Effect of osmotic potential of activator solution and temperature on viability and vigour of wheat seed

Experiment was conducted to investigate if seed priming with polyethylene glycol (PEG) activator solutions affects the viability and vigour of deteriorating wheat (Triticum aestivum L. cv. Caxton) seed lot. Seeds were subjected to PEG priming solutions with varying osmotic potentials (-1, -2, -3 MPa) at temperatures of 15 or 20°C for 6, 12, 18 or 24 h and compared to the non-primed control. Highest germination percentage at first and final count, length of plumule and dry weight of seedling were all associated with Treatment 1 MPa/20°C/6 h (92%, 94%, 9.2 cm, 0.0133 mg, respectively) compared to the control (82.5%, 86%, 7.8 cm, 0.0112 mg, respectively). The best values of coefficient of velocity of germination (CVG), mean germination time (MGT) and germination rate index (GRI) were associated with Treatment 2 MPa/15°C/24 h. There were significant interactions between the factors under study and whilst most positive effects decreased with incubation time the opposite was true at 15°C Treatment 2 MPa where an initial decrease in germination after 6 h was restored with longer incubation times. Significant correlations were found between most of the characteristics under study although these did not always account for a high percentage of variation but CVG and MGT were very highly correlated. It was concluded that, 6 h in Treatment 1 MPa PEG at a temperature of 20°C resulted in significantly improved germination percentage whilst 24 h Treatment 2 MPa at 15°C was optimal for the highest CVG and MGT. The highest speed of germination was not associated with the highest germination percentage

The improved phytoextraction of lead (Pb) and the growth of maize (Zeamays L.): the role of plant growth regulators (GA3 and IAA) and EDTA alone and in combinations.

This investigation was made to examine the role of gibberellic acid (GA(3)), indole-3-acetic acid (IAA) and EDTA in improving phytoextraction of the Pb and plant growth on Pb added soil. GA(3), IAA and EDTA were applied separately and in combinations. GA(3) and IAA were applied as foliar spray and seed soaking. EDTA was applied in single and split doses. Analysis of the Pb in different parts of plant was carried out using atomic absorption/flame spectrophotometer. EDTA significantly reduced the plant growth and dry biomass, whereas GA(3) and IAA foliar spray increased it significantly when compared with control (only Pb added soil). In combined treatments of EDTA+GA(3) and EDTA+IAA, the growth and biomass was restored, which shows that GA(3) and IAA did compensate the negative effect of EDTA on plant growth. The separate treatments of EDTA, GA(3) and IAA increased the Pb uptake and translocation significantly moreover in combine treatments, synergistic effect was found and remarkable increase in Pb uptake and translocation into shoot was observed. EDTA increased the Pb uptake but declined the biomass; subsequently the total Pb accumulation was decreased in plant. The maximum total Pb was found in combined treatment of EDTA+GA(3). These findings suggest more investigation to find a combination of GA(3) with a very low concentration of EDTA, as in high concentration it causes soil and ground water pollution

Effect of nitrogen on safflower physiology and productivity

Safflower (Carthamus tinctorius L.) is an oil-crop suitable for semi-arid agriculture, but its physiological response to agronomic inputs has yet to be fully evaluated. The effect of fertiliser on the physiology and production of safflower grown in pots filled with standard grade perlite inside a semi-controlled glass house was studied. Plants were initially irrigated with 20-100 ml standard hydroponic solution and then one month after germination plants were irrigated using 50-200 ml complete Hoagland’s solution, supplemented with one of eight levels of nitrogen (0, 25, 50, 75, 100, 125, 150, 175 kg N ha-1) in the form of ammonium nitrate. Elevating nitrogen to 100 kg N ha-1 significantly increased the assimilation rate by about 42 %, transpiration rate by 32%, stomatal conductance by 52% and LAI by 42% compared with the control. The above ground dry weight, seed yield and Water Use Efficiency (WUE) increased incrementally with increases in nitrogen rate. Above ground dry weight increased by an average of 42%, seed yield by 76% and WUE by 41% at harvest compared with the control. This study clearly demonstrates how nitrogen fertilisation can affect physiology of safflower leading to improvement in seed yield

Identification and expression analysis of CBF/DREB1 and COR15 genes in mutants of Brassica oleracea var. botrytis with enhanced proline production and frost resistance.

Frost resistant mutants of Brassica oleracea var. botrytis were investigated for the presence of CBF/DREB1 and COR15a gene products and induced frost resistance. Total RNA of clones was isolated after 3 h, 6 h, 24 h and 14 d acclimation at 4 °C and proteins and free proline were isolated after 14 d acclimation. cDNA was produced using RT-PCR and the first CBF gene in B. oleracea detected and did quantify. Through SDS-PAGE and Western blotting, the COR15a protein was detected for the first time in B. oleracea. The results confirmed the first report of the presence of BoCBF/DREB1 in B. oleracea and this only appeared under cold acclimation. The sequence analysis of predicted amino acids revealed a very high homology (90%) with CBF sequences of other Brassica species (BnCBF5/DREB1, BrDREB1 and BjDREB1B) and homology reduced to 67% when compared to plants other than Brassicas. BoCBF/DREB1 transcript levels increased up to 24 h acclimation and then declined. Some mutants showed BoCBF/DREB1 expression at 3 h while others only after 6 h and 24 h acclimation. The genotypes showed positive significant correlation between BoCBF/DREB1 expression and frost resistance (R(2) = 0.9343). The proline level under acclimation increased about 8 fold and demonstrated positive and significant correlation with BoCBF/DREB1 expression. Proline also showed positive and significant correlation with frost resistance under cold acclimation but very not under non-acclimation. All clones were positive for COR15a protein after 14 d cold acclimation and expression correlated with frost resistance. Under non-acclimation COR15a was constitutively expressed in 3 mutants

Effect of soil applied zinc sulphate on wheat (Triticum aestivum L.) grown on a calcareous soil in Pakistan

A field experiment was conducted to investigate the effect of soil application of zinc fertilizer on yield and yield components of wheat (Triticum aestivum L. cv. Inqlab 91) grown on calcareous soil in Pakistan. The levels of zinc sulphate were 0 (control), 5, 10, 15, 20, 25 and 30 kg ha-2 and the zinc sulphate was combine-drilled at the time of sowing. Zinc sulphate increased the Leaf Area Index, the total number of fertile tillers m -2, number of spikelets spike-2, spike length, grain spike-2, thousand grain weight, grain yield, straw yield and biological yield and decreased harvest index. Most of the response trends were curvilinear although the decrease in harvest index was linear. All applications of zinc sulphate gave economic increases in margins over costs but the application of 5 kg ha-2 gave the highest marginal rate of return. It is recommended that under such calcareous soil conditions growers can expect good returns from the application of 5 kg zinc sulphate ha-2 at the time of sowing but if the grain price were to increase or the price of zinc sulphate were reduced economic responses could be expected from higher levels of zinc sulphate. © 2008 Akadémiai Kiadó