Search Results

You are looking at 1 - 8 of 8 items for :

  • Author or Editor: M. Ashraf x
  • Biology and Life Sciences x
  • Refine by Access: All Content x
Clear All Modify Search

Salinity reduces plant growth and yield by affecting morphological and physiological processes. To alleviate the harmful effects of salt stress various approaches involving plant hormones are used. In this study several parameters involving the measurement of cell membrane injury were used to observe whether stress tolerance could be enhanced in Chinese cabbage (B. oleracea capitata L. Chinensis group) by soaking the seeds for 10 h in distilled water (control), or in 100, 150 or 200 mg l−1 gibberellic acid (GA3). The NaCl concentrations were 0 (control), 50, 100 and 150 mM. Seed treated with GA3 showed increased water uptake and decreased electrolyte leakage as compared to that of distilled water-primed seeds even 24 h after soaking under control conditions. Seed priming with GA3 increased the final germination and the germination rate (1/t50, where t50 is the time to 50% germination) under salt stress conditions. Seed priming also alleviated the harmful effect of salt stress on cabbage in terms of fresh and dry weights. Leaf area was higher in plants raised from seeds primed with the higher GA3 concentrations as compared with those raised from seeds treated with distilled water under control conditions (without NaCl) or at 50 mM NaCl stress. The chlorophyll content increased with the NaCl concentration, especially in plants grown from seeds primed with GA3. Plants grown from GA3-primed seeds also suffered lower cellular injury both under control conditions and under NaCl stress.

Restricted access

A pot culture experiment was conducted to study the influence of NH 4 Cl (AnalaR grade or commercial fertilizer) on soil pH and on the growth, yield and nutrient uptake of cotton (cv. NIAB-Karishma) grown in alkaline soil. The experiment was carried out in a net-house under natural conditions. The soil used was clayey loam with pH 8.61, and ammonium chloride either from commercial fertilizer or of AnalaR grade (both containing up to 25% N) was applied in three split doses, after germination (10 days), at the vegetative stage (40 days) and at the flowering stage (80 days) @ 6, 12 and 18 kg ha −1 . The application of NH 4 Cl decreased the soil pH and increased the plant height and cotton yield plant −1 . Plants treated with NH 4 Cl AnalaR grade produced higher yields as compared to NH 4 Cl commercial fertilizer. The uptake of micronutrients such as Fe, Cu, Zn and B was enhanced by NH 4 Cl application in both the stem and leaves of cotton. However, AnalaR grade NH 4 Cl proved more effective than NH 4 Cl commercial fertilizer in all cases.

Restricted access

Five distinct habitats along salinity gradient were explored for plant ecological attributes including soil plant interaction, vegetation composition and species distribution in the Cholistan desert. Higher saline sites supported Sporobolus ioclados with Aeluropus lagopoides, Cymbopogonjwarancusa, Ochthochloa compressa, Haloxylon recurvum and Suaeda fruticosa , whereas moderately saline habitats supported predominantly Fagonia indica, C. jwarancusa and O. compressa . The community structure and composition of each habitat type were very specific, the most dominant component being S. ioclados . Each species has very specific relation to different environmental variables, and this reflects the habitat status, ecological adaptations and stress tolerance degree of the individual species. On the whole, it can be concluded that salinity alone was not responsible for the distribution of species at salt affected habitats.

Restricted access

Application of salt stress (100 mM) through root growing medium caused a considerable decrease in plant fresh and dry biomass, maximum quantum yield (F v /F m ), chlorophyll contents, leaf water potential, and leaf Ca, K, P and N concentrations of two maize cultivars (Apex 836 and DK 5783). However, salt-induced increase was observed in leaf osmolality (LO), proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), Na+ concentration and activities of enzymatic antioxidants, such as catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Of five humic acid (HA) levels used under non-stress and stress conditions in an initial experiment, 100 mg L−1 was chosen for subsequent studies. Exogenous application of humic acid (HA) at the rate of 100 mM as a foliar or pre-sowing seed treatment significantly increased the plant biomass, F v /F m , chlorophyll pigments and proline contents, while it considerably reduced the leaf water potential, H2O2 and MDA contents as well as the activities of all the afore-mentioned enzymatic antioxidants. Of both modes of exogenous treatment, foliar spray was better in improving plant biomass, chlorophyll contents, LO, leaf Na+ as well as the accumulation of all nutrients measured, however, in contrast, seed pre-treatment was more effective in altering leaf proline, H2O2 and MDA contents. Of both maize cultivars, cv. DK 5783 excelled in plant biomass, chlorophyll contents and leaf N, Ca and K concentrations as well as in the activities of all three antioxidant enzymes, whereas cv. Apex 836 was superior in leaf Na+ and P concentrations, H2O2 and MDA contents. Cv. DK 5783 was comparatively better in salt tolerance as compared to cv. Apex 836. Overall, exogenous application of HA was effective in improving salinity tolerance of maize plants which can be attributed to HA-induced increase in plant biomass, chlorophyll contents, mineral nutrients and activities of key antioxidant enzymes.

