Hibiscus cannabinus L. or Kenaf is one of the most potential annual crop planted throughout the world. Being fast growing and multipurpose, it has been utilized as a substitute of jute and, more recently, as raw product for the production of pulp and paper. With strong and long fiber yield, mass production of Kenaf throughout Malaysia is critical. The utilization of less fertile soils such as BRIS soils is important to increase the Kenaf production throughout Malaysia. Thus, the objective of this study was to determine the effects of different level fertilizer application on growth and physiology of Kenaf planted on BRIS soils. V36 variety was used and planted in three different plots by treatments with fertilizers namely high (1960 kg/ plot), medium (1260 kg/ plot) and low (700 kg/ plot) respectively. Each plot comprises 106,000 trees where trees were planted on 20 lines. There were contrasting results on the effects of fertilizer on growth and physiology of Kenaf in the dry (41 days) and wet season (64 days). Significant effects were only observed for diameter, height, leaf number and area during the wet season. Similar results were also found for biomass. The increasing trends with increasing the rates of fertilizer were observed in the wet season for growth and biomass parameters. The correlation analyses between total aboveground biomass with diameter and height were more pronounced in the wet season. AGR, Journal of Agricultural Science 122RGR and E G calculated from the differences between the dry and wet season readings for aboveground biomass showed that the higher rate of fertilizer recorded the higher values of AGR and RGR. However, no trend was observed for E G .

The present study was aimed at determining the potential in the uptake and translocation of essential trace elements by Amaranthus hybridus L. seedlings and the effects of added 0.0025M DTPA as a bioremediation technology to increase the contents of trace elements in edible parts. Four week old Amaranthus hybridus L. seedlings were transplanted in hydroponic solution treated with copper and zinc and then monitored in a greenhouse for 72 hr where significant changes in fresh weights were observed. The study was divided into two experiments first batch contains chelate and second batch contain unchelated treatments in three different combination of copper, zinc and Cu/Zn treatments. Cu2+ was restricted in the roots and no significant changes (p>0.05) in the accumulation of Cu2+ was observed with respect to addition of DTPA to different concentration compared to unchelated treatments. However, accumulation and transportation of Zn2+ from roots to shoots was increased significantly (p<0.05) to 2-3 fold after DTPA application compared to unchelated treatments as it helped to increase the metal bioavailability. Furthermore, in Cu/Zn combination, unchelated Cu2+ was found to accumulate more when compared to the chelated with the same Cu2+ concentration. Likewise, unchelated Zn2+ was significantly translocated as compared with chelate-assisted treatments of same zinc concentration. This indicates that in the presence of copper, zinc uptake was favorably translocated. Translocation factor was calculated to find relation with metal uptake in Amaranth hybridus L. seedlings. Keywords: Essential elements, DTPA amendment, hydroponic, Amaranthus hybridus L.

This research work was carried out to investigate the effects of ethylene diamine disuccinate (EDDS) on the absorption of cadmium and lead by hydroponically grown lettuce (Lactuca sativa L.). Samples were prepared through digestion (dry ashing) method and the analytes quantitatively analyzed using Atomic Absorption Spectrophotometric (AAS) technique. The effects of EDDS on Pb2+ and Cd2+ uptake by lettuce (Lactuca sativa L.) seedlings replanted in hydroponic solutions for 72 hr in a greenhouse were investigated. Two months old seedlings were exposed to various doses of Pb2+ and Cd2+ at constant concentration of EDDS. For unchelated treatments, increase in concentrations of Pb2+ and Cd2+ in the solution increases the uptake by the plants relative to control.  Pb2+ contents in the roots showed more accumulation than in shoots (p<0.05) while Cd2+ content in the shoots was higher than in roots.  Addition of 0.0025M EDDS to the solutions of Pb2+ and Cd2+ inhibits the uptake of the metal ions at the following concentrations (0.0025, 0.005 and 0.0075 mg/L) when compared to unchelated treatments of same concentrations. At 0.025 mg/L of Pb2+ and Cd2+, chelation substantially enhances their uptakes in both shoot and root of the plant (p<0.05).  Compared to the unchelated treatments, chelation suppresses the translocation of Pb2+ and Cd2+ to the shoots of the plant (p<0.05), but there was a better translocation of Pb2+ (1.257) and Cd2+ (0.953) at 0.025 mg/L, thus indicating that, at very high concentration of the metals the plant was hyper-accumulator. For hydroponic solutions containing the combination of both metals; Pb2+ + Cd2+, Pb2+ uptake was more in the roots than in the shoots while Cd2+ content in the shoots showed more absorption than the roots for both chelated and unchelated treatments. Also, it was observed that chelation suppresses the uptake of Pb2+ and Cd2+ in the presence of one another by both root and shoot. Furthermore, increasing the concentrations of Pb2+ + Cd2+ in chelated treatments of hydroponic solutions results to a better translocation of Pb2+ while the translocation of Cd2+ to the shoot was enhanced. Generally, addition of EDDS to the hydroponic mixtures affected to a large extent the availability of Pb2+ and Cd2+ to the growing seedlings. Keywords: Ethylene diamine disuccinate, greenhouse, hydroponic solution, lettuce, metals.  

