Browsing by Author "Nzogela, Y."

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Changes in acidity of plant growth media during heat sterilisation
(Journal of Applied Biosciences, 2008) Msogoya, T. J.; Maerere, A. P.; Nzogela, Y.; Kusolwa, P. M.
Tissue culture media provide ideal conditions for growth of plant cells, but also bacteria and fungi. It is therefore necessary to sterilize media to remove these microbes prior to incubation of explants. Growth media are commonly sterilised by autoclaving at 121°C and pressure of 105 kPa for 15 minutes, or longer for larger volumes (Beyl, 2000). Some components of the growth media such as gibberellins (GA3) and capanthothenate are heat-labile and would become inactive when autoclaved (Nissen & Sutter, 1990). Such heat sensitive components are sterilised by filtering through bacteria-proof membrane (0.22μm pores) and added to the sterilised medium after it has cooled down to at least 60°C. Autoclaving the growth media at 121°C and pressure of 105 kPa for 15 - 20 minutes also breaks down sucrose into D-glucose and Dfructose, resulting in alteration in the osmotic potential of the growth media. Thus, it is important to consider these changes when performing osmotic-sensitive procedures such as protoplast culture. Moreover, the simple sugars resulting from sucrose degradation apparently have inhibitory effects on in vitro regeneration of some plant tissues (Dodds & Roberts, 1990).
Relationship between plant parasitic nematodes, arbuscular mycorrhizal fungi and soil characteristics on clove (syzygium aromaticum (l.) merr and perr) agroecosystem in east Usambara mountains-Tanzania
(TAJAS, 2022) Machera, S; Madege, R.R; Njau, P; Nzogela, Y.
Native communities of arbuscular mycorrhizal fungi (AMF) and plant parasitic nematodes (PPN) were examined in fields previously under climate-smart agriculture (CSA) and non-climate smart (NCSA) of the East Usambara Mountains. The field were differing in soil properties and agricultural practices. Soil samples were taken from 10 sites in each of the 30 fields. AMF spores and PPN were isolated using wet- sieving method and the Baermann tray method, respectively. The isolated fungal spores and PPN were morphologically identified, classified and quantified. A total of 10 AMF and 27 PPN genus were recorded. The CSA and NCSA fields had 51% and 56% of genus Glomus, respectively. About 73.2% and 72% of genus Rotylenchulus were recovered in CSA and NCSA, respectively. No association was found between AMF and PPN, a significant correlation between PPN and AMF abundance with agricultural practices was observed (p=0.001). No significant difference was found between AMF (p=0.8) and PPN communities (p=0.6) with agriculture practices. Correlating AMF and PPN with soil properties showed no association and no significant difference except for PPN with total nitrogen (p=0.03). Whatever the causes of no significant difference between the treatments,the results suort that CSA practices can facilitate mycorrhizal colonization.. Our results showed that both agriculture practices didnot influence AMF and PPN abundance in the soil.