The aim of this study was to test the effects of priming on the germination of deteriorated orthodox seeds of five plant species.The water content of seeds were raised to 14%, and the seeds then deteriorated to 50% viability o at 40 C and 100% relative humidity. Deteriorated seeds and fresh seeds of test species were then primed with cathodic water, un-electrophorized calcium magnesium solution and deionised water. Unprimed fresh and unprimed controlled deteriorated seeds served as controls. Germination indices were determined.In general, all priming treatments had positive effects on the germination indices of deteriorated seeds of all species, and a lesser extent on fresh seeds. However, seeds treated with cathodic water performed better than seeds treated with either CaMg solution or deionised water. While controlled deterioration reduced DNA concentrations and the DNA purity of seeds, priming, particularly with cathodic water had a protecting effect on DNA. Priming also boosted amylase activities in both fresh and deteriorated seeds.Results are consistent with cathodic water reducing oxidative stress during imbibition. Cathodic water seed priming, therefore, has the potential to play a significant role in the conservation of orthodox seeds.
The quality of seeds in gene banks gradually deteriorates during long-term storage, which is probably, at least in part, a result of the progressive development of oxidative stress. Here, we report a greenhouse study that was carried out to test whether a novel approach of seed invigoration using priming with cathodic water (cathodic portion of an electrolysed calcium magnesium solution) could improve seedling emergence and growth in two deteriorated crop seeds. Fresh seeds of Pisum sativum and Cucurbita pepo were subjected to controlled deterioration to 50% viability at 14% seed moisture content (fresh weight basis), 40 °C and 100% relative humidity. The deteriorated seeds were thereafter primed with cathodic water, calcium magnesium solution and deionized water. In addition, to study the mechanism of the impacts of invigoration, the effects of such priming on the lipid peroxidation products malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) and on the reactive oxygen species (ROS) scavenging enzymes superoxide dismutase and catalase were also determined in the fresh and deteriorated seeds. All priming treatments improved seed emergence parameters, subsequent seedling photosynthesis and growth relative to the unprimed seeds. In general, cathodic water was most effective at invigorating deteriorated seeds. Analysis of the lipid peroxidation products and antioxidant enzyme activities in invigorated seeds provided support for the hypothesis that the effectiveness of cathodic water in invigoration of debilitated orthodox seeds in general and of pea and pumpkin seeds in particular derive from its ability to act as an antioxidant.
Contamination of environmental objects and surfaces is a common phenomenon. Human beings have a marked tendency to pick up microorganisms from environmental objects, and specially the hand has been shown to play a role in the transmission of organisms. The ATM machine is likely to be contaminated with various microorganisms due to their vast contact by multiple users. This study was aimed to investigate ATM as a potential source of bacterial contamination. The study was conducted from August to October, 2013 and it involved collection of samples by using cotton swabs, culturing on different media such as nutrient agar, MacConkey as well as identifying the isolated organisms using its colonial, morphological and biochemical characteristics. The results of the study indicated that some of the Automated Teller Machines were positive for the presence of microorganisms as indicated: Staphylococcus auerus 4 (28.57%), Coagulase-negative staphylococcus 3 (21.43%), Streptococcus species 2 (14.29%), Pseudomonas species 1 (7.14%), Enterobacter species 1 (7.14%) and Escherichia coli 3 (21.43%). The antibiogram study was done using Kirby Bauer disc-diffusion method and the results showed that majority of the bacteria were highly resistant to standard antibiotics. Susceptibility of isolates ranged from 6.25% to of 25.0%, indicating that most of the antibiotics used were ineffective. Staphylococcus. aureus, Streptoccus spp and P. aeruginosa showed 68.75% resistance to the antibiotics, whilst E. coli (56.25%), Enterobacter spp (50%) and CNS showed 18.75% susceptibility each. Overall, Gentamicin was the most effective antibiotic, while Ofloxacin, Clindamycin, Cefixine, Levofloxacin and Ciprofloxacin were least effective. Hand washing after ATM usage and proper cleaning regimen should be practiced to reduce contamination on the ATMs.