It is well described that under stress conditions many plant species accumulates proline as adaptive response to adverse conditions. In this study, eight weeks old Lactuca sativa L. seedlings were transplanted in nutrient solution containing various doses (0.000, 0.0025, 0.005, 0.0075, and 0.025mg/L) of Pb2+ and Cd2+ and constant concentration of EDDS (0.0025M).  The effects of these treatments of Pb2+, Cd2+, combination of Pb2+ + Cd2+and with or without EDDS (Ethylene  diamine disuccinate) were compared based on the level of stress induced to the seedlings. Free proline contents induced due to stress by uptake of Pb2+and Cd2+ were investigated in both unchelated and chelated treatment. The results obtained showed that the effect of increasing concentration of Pb2+ in hydroponic solution leads to decrease in the level of stress induced to the seedlings by EDDS while the lower the Cd2+ concentration in the hydroponic solution the more the level of stress induced by EDDS to the plant. The highest level of stress caused to the seedlings by unchelated and chelated Pb2+ solution are 68.294±5.642; 72.681±14.740 µmolg-1 respectively while that of Cd2+ are 28.962±8.703; 48.263±2.455 µmolg-1 respectively. From this, it is evident that Pb2+induced more stress to the plants than Cd2+ in the presence and absence of EDDS (p<0.05). Keywords: Proline, Ethylenediaminedisuccinic Acid (EDDS), Lead, Cadmium, Lettuce.

This study was carried out to assess the effects of EDTA on zinc and copper uptake in the hydroponically grown mint leaf (Mentha piperita L) as well as their translocation factors in both chelated and unchelated treatments. In the present work, effects of EDTA on Zn2+ and Cu2+ uptake by mint leaf (Mentha piperita L.) seedlings replanted in hydroponic solutions in a greenhouse were investigated. Two months old seedlings, were exposed to various doses of Zn2+ and Cu2+ (0, 0.0025, 0.005, 0.0075, and 0.025 mg/L) and constant concentration of EDTA (0.0025M).  For unchelated treatments, the effects of increasing concentrations of Zn2+ and Cu2+ in the solution increases the uptake by the plants relative to control.  Zn2+ contents in the shoots showed more accumulation than in the roots (p<0.05) and also Cu2+ content in the shoots was higher than in roots. Hence, for the chelated treatments i.e. addition of 0.0025M EDTA to the solutions of Zn2+ and Cu2+ inhibits their uptake in both shoot and root of the plant at (0.0025, 0.005, 0.0075 mg/L) when compared to the unchelated treatment of same concentration. But at 0.025 mg/L, chelation does not have much effect on the Zn2+ and Cu2+ uptakes in both shoot and root of the plant (p>0.05) as the uptake in both chelated and unchelated treatments was almost constant. Hence, chelation inhibits translocation of Zn2+ and Cu2+ to the shoots of the plant at highest concentration of zinc and copper in the solution. Keywords: Ethylene diamine tetraacetic acid, chelation, mint leaf, hydroponic, greenhouse.