Restricted access

Abstract

The present manuscript demonstrates the work undertaken to optimise and validate a slow-release amylase-assisted extraction of polyphenols from peach fruit peel. A careful investigation and optimisation revealed that peach peel when hydrolysed with 1.50% (w/w) of SRA containing enzyme formulation at 40 °C and 6.1 pH, for 35 min significantly (P < 0.05) increased the extraction yield, levels of polyphenol contents (242.89 ± 1.56 mg gallic acid equivalents – GAE), and coumaric, chlorogenic, ferulic acids or their conjugate esters in extracts. Moreover, the extracts produced through SRA-assisted extraction exhibited ample level of free radical scavenging capacity (DPPH IC50 2.67 ± 0.03 μg mL−1), Trolox equivalent (TE) antioxidant capacity (450.52 ± 24.58 µmol of TE g−1), inhibition of peroxides in linoleic acid (85.68 ± 0.21%), and ferric reducing power of 3.11 ± 0.20 ppm gallic acid equivalents. The results suggested that the incorporation of SRA containing enzyme formulation may enhance the recovery of peach peel polyphenols while hydrolysing the glycosidic linkages without deteriorating their antioxidant character.

Restricted access

A study was conducted on the sheep farm of the Livestock Experimental Station, located in the southwestern Punjab, Pakistan, to determine the copper nutrition status of different classes of grazing sheep during two different seasons. A complete free-choice supplement (feed) was available to all animals throughout the year. The purpose of this research was to investigate, as a function of the seasons, the transfer of Cu from soil, and dietary factors to sheep grazing in this semiarid region, in order to evaluate if the Cu requirement of grazing livestock was met or if a deficiency occurred. The final goal was to maximize the production of the animals by adopting, if necessary, adequate, balanced Cu supplementation. Soil, forage, feed and water samples, and animal samples (plasma, milk, faeces and urine from lactating ewes, plasma, faeces and urine from non-lactating ewes and plasma and faeces from male animals) were taken eight times during the year (four times in each season). Soil copper was affected by the seasonal changes and sampling intervals and was significantly higher than plant needs during both seasons, while the forage copper level did not show significant seasonal fluctuations, but was only affected by the sampling intervals. The soil and forage Cu was sufficient for the requirements of the plants and the animals grazing there on during both seasons. The copper contents of the feed and water showed no seasonal or sampling interval fluctuations. The plasma Cu was affected by seasonal variations in non-lactating ewes and in rams and by sampling intervals in the lactating ewes. Faecal and urine Cu was not affected by seasonal or sampling intervals except in non-lactating ewes, where the sampling interval had a pronounced effect on faecal Cu, while milk Cu in lactating ewes was affected by seasonal changes only. In all classes of sheep plasma Cu was higher during the winter than during the summer and remained in the normal range for ruminants during both seasons. It is concluded that a mixture with high bioavailability, containing Cu, should be continuously provided to grazing sheep in this semi-arid region in order to maintain the normal level of Cu and maximize the production potential of ruminants.

Restricted access

Alkaline and acidic pH of soil limit crop yield. Products of phenylpropanoid pathway play a key part in plant abiotic stress tolerance. It was aimed to assess efficacy of tyrosinepriming for activation of enzyme involved in phenolic accumulation induction of pH tolerance in maize seedlings. Seeds of two maize cultivars, namely Sadaf (pH tolerant) and S-2002 (pH sensitive), were grown under three pH levels (3, 7 and 11). Eight and twelve days old seedlings were harvested and parted into roots and shoots for the assessment of growth, enzymatic and non-enzymatic antioxidants. PAL activity was directly correlated with total soluble phenolics, flavonoids, growth and seedling vigour. Lower accumulation of phenolics and PAL activity in the pH sensitive (S-2002) cultivar indicated greater oxidative damage caused by pH extremes. Priming improved antioxidative potential by enhancing PAL activity and phenolics accumulation and hence increased growth in maize seedlings.

Restricted access

Recently, super rice has gained much importance due to its high yield potential while exogenous application of plant growth regulators (PGRs) is an important aspect in plant development and defense responses under stress conditions. In this study we conducted two pot experiments. Firstly, four super rice cultivars, viz. Peizataifeng, Huayou 213, Yuxiangyouzhan and Huahang 31 were subjected to a series of five chilling temperatures, i.e. 11 °C, 12 °C, 13 °C, 14 °C and 15 °C (day/night) for about 25–27 days. Secondly, seeds of Peizataifeng (super rice) and Yuejingsimiao 2 (non-super rice) were then treated with different combinations of salicylic acid (SA), brassinolide (BR), calcium chloride (CaCl2) and fulvic acid (FA) and then exposed to chilling stress at 13 °C for four days. Resultantly, Peizataifen (super rice) was found with the lowest seedling survival rate at all chilling temperatures among all four super rice cultivars, however, it was still found more resistant when compared with Yuejingsimiao 2 (non-super rice) in the second experiment. Furthermore synergistic effect of all PGRs alleviated low temperature stress in both rice cultivars by improving seedling survival rates, leaf area, seedling dry weight, seedling height, root morphology and by modulating antioxidant enzymes, improving proline content and lowering lipid peroxidation.

Restricted access