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Proteoid Roots (proteoid + root)
Selected AbstractsInteractions between atmospheric CO2 concentration and phosphorus nutrition on the formation of proteoid roots in white lupin (Lupinus albus L.)PLANT CELL & ENVIRONMENT, Issue 8 2002C. D. Campbell Abstract Atmospheric [CO2] affects photosynthesis and therefore should affect the supply of carbon to roots. To evaluate interactions between carbon supply and nutrient acquisition, the [CO2] effects on root growth, proteoid root formation and phosphorus (P) uptake capacity were studied in white lupin (Lupinus albus L.) grown hydroponically at 200, 410 and 750 µmol mol,1 CO2, under sufficient (0·25 mm P) and deficient (0·69 µm P) phosphorus. Plant size increased with increasing [CO2] only at high P. Both P deficiency and increasing [CO2] increased the production of proteoid clusters; the increase in response to increased [CO2] was proportionally greater from low to ambient [CO2] than from ambient to high. The activity of phosphoenol pyruvate carboxylase in the proteoid root, the exudation of organic acids from the roots, and the specific uptake of P increased with P deficiency, but were unaffected by [CO2]. Increasing [CO2] from Pleistocene levels to those predicted for the next century increased plant size and allocation to proteoid roots, but did not change the specific P uptake capacity per unit root mass. Hence, rising [CO2] should promote nutrient uptake by allowing lupins to mine greater volumes of soil. [source] Low molecular weight organic acids and fatty acids in root exudates of two Lupinus cultivars at flowering and fruiting stagesPHYTOCHEMICAL ANALYSIS, Issue 5 2001J. A. Lucas García Abstract Low molecular weight organic acids (LOAs) and fatty acids in root exudates of two lupin cultivars, Lupinus albus cv. Multolupa and L. luteus cv. Tremosilla, were determined at flowering and fruiting stages. LOAs were analysed by capillary electrophoresis. Acetic and citric acids were the most abundant, especially the latter in L. luteus at the flowering stage (5922.79,µg/g dry root). The significant decrease in acid content of both cultivars from flowering to fruiting stages was also striking. The highest levels of acetic acid were detected in L. luteus at fruiting stage (1542.03,µg/g dry root). The significant citrate production in L. luteus could be related to the low phosphorus concentration in the studied soils but not to proteoid roots, which were detected only in L. albus. The source of the LOAs detected in these exudates is also discussed, since they may be produced either by the plant or by the associated rhizobacteria. The profile of phospholipid fatty acids was determined by high-resolution GC. A high level of 18:2,6 (a fatty acid specific to fungi) was found in exudates of L. luteus (a mycorrhizal plant) in contrast to L. albus (a non-mycorrhizal plant). Copyright © 2001 John Wiley & Sons, Ltd. [source] Interactions between atmospheric CO2 concentration and phosphorus nutrition on the formation of proteoid roots in white lupin (Lupinus albus L.)PLANT CELL & ENVIRONMENT, Issue 8 2002C. D. Campbell Abstract Atmospheric [CO2] affects photosynthesis and therefore should affect the supply of carbon to roots. To evaluate interactions between carbon supply and nutrient acquisition, the [CO2] effects on root growth, proteoid root formation and phosphorus (P) uptake capacity were studied in white lupin (Lupinus albus L.) grown hydroponically at 200, 410 and 750 µmol mol,1 CO2, under sufficient (0·25 mm P) and deficient (0·69 µm P) phosphorus. Plant size increased with increasing [CO2] only at high P. Both P deficiency and increasing [CO2] increased the production of proteoid clusters; the increase in response to increased [CO2] was proportionally greater from low to ambient [CO2] than from ambient to high. The activity of phosphoenol pyruvate carboxylase in the proteoid root, the exudation of organic acids from the roots, and the specific uptake of P increased with P deficiency, but were unaffected by [CO2]. Increasing [CO2] from Pleistocene levels to those predicted for the next century increased plant size and allocation to proteoid roots, but did not change the specific P uptake capacity per unit root mass. Hence, rising [CO2] should promote nutrient uptake by allowing lupins to mine greater volumes of soil. [source] Comparison of the nutrient ecology of coastal Banksia grandis elfinwood (windswept shrub-like form) and low trees, Cape Leeuwin-Naturaliste National Park, Western AustraliaAUSTRAL ECOLOGY, Issue 3 2003KENNETH A. BARRICK Abstract Trees growing along windy coasts often have canopies that are greatly reduced in size by the sculpting effects of wind and salt spray. Trees with environmentally reduced stature are called elfinwood (windswept shrub-form or krummholz) and are ecologically important because they represent outposts growing at the limit of tree success. The purpose of this study was to assess if Banksia grandis elfinwood growing at Cape Leeuwin had a different nutrient status than normal low-form (LF) trees growing nearby, and if nutrient deficiencies, toxicities and/or imbalances were among the limiting factors imposed on elfinwood. The concentrations of N, P, K, Ca, Mg, Na, Cl,, Fe, Mn, Zn, Cu, Mo and B were analysed for mature green foliage, immature foliage, foliage litter, flowers and soil. When the elfinwood and LF trees were compared, the foliar nutrient status was generally similar, except that elfinwood foliage had significantly higher mean concentrations of N, Zn and Cu, while LF trees had higher Fe and Mn contents. Many nutrients were conserved before leaves were shed in both elfinwood and LF trees, including N, P, K, Na, Cl,, Mn and Cu (LF trees also conserved Ca and Mg). However, elfinwood and LF tree-litter contained significantly higher Fe concentrations than green foliage (elfinwood litter also had higher levels of Mg and B). It is tempting to suggest that the translocation of Fe into leaves before they were shed is a regulation mechanism to prevent Fe toxicity, or imbalance in the Fe : Mn ratio. Proteoid roots strongly acidify the soil to mobilize P, which also chemically reduces Fe+3 to plant-available Fe+2. The increased supply of Fe+2 in the rhizosphere, caused by the action of proteoid roots, might tend to defeat self-regulation of Fe uptake. It is possible that excess Fe accumulation in the plant might be regulated, in part, by exporting Fe into the leaves before they are shed. The nutrient status of B. grandis elfinwood is compared with mountain elfinwood of North America. The extreme habitat of coastal elfinwood provides many theoretical pathways for nutrient limitation, but B. grandis elfinwood at Cape Leeuwin does not appear to be nutrient deficient. [source] | ||||||||||