A. Asad

University of Agriculture Faisalabad

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R.W. Bell

Murdoch University

B. Dell

Murdoch University

F. P. C. Blamey

University of Queensland

Rizwan Rafique

Pir Mehr Ali Shah Arid Agriculture University

Longbin Huang

Jinan University

D. G. Edwards

University of Queensland

D. G. Edwards

University of Queensland

Mohammad Saleh

Birzeit University

T. N. Khan

Maharana Pratap University of Agriculture and Technology

Kadambot H. M. Siddique

University of Western Australia

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University of Queensland

University of Western Australia

The University of Tokyo

Murdoch University

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Commonwealth Scientific and Industrial Research Organisation

Brazilian Agricultural Research Corporation

University of Alberta

University of California, Davis

University of Georgia

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Screening for boron toxicity tolerance in chickpea (Cicer arietinum)

A. Asad R.W. Bell Kadambot H. M. Siddique T. N. Khan

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Effect of Zinc, Copper, Iron, Manganese and Boron on the Yield and Yield Components of Wheat Crop in Tehsil Peshawar

Pakistan Journal of Biological Sciences (2000)

A. Asad Rizwan Rafique

Iron levels

10.3923/pjbs.2000.1615.1620

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BORON REQUIREMENTS FOR SUNFLOWER AND WHEAT

Journal of Plant Nutrition (2002)

A. Asad

Abstract Plant species differ in their external and internal boron (B) requirements. The present research was conducted to establish the external and internal B requirements of sunflower (Helianthus annuus) and wheat (Triticum aestivum) at early vegetative growth. At low external B concentrations (≤ 0.13 μM), the growth of sunflower was severely depressed but by contrast the vegetative growth of wheat plants was free of B deficiency "symptoms. Sunflower plants achieved maximum growth at ≥ 1.2 μM B in solutions while wheat plants did so at ≥ 0.6 μM B. The critical B concentrations (mg kg−1 dry matter) in the youngest open leaf blades of sunflower and wheat plants were 19.7 and 1.2 at 10 days after transplanting (DAT), respectively. Acknowledgments

Helianthus annuus

Transplanting

10.1081/pln-120002967

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Plant and Soil (2002)

A. Asad F. P. C. Blamey D. G. Edwards

Helianthus annuus

Transplanting

10.1023/a:1019909130031

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Citations (66)

Applications in sustainable production

Communications in Soil Science and Plant Analysis (2000)

A. Asad R.W. Bell B. Dell

Abstract In conventional solution culture, differences in boron (B) concentration among plant parts and in distribution over time are often confounded with declining B supply. Using a B‐buffered solution system which maintained solutions at values that ranged from deficient to adequate, we examined B uptake and distribution in canola (Brassica napus L.) at 3 growth stages: 10 and 22 days after transplanting (DAT) and at early flowering (55 DAT). Boron concentrations in shoots and roots increased strongly with increasing solution B concentrations up to 1–2 μM B and then more weakly with increases in solution B above 2 μM B. At deficient to marginal external B concentrations, stems had higher B concentrations than leaf blades on Days 10 and 22 but not at adequate external B concentrations. In petioles, B concentration remained unchanged from Day 22 to 55 in most B treatments. With increasing external B concentrations, relative B content increased in leaf blades, decreased in roots, and generally remained unchanged in stems and petioles. Although the plants at low external B concentrations (≤ 0.55 μM) maintained vegetative growth they did not produce reproductive parts in contrast to the plants of adequate B. At the flowering stage, maximum B concentration was found in florets and growth of these plant parts was more sensitively depressed by low B than vegetative plant parts. At ≤ 0.41 μM external B concentration, reproductive growth was depressed compared to plants of ≥ 0.86 μM external B concentration, flowering was delayed for 6–8 days, and flowers aborted soon after bud burst.

Transplanting

Vegetative reproduction

10.1080/00103620009370578

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External Boron Requirements for Canola (Brassica napusL.) in Boron Buffered Solution Culture

Annals of Botany (1997)

A. Asad R.W. Bell B. Dell Longbin Huang

Quantitative relationships between external boron concentrations that could elicit boron deficiency and plant growth, boron uptake rate, and plant boron concentrations have not been previously investigated due to the lack of water culture systems that provide satisfactory control over solution boron concentrations. Two approaches were tested to buffer the boron concentrations in nutrient solutions: supplying different amounts of boron saturated resin Amberlite IRA 743 per unit solution volume; and loading the resin with boron at 1 to 100% of full saturation. Mean boron concentrations (μ M ) ranged from 0.17 to 2.85 and from 0.047 to 27.03 in the two approaches, respectively, and in individual pots with plants solutions remained constant in boron concentrations for at least 10 to 12 d. At solution boron concentrations from 0.04 to 0.3 μ M , canola ( Brassica napus L.) plants remained alive, but shoot and root growth was stunted and showed classical boron deficiency symptoms. Increasing solution boron concentrations progressively increased boron concentrations in shoots and roots. Boron concentrations in roots were less than one-third of those in lower shoots, and less than those in upper shoots, except in boron deficient plants. In boron buffered solutions, dry matter of canola at both 12 and 24 d increased with increasing solution boron concentration up to 0.54–0.87 μ M . With increasing solution boron concentrations up to 26.5 μ M there was no further increase in dry matter, and no detrimental effects on plant growth. At 0.04 μ M boron, plants absorbed no boron from solution. Increasing solution boron concentrations from 0.1 to 26.5 μ M increased relative boron uptake rates from 0.005 to 0.1 μmol g −1 root f.wt d −1 . Maximum root efficiency, defined as relative uptake rate divided by the solution boron concentration, was achieved at 0.04 to 0.3 μ M boron in solution. With increasing solution boron concentrations, relative uptake rates of calcium decreased from 248 to 10 μmol g −1 root f.wt. d −1 . The results suggest that boron specifically inhibits calcium absorption.

