Muhammad Zafar Iqbal

The Toxicity Effects of Heavy Metals on Germination and Seedling Growth of Cassia siamea Lamk

ABSTRACT The effect of lead and cadmium on seed germination, seedling length, root length and seedling dry weight of Cassia siamea was evaluated under laboratory conditions with and without phytotoxic metal ions (Pb and Cd) at 25, 50, 75, and 100 ppm. Lead treatment at 25-100 ppm produced significant (p < 0.05) effects on seedling length and dry weight as compared with control. Lead treatment at 50-100 ppm produced significant (p < 0.05) effects on seed germination and root length of C. siamea. Similarly, cadmium treatment at 25-100 ppm produced significant (p < 0.05) effects on seed germination, seedling length and seedling dry weight of C. siamea as compared with control. A significant (p < 0.05) reduction in root growth was observed at 50 ppm cadmium concentration. Seedlings of C. siamea showed gradual decrease in tolerance with an increase in concentration of lead and cadmium. Tolerance in C. siamea seedlings at 100 ppm of lead and cadmium treatment was lowest as compared with control. Cadmium treatment showed more pronounced effects on seedlings of C. siamea as compared with lead.

Tolerance of Peltophorum pterocarpum D. C. Baker Ex K. Heyne Seedlings to Lead and Cadmium Treatment

ABSTRACT Trace metals present in the environment are hazardous to ecological systems and also to human health and plant growth. In this study, lead and cadmium treatments affected the growth indices of Peltophorum pterocarpum. Lead treatment at 25-100 ppm produced significant (p < 0.05) effects on seedling dry weight of P. pterocarpum as compared with control. Root growth was significantly (p < 0.05) reduced at 50-100 ppm treatment of lead. Increased concentration of lead treatment at 75-100 ppm produced significant (p < 0.05) effects on seed germination and seedling length of P. pterocarpum as compared with control. Cadmium treatment at 50-100 ppm also produced significant (p < 0.05) effects on root growth of P. pterocarpum as compared with control whereas 75-100 ppm produced significant (p < 0.05) effects on seed germination and seedling length. Root growth was affected more than shoot growth at all treatments of cadmium as compared with control. Seedlings of P. pterocarpum were tested for tolerance to lead and cadmium at 25, 50, 75, and 100 ppm concentrations. Seedling of P. pterocarpum showed decreased tolerance with increased concentration of lead. Cadmium treatment at 100 ppm exhibited the lowest tolerance in tree seedlings of P. pterocarpum as compared with lead.

Seed Germination and Seedling Growth of Trees in Soil Extracts from Korangi and Landhi Industrial Areas of Karachi, Pakistan

Abstract The effects of soil extracts from Khan Towel, Tanveer Garment, One Tech Rubber, and One Tech Ply Board factories in the vicinity of Korangi and Landhi industrial areas on seed germination and growth of cultivated plants like Albizia lebbeck, Leucaena leucocephala, Thespesia populnea, and Peltophorum pterocarpum and naturally growing plants such as Prosopis juliflora (Karachi University and Korangi and Landhi industrial areas) were studied under laboratory conditions. Soil extract of Khan Towel factory soil caused percentage reductions in seedling dry weight (66.7%) of L. leucocephala and seed germination (5.3%) of P. pterocarpum relative to the control soil extract (Karachi University soil). Soil extract from Tanveer Garment factory soil induced percentage reductions in many growth variables like seed germination (60.9%), root (84.2%), shoot (54.1%) and seedling length (which include shoot length also) (72.2%) of L. leucocephala over the control. Percentage was also reduced in seed germination (50%), root (27.9%), and seedling length (6.6%) of T. populnea from Tanveer Garment factory soil as compared with the control. Soil extract of One Tech Rubber factory caused percent reductions in root (58.5%), shoot (46.9%), and seedling length (48.6%) of A. lebbeck relative to the control. Soil extract of One Tech Ply Board factory soil induced percentage reductions in root (11.3%), shoot (8.1%), and seedling length (9.8%) of Prosopis juliflora (seeds were collected from Karachi University) over the control. Highest amount of total soluble salts (137.3%) was found in the soil of Khan Towel factory as compared with the control. Tanveer Garment factory had lower amount of organic matter (55%) in soil and higher amount of zinc (733.3%) in soil extract relative to the control. In the case of One Tech Rubber factory the concentrations of calcium carbonate (105.1%) in soil and ferric (9.3%) in soil extract were higher over the control. Soil of One Tech Ply Board factory had higher amount of organic matter (65%) and available sulfate (7500%) and reduced concentration of calcium carbonate (1.7%) over the control. The amount of ferric (28.5%) was high in soil extract from One Tech Ply Board factory relative to the control.

Time-efficient control law for position tracking of robotic arm

This paper presents a time-efficient control law for the position tracking of single link robotic arm. The proposed control law can be modified or extended to use for other applications. Global asymptotic stability of the closed-loop is assured based on the Lyapunov function. Computer simulation and laboratory scale experimental results show that set-point tracking is fast compared to that of the standard PD controller. The control and output signals are oscillation free.

Plant and soil relationship in different halophytic communities.

In inland halophytic communities, six plant communities were recognized on the saline area in which Suaeda fruticosa was the most dominant species followed by Haloxylon recurvum and Cressa cretica, respectively. S. fruticosa and H. recurvum showed good relationship with each other. Sodium was the predominant cation in all the sites. The halophytic communities reveal interesting correlations with different edaphic factors. Although, sodium was predominant cation in all the sites, yet each community had its own set of edaphic control. The soil of the study area was sandy and alkaline in nature. The soil had poor organic carbon and moderate percentage of water holding capacity. Electrical conductivity ranged from 4.6 – 12.5 mS.cm−1.