Stage Of Secondary Development Research Articles

ARTICLE WOODY SPECIES STRUCTURE AND REGENERATION STATUS IN MEHAL WONZ - ZEGO FOREST, N/ SHEWA ZONE, AMHARA REGIONAL STATE, ETHIOPIA

This study was conducted on Mehalwonze- Zego forest in North Shewa zone, Amhara Regional State, Ethiopia, A Transect sampling method was used to collect vegetation data. Sixty seven(67) plots of 20m × 20m were laied each at 300m intervals and five subplots of 2m × 2m, one in the center and four in the corner of the main plots, were laid for seedling and sapling inventory. Vegetation parameters such as DBH >2.5cm, H ≥2.5m of as well as seedling and sapling density with five sub plots of 2m × 2m. A total of 55 woody species belonging to 51 genera and 38 families were identified. The density of seedlings, saplings and matured woody plants in all of the plots were 1302, 1517 and 905 individuals, respectively. Importance Value Index (IVI) of each species were calculated, based on this value the conservation priority classes was done which indicated that there are woody species that require urgent conservation. The total basal area of the forest was 67.96 m2/ha. DBH and height class distribution of woody spcies confirms that the forest is under a secondary stage of development. Based on the results of regeneration assessment, conservation priority should be given for species with poor regeneration status.

Floristic Composition, Structure, and Regeneration Status of Woody Plants in Wonjeta St Micheal Church Forest, Northwestern Ethiopia.

The study was conducted in a historian Wonjeta St Michael Church Forest, believed to be constructed in 11th century in Northwestern Ethiopia. The composition, structure, and management of this forest is not documented. Fifty plots of 20 m × 20 m (400 m2) were laid along five-line transect for vegetation data collection. In addition, 5 m × 5 m subplots were laid within the main plot to sample seedlings and saplings. All plots were laid at a distance of 50 m along the transect lines. The diversity and population structure of woody individuals of trees and shrubs with a diameter at breast height (DBH) ≥ 2.5 cm and height ≥2 m were measured, and DBH <2.5 cm and height <2 m were counted as seedlings and saplings. All trees and shrubs recorded in the 50 plots were used for vegetation structure analysis. A total of 65 woody plant species in 53 genera and 33 families were recorded. Out of the total number of species, three were found to be endemic to Ethiopia. The family Fabaceae had the highest number of species, followed by Moraceae, and then Euphorbiaceae with 14, 6, and 4 species, respectively. The results of Shannon Wiener diversity and evenness indices of woody species were 2.8 and 0.68, respectively. Woody species densities for mature individuals were 2,202.5 stems ha-1, seedling 2419.2 stems ha-1, and sapling 1737.6 stems ha-1. Priority for conservation should be given using population structure, important value index, and regeneration status as criteria. Results of the structural analysis revealed that the Forest is highly dominated by small-sized trees and shrubs indicating that it is in the stage of secondary development and there are species that require urgent conservation measures.

Woody Species Diversity, Composition, and Regeneration Status of Abbo Sacred Forest, Southern Ethiopia.

This study was conducted in Abbo Sacred Forest in Wonsho district, Sidama Zone of Southern Nations, Nationalities, and People's Region (SNNPR), southern Ethiopia, to investigate the woody species diversity, vegetation structure, and regeneration status of the forest. A systematic sampling design was employed to collect vegetation data. Sixty quadrats of 20 m × 20 m were laid at every 200 m interval between each quadrat and 400 m apart between each line transect following the altitudinal gradient. Quadrats of 20 m × 20 m were used to record DBH and the height of all woody plant species reaching a height of ≥2 m and a DBH of ≥2 cm. For the inventory of seedlings and saplings, five subplots of 2 m × 2 m, one at the center and the other four on each corner of the main quadrat, were used. DBH, height, seedling, and sapling density of woody species were recorded in each quadrat. The data were analyzed by using Shannon-Wiener diversity and equitability indices, and the structural analysis was carried out based on frequency, density, DBH, height, and basal area/ha-1. The importance value index was also computed. Regeneration status was computed by comparing the density data of saplings and seedlings with those of mature trees. A total of 63 woody species belonging to 56 genera and 35 families were identified. Three endemic species to Ethiopia were recorded. Analysis of selected woody species showed diverse population structures. The findings of this study revealed that small trees and shrubs dominated the forest, suggesting its status under a secondary stage of development. Some woody species require urgent conservation measures. Therefore, local and regional stakeholders should integrate and work together to develop and implement sound conservation and management strategies that encourage the sustainable utilization of forest resources.

