Plant and Soil

Abbott, Lynette; Tang, Caixian; Reuter, Doug

doi: 10.1007/s11104-011-0969-6pmid: N/A

Lambers, Hans; Brundrett, Mark; Raven, John; Hopper, Stephen

doi: 10.1007/s11104-011-0977-6pmid: N/A

Ancient landscapes, which have not been glaciated in recent times or disturbed by other major catastrophic events such as volcanic eruptions, are dominated by nutrient-impoverished soils. If these parts of the world have had a relatively stable climate, due to buffering by oceans, their floras tend to be very biodiverse. This review compares the functional ecophysiological plant traits that dominate in old, climatically buffered, infertile landscapes (OCBILS) with those commonly found in young, frequently disturbed, fertile landscapes (YODFELs). We show that, within the OCBILs of Western Australia, non-mycorrhizal species with specialised root clusters predominantly occur on the most phosphate-impoverished soils, where they co-occur with mycorrhizal species without such specialised root clusters. In global comparisons, we show that plants in OCBILs, especially in Western Australia, are characterised by very low leaf phosphorus (P) concentrations, very high N:P ratios, and very high LMA values (LMA = leaf mass per unit leaf area). In addition, we show that species in OCBILs are far more likely to show P-toxicity symptoms when exposed to slightly elevated soil P levels when compared with plants in YODFELs. In addition, some species in OCBILs exhibit a remarkable P-resorption proficiency, with some plants in Western Australia achieving leaf P concentrations in recently shed leaves that are lower than ever reported before. We discuss how this knowledge on functional traits can guide us towards sustainable management of ancient landscapes.

Hinsinger, Philippe; Brauman, Alain; Devau, Nicolas; Gérard, Frédéric; Jourdan, Christophe; Laclau, Jean-Paul; Cadre, Edith; Jaillard, Benoît; Plassard, Claude

doi: 10.1007/s11104-011-0903-ypmid: N/A

New routes for improving soil nutrient efficiency are addressed, with a particular focus on breeding and ecological engineering options. Better mimicking natural ecosystems and exploiting plant diversity appears as an appealing way forward, on this long and winding road towards ecological intensification of agroecosystems.

Smith, F.; Smith, Sally

doi: 10.1007/s11104-011-0865-0pmid: N/A

Arbuscular mycorrhizal (AM) symbioses are widespread in land plants but the extent to which they are functionally important in agriculture remains unclear, despite much previous research. We ask focused questions designed to give new perspectives on AM function, some based on recent research that is overturning past beliefs. We address factors that determine growth responses (from positive to negative) in AM plants, the extent to which AM plants that lack positive responses benefit in terms of nutrient (particularly phosphate: P) uptake, whether or not AM and nonmycorrhizal (NM) plants acquire different forms of soil P, and the cause(s) of AM ‘growth depressions’. We consider the relevance of laboratory work to the agricultural context, including effects of high (available) soil P on AM fungal colonisation and whether AM colonisation may be deleterious to crop production due to fungal ‘parasitism’. We emphasise the imperative for research that is aimed at increasing benefits of AM symbioses in the field at a time of increasing prices of P-fertiliser, and increasing demands on agriculture to feed the world. In other words, AM symbioses have key roles in providing ecosystem services that are receiving increasing attention worldwide.

Pearse, Stuart

doi: 10.1007/s11104-011-0975-8pmid: N/A

Wang, XiaoJuan; Guppy, Chris; Watson, Laura; Sale, Peter; Tang, Caixian

doi: 10.1007/s11104-011-0901-0pmid: N/A

Cotton is inefficient in utilizing sparingly soluble P while wheat is efficient in mobilising AlPO 4 and white lupin is efficient in using hydroxyapatite. The superiority of wheat in AlPO 4 utilization may be related with its high root length density.

Boot, Claudia

doi: 10.1007/s11104-011-0958-9pmid: N/A

Chowdhury, Nasrin; Nakatani, Andre; Setia, Raj; Marschner, Petra

doi: 10.1007/s11104-011-0918-4pmid: N/A

Microbes in moderately saline soils may be able to utilise substrates released after multiple DRW events better than microbes in non-saline soil. However, at high EC (EC17.6), the low osmotic potential reduced microbial activity to such an extent that the microbes were not able to utilise substrate released after rewetting of dry soil.

Mommer, Liesje; Dumbrell, Alex; Wagemaker, C.; Ouborg, N.

doi: 10.1007/s11104-011-0962-0pmid: N/A

Haling, Rebecca; Simpson, Richard; McKay, Alan; Hartley, Diana; Lambers, Hans; Ophel-Keller, Kathy; Wiebkin, Sue; Herdina, Sue; Riley, Ian; Richardson, Alan

doi: 10.1007/s11104-011-0846-3pmid: N/A

Molecular techniques present a new opportunity to study roots and their interactions in soil. Extraction and quantification of species-specific DNA directly from soil allows direct identification of roots in mixed swards reducing the need for labour-intensive methods to recover and identify individual roots. DNA was extracted directly from up to 0.5 kg of soil and the presence of individual species quantified using species-specific probes with quantitative real-time PCR. A range of plant and soil factors influenced the DNA content measured in roots and it was necessary to account for these influences when converting DNA amount to root mass. The utility of the method for quantitative root studies was demonstrated in an experiment to investigate the effect of lime on root growth of acid-soil resistant and sensitive perennial grasses grown together in an aluminium-toxic soil. The root mass of an acid-soil resistant species was unaffected by lime application, whereas that of an acid-soil sensitive species was restricted by soil acidity. Molecular techniques present a promising tool for quantification of root mass directly in soil and have applications for field studies involving mixed species of plants.