10.1006/anbo.1997.0408

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Adaptation Trials of Atriplex and Maireana Species and Their Response to Saline Waterlogged Conditions in Pakistan

Pakistan Journal of Biological Sciences (2001)

A. Asad

Utilization of salt affected wasteland by growing forage shrubs has enormous economic and environmental implication for developing countries like Pakistan, where approximately 6.3 million ha of the land is salt affected. Considering the importance of Atriplex and Maireana species, research has been conducted using their different species on the salt affected soils of Faisalabad. Most of Atriplex and Maireana species survived under the environmental conditions of Faisalabad and gave the good yield in the form of forage. Some of these species are woody and can be used for fuel purposes. Sixteen genotypes of Atriplex and Maireana were tested for their tolerance to waterlogging in order to identify halophytic fodder shrubs suitable for growth on secondary salt-affected and waterlogged farmland. The physiological and morphological responses of the species tested were typical of species with a generally poor tolerance to waterlogging. Despite this, some species (eg A. Amnicola) were surprisingly resistant, surviving up to five months of waterlogging at moderate salinity and high evapotranspirational demand. The most resistant species, A amnicola maintained higher transpiration rates, leaf water potentials and shoot extension rates than most other species during five weeks of waterlogging, and a return to control levels more quickly than other species after plots were drained. Although little morphological adaptation to waterlogged conditions was detected, a shallow and extensive lateral root system and the formation of many short aerenchymatous adventitious roots from procumbent branches appeared to advantage A. Amnicola in an environment highly heterogeneous in salinity and low in oxygen concentration. Shallow fibrous rooted species were quickly killed by waterlogging, although the procumbent branches of some individuals survived as clones if they developed adventitious roots.

Atriplex

10.3923/pjbs.2001.451.457

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Boron nutrition of sunflower crops

A. Asad F. P. C. Blamey D. G. Edwards

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External and internal boron requirements of plants using boron buffered solution culture