Floristic Composition, Vegetation Structure and Regeneration Statues of Woody Plant Species of Sheleko Medihanialem State Forest in Fogera District, Ethiopia

This study was conducted in Shelekomedihanialem state forest in Fogera district, South Gondar Zone, Ethiopia, to identify the floristic composition, vegetation structure,diversity and regeneration status of the woody plant species. Systematic sampling method was used to collect vegetation data from 5 transect lines 200m far apart and 50(20m x20m) quadrates at distance of 100m. To collect data for seedling and sapling, five 1m x 1m sub-plots were laid in each of the main plot, where four were at the corners and one at the center. Diameter at breast height was measured DBH ≥2.5cm while height was≥2m.Shannon-WiennerDiversity Index was used to calculate species diversity, richness and evenness. The densities of mature, sapling and seedling of woody plant species were 2055.5,2240 and 2400.5 individuals/ha respectively and the basal area of the forest was 2.246 m 2 /ha.The result of vegetation structure of woody plant species and regeneration status analysis in the forest revealed that the forest was dominated by small-sized trees and shrubs indicating that it is in the stage of secondary development. Finally, this study indicated that the population structure of the most woody plant species in Shelekomedihanialem state forest is in a good status of regeneration recruitment level. From the point of view of managing forests for the sake of biodiversity conservation, if appropriate management measures are taken, the nature of the population structure of most of tree species could be improved. K e ywords : Ethiopia, Floristic composition, regeneration, Forest, vegetation structure DOI: 10.7176/JBAH/12-5-02 Publication date: March 31 st 2022

Heat stress impairs in vitro development of preantral follicles of cattle

Although detrimental effects of heat stress on antral follicle development have been well studied, long-term effects - affecting the preantral follicle pool – are still largely unknown. The goal of this study was to evaluate effects of heat stress on growth, viability, gene expression and ATP production of preantral follicles of cattle. Follicles at the primary, early secondary and secondary stages were isolated from cattle ovaries and individually cultured while imposing physiological (CON; 38.5 °C) or intermittent heat stress (HS; 38.5 °C for 16 h and 41 °C for 8 h daily) conditions for 7 days. Individual follicles were subjected to real-time qPCR for determination of relative abundance of BAX, HSPA1A and SOD1 mRNA transcripts and evaluated for ATP production. Treatment for 7 days with intermittent HS decreased viability (P = 0.01) and diameter (P = 0.03) of preantral follicles. Relative abundances of BAX and HSPA1A mRNA transcripts were greater in follicles of the CON and HS groups that became non-viable during culture (P < 0.05); relative abundance of SOD1 mRNA transcript, however, was only greater in non-viable follicles of the HS group (P < 0.05), but not non-viable follicles of the CON group (P = 0.3). The ATP production was not different between viable follicles of the CON and HS group (P = 0.86). In conclusion, all stages of growing preantral follicles of cattle were susceptible to negative effects of heat stress. Follicles at the secondary stage of development were most sensitive, followed by early secondary and primary follicles.

β-Catenin/Tcf signaling in murine oocytes identifies nonovulatory follicles

WNTS are secreted glycoprotein molecules that signal through one of three signaling pathways. The best-characterized pathway involves stabilization of the multifunctional protein β-catenin, which in concert with members of the T-cell factor (Tcf) family activates specific gene transcription. We have examined putative Wnt/β-catenin in the murine ovary using transgenic mice harboring a reporter construct that activates β-galactosidase (lacZ) expression in response to β-catenin/Tcf binding (TopGal mice). Primordial and primary follicles did not stain for lacZ, and the proportion of β-catenin/Tcf signaling oocytes was lower than that of nonsignaling oocytes throughout estrous cycle. β-Catenin/Tcf signaling oocytes were observed in follicles from the secondary stage of development and their proportion increased with follicular maturation (secondary follicles, 20%; early antral and antral follicles, 70%). In contrast, the majority (>90%) of ovulated oocytes did not stain for lacZ. As the oocyte possesses components for WNT signal transduction, our data suggest that β-catenin/Tcf signaling is involved in the development of follicular ovulatory capability and identifies nonovulatory follicles.

Formation of specialized aerial architectures by Rhodococcus during utilization of vaporized p-cresol

When grown with vaporized alkylphenols such as p-cresol as the sole carbon and energy source, several isolated Rhodococcus strains formed growth structures like miniature mushrooms, termed here specialized aerial architectures (SAA), that reached sizes of up to 0.8 mm in height. Microscopic examination allowed us to view the distinct developmental stages during the formation of SAA from a selected strain, Rhodococcus sp. KL96. Initially, mounds consisting of long rod cells arose from a lawn of cells, and then highly branched structures were formed from the mounds. During the secondary stage of development, branching began after long rod cells grew outward and twisted longitudinally, serving as growth points, and the cells at the base of the mound became short rods that supported upward growth. Cells in the highly fluffy structures were eventually converted, via reductive division, into structures that resembled cocci, with a diameter of approximately 0.5 microm, that were arranged in chains. Most cells inside the SAA underwent a phase variation in order to form wrinkled colonies from cells that originally formed smooth colonies. Approximately 2 months was needed for complete development of the SAA, and viable cells were recovered from SAA that were incubated for more than a year. An extracellular polymeric matrix layer and lipid bodies appeared to play an important role in structural integrity and as a metabolic energy source, respectively. To our knowledge, similar formation of aerial structures for the purpose of substrate utilization has not been reported previously for Gram-positive bacteria.