 90 markers. Jaccard's genetic distance between accessions ranged from 0 to 0.49 with an average of 0.28 +/- 0.08 (mean +/- SD). Dendrogram (UPGMA (unweighted pairgroup method with arithmetic averaging)) and factorial correspondence analysis (FCA) showed that the genetic structure was influenced by the collection site. The two most distant clusters contained all of the Peruvian accessions, one from Bolivia, and none from Argentina or Chile. <strong>An</strong>alysis by country revealed that Peru presented the greatest genetic distances from the other countries and possessed the highest intra-country genetic distance (0.30 +/- 0.08). This suggests that the Peruvian oca accessions form a distinct genetic group. The relatively low level of genetic diversity in the oca species may be related to its predominating reproduction strategy, i.e., vegetative propagation. The extent and structure of the genetic diversity of the species detailed here should help the establishment of conservation strategies 54 . Thirty-four Glomeromycota taxa (small-subunit ribosomal RNA gene (SSU rDNA) sequence groups) were detected from 90 root samples (911 clones), including eight new taxa. Sequence groups related to Glomus intraradices were most common (MO-G3 and MO-G13). Samples of H. nobilis were colonized by more AM fungal taxa (3.68 +/- 0.31) than those of O. acetosella (2.69 +/- 0.34), but did not differ significantly in this respect from those of F. vesca (3.15 +/- 0.38). Effects of forest management, host plant species (except above) or season on the number or composition of fungal taxa in root samples were not detected, and neither were they explained by environmental variables (vegetation, soil and light conditions). * This is the most taxon-rich habitat described to date in terms of root-colonizing Glomeromycota. The data demonstrate the importance of temperate coniferous forests as habitats for AM fungi and plants. Lack of obvious fungal community patterns suggests more complex effects of biotic and abiotic factors, and possibly no adverse effect of common forest management practices on AM fungal diversity 55 . Eleven Oxalis L. species from the province of Buenos Aires (Argentina) were investigated with scanning and transmission electron microscopes. Researchers identified four different types and two subtypes of orbicules and conclude that the close morphological similarity between these species is also reflected in their orbicules, and also suggest that the orbicules morphology may be a useful character in systematic studies 56 . Assessments of mycorrhizal colonization (percent root length, intraradical structures) were made by washing and staining the roots. Soil samples of each plant species were pooled and subsamples were obtained to determine AM spore numbers. The herbaceous species formed both Arum- and Paristype morphologies, whereas the tree and the shrub species formed respectively single structural types of Arum- and Paris-type. AM colonization, intraradical fungi structures and AMF spore numbers displayed variation in species, seasons and sites. D. indica Vol. 3 (3) Jul – Sep2012 www.ijrpbsonline.com 1183
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