A. Asad

In soils and in conventional nutrient solutions, establishing the internal and external boron (B) requirements of plants is often confounded because the external B concentration changes during plant growth. On the other hand, the major problem of working with low B concentrations in conventional nutrient solutions is that these concentrations are quickly depleted as B is taken up by the plant roots. Hence in most conventional solution cultures, the initial B concentration is often very high to ensure adequate supply of B throughout an experiment. This research was carried out to develop a solution culture system in which the free B concentration would be buffered at constant concentrations, ranging from low to high. This developed B-buffered solution culture system was then tested as a means of determining the internal and external B requirements of different plant species. Further experiments were conducted to study the external and internal B requirements of plants at different growth stages, and to study distribution of B in different plant parts by using the above B-buffered solution culture system. The B specific resin, Amberlite IRA 743, which complexes H3BO3 on its Nmethyl glucamine functional groups, was chosen for this study because the B saturated resin maintained a realistic equilibrium B concentration in solution and there was no evidence that the resin had significant effects on plant growth other than in releasing and equilibrating B in the nutrient solution. The resin released nitrogen (N) into solution but, provided an adequate solution N supply was maintained, there were no indirect effects of the resin on plant growth apart from its control of B solution concentration. The B sorption capacity of the resin varied from 2.2 to 5.0 mg B/g resin. Boron saturated resin maintained an equilibrium solution B concentration of 46 μM when added at the rate of 2 g of resin to 1L of B-free triple deionised water. Plants grown in complete nutrient solution with B-saturated resin added at 1 g per litre of nutrient solution grew as well as plants grown in conventional nutrient solution containing 9.2 μM B and their shoots contained adequate B concentrations for growth. Glasshouse experiments were undertaken to establish buffered B concentrations ranging from deficient to adequate in nutrient solutions. Supplying different amounts of B saturated resin, Amberlite IRA 743, per unit solution volume; and loading the resin with B at 1 to 100 % of full saturation resulted in solution B concentrations (μM) ranging from 0.17 to 2.9 and from 0.05 to 27.0, respectively. The latter method was more effective in producing a wide range of B supply, from deficiency to adequacy. By this method critical external and internal B concentrations at vegetative growth of canola were 0.6 fjM B and 6-8 mg B kg dry weight, respectively. At solution B concentrations from 0.04 to 0.3 μm, canola (Brassica napus L.) plants remained alive but both shoot and root growth were stunted with classical B deficiency symptoms. Increasing solution B concentrations progressively increased B concentrations in shoots and roots. In roots, B concentrations were less than one-third of those in lower shoots and less than those in upper shoots, except in B-deficient plants. At 0.04 μM B, plants absorbed no B from solution. Increasing solution B concentrations from 0.1 to 26.5 μM increased relative B uptake rates from 0.005 to 0.1 μ mole g root fresh weight day . Maximum root efficiency, defined as relative uptake rate divided by the solution B concentration, was achieved at 0.04 to 0.3 μM B in solution. With increasing solution B concentrations, relative uptake rates of calcium decreased from 248 to 10 μ mole g-1 root fresh weight day-1. The results suggest that B specifically inhibited calcium absorption or accelerated calcium efflux. Canola was grown to flowering in a subsequent experiment to study the effect of external B concentration, established with B-loaded resin, on the distribution of B in plants and to investigate the external B concentrations for near maximum vegetative and reproductive growth. Mean B concentrations in B-buffered nutrient solutions ranging from 0.36 to 46.6 μM were achieved by loading B-specific resin at 4 to 100 % of full saturation. At low levels of B, the resin maintained constant B in nutrient solutions from Day 0 to 55. When relative growth rates for the periods 0-10, 10-22 and 22-55 DAT were related to mean external B concentration, the critical external B concentration for the growth period of 0-55 DAT remained unchanged with time and plant growth stage. Boron concentrations in shoots and roots increased strongly with increasing solution B concentrations up to 1-2 μM B and then more weakly with increases in solution B above 2 μM B. At deficient to marginal external B concentrations, stems had higher B concentrations than leaf blades on Days 10 and 22 but not at Day 55. Although the plants at low external B (< 0.45 μM) concentrations had some vegetative growth they did not produce reproductive parts compared to the plants with adequate B. At the flowering stage, maximum B concentration was found in florets and growth of these plant parts was more sensitively depressed by low B than vegetative plant parts. At 0.86 μM B in nutrient solutions, plants achieved maximum vegetative dry matter and flowered normally. Plants supplied with < 0.45 μM B produced no flowers or flowers were abnormal with aborted stamens and pistils. At 0.35 μMB, plants, whilst stunted, continued to produce vegetative dry matter though reproductive growth was completely suppressed. At flowering higher B concentrations occurred in the flowers (50.3 mg/kg dry weight) than in leaf (19.9 mg/kg dry weight), stem (19.0 mg/kg dry weight) or root (14.7 mg/kg dry weight). This study suggested that external B requirements for canola at the reproductive stage is 0.86 μM for maximum or near to maximum growth. External and internal B requirements of three plant species were studied using the B-buffered solution culture technique. In a glasshouse solution culture experiment, B concentrations were buffered with B saturated resin (Amberlite IRA 743); and loading the resin with B at 1 to 100 % of full saturation. Average B concentrations (μM) in nutrient solutions ranged from 0.04-28.3. The external and internal B requirements of a monocot (wheat, Triticum aestivum), a herbaceous dicot (sunflower) and a woody dicot (marri Corymbia calophylla) were examined using the buffered culture system. Plants were harvested after 10 and 20 days (wheat and sunflower) or 20 and 40 days (marri). At low external B (< 0.13 μM), growth of marri and sunflower was severely depressed, whereas the growth of wheat plants was only weakly depressed at 0.04 pM B in solutions. Where maximum dry weight of shoots was obtained, B concentrations (mg/kg) in leaf blades at the first harvest were 17.9, 19.7 and 1.2, for marri, sunflower and wheat, respectively. Results of this experiment suggested that the two dicotyledons marri and sunflower have higher external and internal B requirements than wheat. Increasing solution B from 0.05 to 28.5 μM increased relative B uptake rates from 0.43-1.02, 0.64-0.94 and 0.02-0.07 μ mole g-1 root dry weight day -1 in the case of marri, sunflower and wheat, respectively. Thus, the higher internal and external B requirements of sunflower and marri compared to wheat were supported by higher rates of B absorption. In conclusion, the B-buffered solution culture system developed in this study has considerable potential for B nutrition studies of plants. This system is robust and easy to establish. Whilst B-specific resin supplied B to canola till flowering stage at higher B loadings (> 16% of full B saturation of resin) it did not maintain constant B concentrations for more than 22 days growth. The length of time for which effective buffering of solution B was achieved appeared to vary with rate of biomass accumulation which, in turn, was a function of time of year and plant species. It is suggested that buffered B concentrations in nutrient solutions may be achieved for experiments of long duration either by increasing the amounts of resin per unit nutrient solution or replacing the B-specific resin after every 8-10 days.

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To study the boron requirements of plants using boron-specific resin (Amerlite IRA 743)

Agricultural Science (2000)

A. Asad

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