Within plant resistance to water flow in tomato and sweet melons

Efficient water resource management in relation to water use and crop yields is premised on the knowledge of plant resistance to water flow. However, such studies are limited and for most crops, the within plant resistance to water flow remains largely unknown. In this study, within plant resistance to water transport (hydraulic conductance) was monitored in tomato (Lycopersicum esculuntum) and sweet melon (Citrullus lanatus) using the high pressure flow meter (HPFM) and evaporative flux (EF) methods. In the evaporative flux method, measurements of transpiration flux and leaf water potential were used to calculate the total resistance to water flow using Ohm’s law analogy. Measurements of tranpiration flux (Q) relationship, plant resistance calculated from the slope of their relationship, ranged from 6.57x10-01 to 2.27x10-03 Mpa m-2s-1 for tomato and sweet melon, respectively.The magnitude of whole plant hydraulic conductance calculated by the evaporative flux method and measured on the HPFM were not significantly different. This is probably due to that fact that Kp includes the hydraulic conductance of the root system, which offers the highest resistance to water flow in a plant, and the frictional resistance of the proximal part of the crown. Day time course of water relation parameters were monitored in melon and tomato (predawn, 1100 to 1400 h). The effect of time of day was pronounced on the dynamics of water relations, particularly around mid-day when sharp differences in the magnitudes of the measured water relation parameters were obtained. Minimum (predawn) leaf water potential (øl) ranged from 0.135 to 0.207 MPa for both crops. The greatest conductance was found in the leaf and the lowest in the root in both crops. While the highest within plant resistance to the flow is contained in the root system, the stemcomponent constitutes the least resistance (greatest conductance) to within plant flow of water in tomato. Repeated measurement analysis showed the existence of significant species effects on plant water relations (leaf water potential, evaporative/transpiration flux, xylem hydraulic conductance). Superiority within plant xylem transport and evaporative losses were obtained in tomato, from the relations of EF and Kh; this crop showed a higher hydraulic sufficiency than melon. The expression of hydraulic conductance of the root and shoot systemrelative to plant attributes did not eliminate differences in the magnitudes of conductance elements in tomato and melon. Differences obtained between melon and tomato in whole plant leaf and stem area specific hydraulic conductance (KI) indicate the carbon efficiency and, hence, the cost of resource allocation to areas of root surfaceand leaves for enhanced scavenging for water and mineral nutrients. Thus, application of mineral nutrients to enhance crop productivity should take into consideration the hydraulic conductance for specific plants

Effects of synthetic hormone substitutes and genotypes on rooting and mini tuber production of vines cuttings obtained from white yam (Dioscorea rotundata, Poir)

This study was designed to evaluate the effects of some root - promoting substances on rooting and mini tuber formation using vine cuttings obtained from two genotypes (TDr 335 and TDr 93 - 49) of white yam (D. rotundata). The ashes were obtained from rice straw, bamboo, Gliricidia sepium, dry leaves of Azardiracta indica (neem), and 1% indolebutyric acid (IBA). These were powdered on the nodal wounds of vine cuttings before they were planted in planting media (carbonized rice husk). The plant ashes were mixed at 1, 3 and 5 g each in 100 ml of water. Coconut water was also diluted at 1, 5 and 10 ml in 100 ml of water while pyroligneous acid (PA) was diluted (1 ml each in 500, 1000, 2000 and 3000 ml in5000 ml of water). Both dilutions were used to treat vine cuttings before planting in cups filled with carbonized rice husk. The vine cuttings were sampled for rooting percentage, number of roots, root length and mini tuber initiation 21 days after treatment (DAT). The number and weight of tubers obtained from IBA and wood ash treated vines were not significantly different. The rice straw ash, IBA and neem leaves powder treated vines produced greater rooting percentage (above 70%) than percent rooting obtained from vines treated with other plant ashes. Rice straw ash (5% concentration) had the highest rooting percentage (80%) relative to other plants ash concentrations. Higher rooting percentage was obtained in coconut water diluted at 1 and 5% than 10 and 100% dilutions. Rooting percentages from vine cuttings treated with pyroligneous acid (PA) dilutions were not better than control (unteeated). The rooting percentages  obtained from vines treated with different concentrations of plants ashes, root - promoting substances and control in this study were not significantly different (P = 0.05), except in vine cuttings treated with 5 g rice straw ash in 100 ml of water. Higher values of rooting percentage, number of roots, root length and mini tubers were obtained from genotype TDr 93 - 49compared with values recorded from vine cuttings obtained from the genotype TDr 335

Effects of Spent Engine Oil Polluted Soil and Organic Amendment on Soil Chemical Properties, Micro-Flora on Growth and Herbage of Telfairia Occidentalis (hook f).

A trial was conducted at the Screen House of the Department of Crop Science, University of Benin, Benin City, Nigeria to evaluate the efficacy of using organic fertilizer as bioremediant for spent engine oil polluted soils. Three concentrations of spent engine oil (0, 5 and 10 % w/w, spent engine oil in soil) and three application rates of organic fertilize (0, 5 and 10 t ha-1) were utilized in a 3 x 3 factorial arrangement and laid out as a completely randomized design with three replication. Soil pH, available P and exchangeable cations were significantly reduced by spent engine oil except organic C compared to control. Heavy metals (Va and Pb) concentration increased with increasing concentration of spent engine oil. Amendment of spent engine oil polluted soil with organic fertilizer significantly remediated the degraded soil and decreases the heavy metal concentration. In addition, 10 t ha-1 organic fertilizer showed superiority over 5tha-1 organic fertilizer in amending spent engine oil degraded soil for pH, total N, available P, exchangeable Ca2+ and reduced heavy metal concentration. Soil pollution adversely affected number of leaves, dry vine weight, dry leaf weight and herbage yield. Growth and herbage yield were much higher in organic fertilizer amended spent engine oil polluted soil. the highest herbage yield (9.23 t ha-1) was obtained from unpolluted soil treated with 10 t ha-1 organic fertilizer which was statistically comparable with soil polluted with 5 % spent engine oil and amended with 10 t ha-1 organic fertilizer (7.10 t ha-1). Soils polluted with 5 % spent engine oil had higher bacteria population compared to control, while organic fertilizer had depressing effect on soil without spent oil pollution. However, unpolluted soiltreated with 10 t ha-1 organic fertilizer had the fungi (0.77 x 106cfu g-1) population which was statistically compared to 5 t ha-1 organically treated soil without spent engine oil pollution (0.76 x 106cfu g-1). Soil polluted with spent engine oil has been bioremediated with organic fertilizer and hence put into productive use.Keyword: Growth, herbage yield, micro-flora, organic fertilizer, spent engine oil, Telfairia occidentalis