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Cadmium (Cd) has no known role in plant biology and is toxic to plants and animals. The Cd mainly accumulated in agricultural soils through anthropogenic activities, such as sewage water irrigation and phosphorus fertilization. Biochar (BC) has been proposed as an amendment to reduce metal toxicity in plants. The objective of this study was to evaluate the role of BC (cotton stick at a rate of 0, 3, and 5 %) on Cd uptake and the photosynthetic, physiological, and biochemical responses of spinach (Spinacia oleracea) grown in Cd-spiked soil (0, 25, 50, 75, and 100 mg Cd kg soil). The results showed that Cd toxicity decreased growth, photosynthetic pigments, gas exchange characteristics, and amino acid and protein contents in 52-day-old spinach seedlings. The Cd treatments increased the concentrations of Cd, sugar, ascorbic acid, and malondialdehyde (MDA) in plants. The application of BC ameliorated the harmful effects of Cd in spinach plants. Under Cd stress, BC application increased the growth, photosynthesis, and protein contents and decreased Cd concentrations and MDA contents in plants. The maximum BC-mediated increase in dry biomass was about 25 % with 5 % BC application in control plants. It is concluded that BC could ameliorate Cd toxic effects in spinach through changing the physiological and biochemical attributes under Cd stress.

Heavy metals toxicity in the human being is creating an alarming condition in the world. Not only are these metals largely effecting the growth of many plants but also the consumer's health. In sector of agriculture for many years Pakistan is facing the reduction in availability of edible oil. The demand is fulfilled by importation by spending huge cost. Brassica campestris L. is very important oil seed crop of Pakistan that is providing 31% of total oil seed production in Pakistan. But due to toxicity of metals like Cd and Pb its growth and yield is decreasing. Keeping in view the importance of Brassica campestris L. in Pakistan an experiment was conducted using Pollutary manure biochar as a reclaiming agent for heavy metals and an amendment as drought stress reducer to check the improvement in yield of Brassica campestris L. It is found that biochar application not only gave positive correlation in immobilization of Pb and Cd but also improves the plants growth and yield. Enhancements in the Photosynthetic and Accessory pigments are observed regarding good vegetative growth. Thus biochar can be utilized in reducing the metals uptake as well as growth promoter.

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Irrigation of arable land with contaminated sewage waters leads to the accumulation of trace metals in soils with subsequent phyto‐/zootoxic consequences. In this study, biochar derived from cotton sticks was used to amend an agricultural silt‐loam soil that had been previously irrigated with trace metal contaminated sewage waters. Metal accumulation and toxicity to spinach (Spinacia oleracea) and fenugreek (Trigonella corniculata) was investigated by measuring concentrations of Cd and Ni in plant tissues and various photosynthetic and biochemical activities of plants. Positive impacts of biochar on both spinach and fenugreek were observed in terms of biomass production that increased from 29% to 36% in case of spinach, while for fenugreek this increase was 32% to 36%. In the control treatment there was an increase in malondialdihyde, soluble sugar, and ascorbic acid contents, indicating heavy metal stress. Biochar applications increased soluble proteins and amino acids in plants and reduced the uptake of Cd from 5.42 mg kg−1 at control to 3.45 mg kg−1 at 5% biochar amended soil and Ni (13.8 mg kg−1 to 7.3 mg kg−1 at 5% biochar) by the spinach plants. In fenugreek, the Cd was reduced from 7.72 mg kg−1 to 3.88 mg kg−1 and reduction in Ni was from 15.45 mg kg−1 to 9.46 mg kg−1 at 5% biochar treated soil, reducing the possibility of transfer up the food chain. This study demonstrates that the use of biochar made from cotton‐sticks, as an amendment to arable soils that have received contaminated irrigation water, could improve plant growth and decrease Cd and Ni uptake to crops, alleviating some of the negative impacts of using sewage waters on arable land.

Physical seed traits such as seed weight, volume and density are determinants of seed vigour in cotton, while seed surface area is of prime importance in lint production. Two Pak-upland cotton crosses, plus their parental, F 2 and back cross generations were evaluated over two years to determine the inheritance pattern of their seed physical traits under heat stress and non-stress field regimes. The heat stress regime suppressed the average expression of seed traits in all generations. The results showed there to be low genetic variability with respect to physical seed traits, particularly seed volume, seed density and seed surface area, among several generations of the two cotton crosses. The inheritance of seed physical traits was complex in both crosses due to the presence of substantial non-allelic interactions (digenic epistatic effects) and the influence of generation × temperature regime interaction. The two crosses expressed different patterns of inheritance for seed physical traits. Those governing seed volume and seed surface area were highly sensitive to the temperature regime in both crosses and were controlled by additive genetic effects under heat stress conditions, and by dominant genetic effects under non-stress regime. The non-stress regime favoured the expression of dominant genetic effects. From a breeding point of view, the heat stress regime could be a more favourable environment for enhancing selection efficiency.Additional key words: genetic effects, Gossypium, heat stress, seed vigour. ResumenLa herencia de caracteres físicos de la semilla de algodón de tierras altas bajo diferentes regímenes de temperaturaCaracteres físicos tales como peso, volumen y densidad son determinantes en el vigor de la semilla y, en el caso del algodón, el área superficial de la misma es fundamental en la producción de las hilas. Con el fin de comprender el patrón de la herencia de los caracteres físicos de semillas de algodón sometidas a estrés por altas temperaturas y sin estrés, se evaluaron durante dos años dos cruces de algodón de tierras altas de Pakistán y sus parentales, así como generaciones F 2 y de retrocruzamiento de ambos parentales. El régimen de estrés por altas temperaturas suprimió la expresión media de los caracteres de las semillas en todas las generaciones. Los resultados revelaron una menor variabilidad genética en varias generaciones de los dos cruces para caracteres físicos de la semilla analizados, particularmente aquéllos asociados con el volumen, la densidad y el área superficial de la semilla. La herencia de los caracteres físicos de la semilla fue compleja en ambos cruces debido a la presencia de interacciones no alélicas (efectos epistáticos digénicos) y a la interacción generación × régimen de temperatura. Los dos cruces expresaron patrones diferentes de herencia para caracteres físicos de semilla. El patrón de herencia del volumen y área superficial de la semilla en ambos cruces mostró una alta sensibilidad a la temperatura, y estuvo controlado por componentes aditivos bajo...

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