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Nickel is a known hepatotoxic, haemotoxic, pulmonary toxic, nephrotoxic, reproductive toxic, carcinogenic, phytotoxic and neurotoxic agent. The adverse ecological impacts from unnecessary heavy metals include contamination of water and soil which pose serious threats to human health. This study was conducted to screen plants for the phytoremediation of nickel from sixty-one sites of the Lower Dir. Nickel-metal was analyzed in the soil, roots and shoots of plants. The total concentration of nickel in soil, roots and shoots was found to be in the range of 1.03-18.98, 12.63-540.73 and 12.00-295.86 mg kg–1 dry weight basis (DW) respectively. The highest nickel contents were present in the roots of Xanthium strumarium (540.73) and shoots of Bryophyllum daigremontianum (295.86). None of the plant species were identified as hyper accumulators for nickel but based on BCF, TF and BAC values most of the species showed feasibility for its phytoextraction and phytostabilization. Xanthium strumarium, Filago hurdwarica, Ranunculus arvensis, Medicago lupulina, Cannabis sativa, Geranium rotundifolium and Cerastium glomeratum are suggested for the phytostabilization of nickel whereas Bryophyllum daigremontianum, Rosularia adenotricha, Iris germanica, Asplenium dalhousiae and Isatis tinctoria for the phytoextraction of soil contaminated with nickel.

The release and persistence of toxic heavy metals into the natural environment is a serious concern especially in urban areas. The problem of heavy metal pollution is gaining momentum from year to year as more and more amounts of heavy metals are extracted from their ores and released into the environmental segments (water, air and soil) during processing or afterwards. Heavy metals are essentially nonbiodegradable and therefore accumulate in the environment and subsequently find their way into the food chains. Contamination of food chains by toxic heavy metals is an unwanted outcome of industrialization and unsustainable development. This contamination is a risk to the health of all organisms including humans. Entrance of toxic heavy metals (through absorption, inhalation and ingestion) into the human body beyond threshold limits causes many diseases and health abnormalities. Therefore, effective remediation of heavy metal pollution is a top priority. The different physico-chemical methods used for this purpose generally suffer from serious limitations. Phytoremediation is seen as an alternative green solution to the problem. The present study reports phytoremediation of Cd, Pb, Cu, and Zn by Trifolium alexandrinum, which is a suitable candidate plant species for this purpose. T. alexandrinum was grown in a simulated heavy metal-contaminated soil. Root bioconcentration factor values of T. alexandrinum for Zn, Pb, Cu and Cd were 4.242, 1.544, 1.071, and 0.604 respectively.

Lead poisoning has been documented as a key public health threat, mostly in developing countries. Though several public health and occupational methods have been undertaken in order to control lead exposure, cases of lead poisoning are still reported. Exposure to lead produces various deleterious effects on the hematopoietic, renal, and reproductive and central nervous system, mainly through increased oxidative stress. These alterations play a prominent role in disease manifestations. In the current paper the concentration of lead was analysed in the soil of different sites and plant parts (roots and shoots) in their natural habitat. The concentration of lead in the soil and plant parts; roots and shoots was found in the range of 1-32.3, 22-533.33 and 13.67-432 mg/Kg respectively. Bioconcentration factor (BCF), translocation factor (TF) and bioaccumulation coefficient (BAC) of all the analysed plants were calculated. The feasibility of each plant species for the phytoremediation of lead metal was evaluated on the basis of BCF, TF and BAC. The BCFs, TFs and BACs values of the plants for lead metal was found in the range of 1.86-193.33, 0.05-8.3 and 1.79-219 respectively. Most of the plant species showed feasibility for the phytoremediation of lead metal but based on its concentration in shoots and BCFs, TFs and BACs values, Erigeron canadensis L., Stellaria media (L.) Vill. Medicago minima (L.) L., Delphinium uncinatum Hook.f. & Thomson and Verbena officinalis L. were found the most efficient plants for the phytoextraction of lead while based on its concentration in roots and BCFs, TFs and BACs values, Nonea edgeworthii A. DC., Arabidopsis thaliana (L.) Heynh., Sarcococca saligna (D. Don) Muell.-Arg. in DC., Prodr., Marrubium vulgare L. and Ranunculus arvensis L. for the phytostabilization of lead metal.

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The genetic basis of salt tolerance was investigated in six bread wheat cultivars (Local white, Pavon, Pasban 90, Frontana, Tobari 66 and Chakwal 97) differing in salinity tolerance, and their F 1 crosses made in a half diallel mating design. The F 1 s and parents were germinated in pots, and were subjected to 200 mM NaCl salt stress after one month. Most of the crosses had high heterosis for yield suggesting that breeding for high yield under salt stress is possible. Narrow sense (h 2 N ) heritability estimates ranged from 0 to 51%, whereas broad sense (h 2 B ) heritability estimates ranged from 25 to 84 % for the studied traits. Additive genetic effects were significant for days to heading, days to maturity, plant height and fertile tillers plant -1 , suggesting that early selection could be useful to bring desirable changes in these characters under NaCl stress. Dominance effects were significant for yield and yield contributing traits, indicating that selection for yield under NaCl stress would be effective in later generations.

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