Orthodox seeds deteriorate even when stored in the best of conditions; hence, it is very important to monitor germination in stored seeds. To assess orthodox seed deterioration, a germination test is usually employed. This study assessed and compared seed deterioration in five orthodox species using electrolyte leakage and Fourier transform infrared spectroscopy (FTIR). The study also compared water imbibition by the test orthodox seeds. To achieve this, the seeds from three wild (Bolusanthus speciosus; Combretum erythrophyllum; Erythrina caffra) and two agricultural (Pisum sativum and Cucurbita pepo) species were imbibed between 20 layers of single-ply paper towel. The other set was subjected to controlled deterioration at 40 °C and 100% relative humidity for 32 d, with samples taken for germination and electrolyte leakage measurement at 4 d intervals. FTIR measurements were performed at 0, 20, and 32 d of controlled deterioration. The results indicated that there were some significant interspecies differences in the imbibition times and seed water contents but these were not large. In all species, uptake of water was complete between about 15 and 25 h. The wild species showed higher sensitivity to controlled deterioration. Complete loss of germinability occurred much earlier in the wild species (20 d in B. speciosus and E. caffra, and 16 d in Co. erythrophyllum) compared with 36 d for the agricultural species P. sativum and Cu. pepo. There was a negative correlation between electrolyte leakage and seed germination in all wild and agricultural species. A strong positive correlation was observed between the time of controlled deterioration, electrolyte leakage, and FTIR transmission in all the species. While controlled deterioration may help in decisions relating to the storage of orthodox seeds, the water imbibition results from this study will help to set the priming time of the species. The study reaffirms electrolyte leakage as an indicator of seed viability in P. sativum and Cu. pepo; it also recommends the use of electrolyte leakage as an indicator of seed deterioration in B. speciosus, Co. erythrophyllum, and E. caffra. The study also recommends FTIR as a tool for monitoring the germination of stored seeds of all the test species.
Field experiments were carried out during the summer/autumn (first trial) and winter/spring (second trial) seasons of 2019 and 2021 in the Dlangubo, Ngwelezane, and Mtubatuba areas of KwaZulu-Natal Province of South Africa to study the drought amelioration effects and impact of two locally available organic wastes (filter cake—a residue derived from sugar cane filtration (FC) and macadamia husk compost (MHC)) on the productivity and physiological responses of four orange-fleshed sweet potato cultivars (Beauregard cv., Impilo, W-119 and 199062.1). The effects of FC and MHC were compared with that of inorganic fertilizer (IF) [2:3:2 (30)], FC + IF, MHC + IF, and the control. The soil amendments were applied in the first trials only. Climatic data such as humidity, temperature, and rainfall were taken via remote sensing. The results of the first trial indicated that filter cake and IF significantly performed better than MHC. The strength of filter cake may be attributable to its rich array of mineral nutrients such as calcium, magnesium, potassium, sodium, zinc, copper, manganese, iron, and phosphorus. The limited performance of MHC may be attributable to its ability to hold water. Furthermore, a positive correction occurred between the yield of the test orange-fleshed sweet potato (OFSP) cultivars, rainfall, and vegetation indices (normalized difference vegetation index, enhanced vegetation index, and normalized difference water index) investigated in the study. In season two, IF treatment did not have any significant effect on the growth and productivity of any of the tested sweet potato cultivars, but, FC, FC + IF, and MHC treatments largely maintained their performances. In conclusion, the use of FC is highly recommended in the production of the test OFSP cultivars. Furthermore, the study indicates that both FC and MHC may not only supply the needed plant nutrients but has the capacity to reduce the impact of drought on the growth of the test cultivars. These findings are of great value to farmers, especially the resource-poor ones.
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