Search Results

You are looking at 1 - 6 of 6 items for :

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

The effects of aluminium on seed germination, shoot, root and dry weight of two wheat cultivars were studied. The seed germination of Triticum aestivum cv. 'Faisalabad 85' and Triticum aestivum cv. 'Blue Silver' was significantly (p < 0.05) affected by different concentration of aluminium as compared to the control. The increase in concentration of aluminium at 10 ppm suppressed the root and shoot length in T. aestivum cv. 'Faisalabad 85', whereas the reduction in shoot length was observed for T. aestivum cv. 'Blue Silver' at 15 ppm. A significant (p < 0.05) reduction in dry weight of 'Blue Silver' was observed at 25 ppm aluminium.

Restricted access

Detection of genotypic variation in response to water stress at seedling stage could help in escalating selection intensity in breeding drought tolerant varities. Nine genotypes were tested for seedling survivability under drought stress. Four genotypes, i.e. ‘Sarsabz’, ‘Sitta’, ‘Fareed’ and ‘FD-83’, showed complete survival on resumption of irrigation after drought stress. These genotypes were late dying as they withered slowly under drought. Percent wilting and percent survival on resumption of irrigation were negatively correlated. Six genotypes were selected on the basis of seedling survivability (late and early dying) and evaluated for seedling growth response under drought. Root length and dry weight increased significantly under stress in ‘Sitta’, ‘FD-83’ and ‘Fareed’. Drought stress also increased the root-to-shoot length ratio in ‘FD-83’ and ‘Fareed’. However, seedling fresh and dry weight significantly reduced in ‘Nesser’ and ‘Inqalab-91’ under stress. In ‘FD-83’, seedling fresh and dry weight increased over control under stress. Results indicated that seedling survivability, root-to-shoot length ratio, root length and dry weight were most important traits for screening drought tolerance at seedling stage. On the basis of these indices, ‘Sitta’, ‘Fareed’ and ‘FD-83’ were classified as drought tolerant, ‘Sarsabz’ and ‘Nesser’ as moderately tolerant and ‘Inqalab-91’ as sensitive genotypes. Collectively, results suggested that selection by combining seedling survivability, growth response, RWC and leaf water potential can be efficiently used for rapid evaluation of drought tolerance in wheat breeding.

Restricted access

The reduction in seed germination and seedling growth varies with plant species, salinity level and ionic composition of the salts present in soil solutions. Seed germination of Leucaena leucocephala and Prosopis juliflora were affected in soil extract of all halophytic communities. Significant (p < 0.05) reduction in seed germination of Thespesia populnea was found in soil extract of Cressa-Suaeda-Atriplex and Suaeda-Heliotropium-Tamarix community. The root growth of P. juliflora was significantly reduced in soil extract of Haloxylon-Suaeda-Atriplex community. Significant inhibition in shoot growth of L. leucocephala and P. juliflora were found in soil extract of Haloxylon-Suaeda-Atriplex community. L. leucocephala and T. populnea showed low tolerance in soil extract of Cressa-Suaeda-Atriplex community. P. juliflora demonstrated low tolerance in soil extract of Haloxylon-Suaeda-Atriplex community. The soil collected from different community showed variation for soil conductivity and cations. The highest sodium (11,500 µg/g) was observed in Suaeda-Heliotropium-Tamarix community. Salsola-Fagonia- Zygophyllum community exhibited the lowest concentration of sodium and potassium, 500 and 75 µg/g, respectively. It was found that sodium was directly proportional to the conductivity of the soil extract.

Restricted access

Mechanisms involved in salt tolerance urge exploration and investigation of genotypic variation to assist future breeding programs. Comparative examination of ten wheat cultivars for salt tolerance and their response towards proline-seed-priming was performed. Exposure of wheat seedlings to salinity resulted in prominent reduction in root and shoot growth attributes of all cultivars. Furthermore, decrease in the chlorophyll contents was evident although this varied among cultivars. Wheat seedlings grown from proline pre-treated seeds exhibited improved photosynthetic pigments, besides this response was also cultivar and concentration dependent. Generally, salt stressed plants exhibited higher antioxidant enzyme activities. Proline priming significantly influenced antioxidant activities, however, its magnitude varied. The peroxidase activity varied among wheat cultivars that were evident from the analysis of POD activity on Native-PAGE gel. Salinity caused the accumulation of Na+ in the roots and the magnitude of Na+ translocation to the shoot was cultivar dependent. Similarly, K+ uptake and its distribution among root and shoot varied. Priming treatments affected ion distribution of Na+ and K+ but inter-cultivar variations were evident. Conclusively, all the cultivars investigated exhibited differential response to salinity and proline seed pre-treatments. However, the proline-priming mediated improvements in growth and antioxidant enzyme activities contributed to stress tolerance which partly relied on the ability of the plant to uptake sodium and its partitioning in the roots. Of the cultivars tested, Faisalabad-08 and Bhakhar-2002 were ranked as relatively salt tolerant and the cvs. AARI-10, MH-97 and Auqab-2000 as relatively salt sensitive.

Restricted access

Rice germplasm comprising wild species, low land and upland genotypes and 7 progenies of their inter-specific hybrids were tested under water levels of field capacity (100% moisture) and 75, 50 and 25% of field capacity. The objectives were to identify i) most water stress tolerant genotype, ii) characters associated with that genotype and iii) its ability to contribute water deficiency tolerance to lowland rice varieties. Experiment was conducted in potted soil with Randomized Complete Block two-factor factorial design and three replications. Different growth parameters were studied at tillering stage. Within an entry, reduction due to water level was significant in all the parameters. The interaction between various water levels and rice entries was also highly significant. We observed six parameters (shoot length, root length, shoot and root dry weight, number of tillers and leaf area) that were comparatively less affected in some of the progenies such as WAB-56-50 (shoot dry weight and root length), WAB-56-104 (root dry weight and tillers), WAB-272-H3 (leaf area) and WAB-272-H2 (shoot length) when tested under water level which is only 25% of the field capacity. This indicated that using these progenies as donor; water deficiency tolerance in lowland rice cultivars can be improved.

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