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Shoot

About: Shoot is a research topic. Over the lifetime, 32188 publications have been published within this topic receiving 693348 citations.


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Journal ArticleDOI
TL;DR: The high metal accumulation by some cultivars of B. juncea suggests that these plants may be used to clean up toxic metal-contaminated sites in a process termed phytoextraction.
Abstract: A small number of wild plants which grow on metal contaminated soil accumulate large amounts of heavy metals in their roots and shoots This property may be exploited for soil reclamation if an easily cultivated, high biomass crop plant able to accumulate heavy metals is identified Therefore, the ability of various crop plants to accumulate Pb in shoots and roots was compared While all crop Brassicas tested accumulated Pb, some cultivars of Brassica juncea (L) Czern showed a strong ability to accumulate Pb in roots and to transport Pb to the shoots (1083 mg Pb/g DW in the roots and 345 mg Pb/g DW in the shoots) B juncea was also able to concentrate Cr{sup -6}, Cd, Ni, Zn, and Cu in the shoots 58, 52, 31, 17, and 7 fold, respectively, from a substrate containing sulfates and phosphates as fertilizers The high metal accumulation by some cultivars of B juncea suggests that these plants may be used to clean up toxic metal-contaminated sites in a process termed phytoextraction

1,445 citations

Journal ArticleDOI
TL;DR: An update on the effects of mineral deficiencies on the expression of genes involved in primary metabolism in the shoot, the evidence for increased carbohydrate concentrations and altered biomass allocation between shoot and root, and the consequences of these changes on the growth and morphology of the plant root system are presented.

1,022 citations

Journal ArticleDOI
TL;DR: The experiments show that adequate external concentrations of nitrogen and phosphorus are required by any part of the root system for optimal growth of laterals, but not axes, and possible mechanisms which compensate shoot growth when nutrients are supplied to only part of a root system, and agronomic implications are discussed.
Abstract: SUMMARY Barley plants were grown for 21 days in sand culture, continuously irrigated with nutrient solution. The rooting depth was divided into three compartments, one above another, such that different zones of the root system could be supplied with very low or high concentrations of a single inorganic nutrient, all other nutrients being maintained at a high concentration. Exposure of parts of the main seminal roots (axes) to high concentrations of phosphate caused a localized promotion of the initiation and subsequent extension of both first and second order laterals, compared with zones receiving very low concentrations of phosphate. This resulted in considerable modification to root form, but with only a small depression in shoot growth, compared with control plants receiving an ample supply to all parts of the root system. The extension of seminal axes was little affected by the concentration of phosphate to which they were exposed. Similar responses to those described for phosphate occurred with variation in concentration of nitrate or ammonium, but with potassium a localized supply promoted the growth of laterals to approximately the same extent as controls throughout the entire root system. The experiments show that adequate external concentrations of nitrogen and phosphorus are required by any part of the root system for optimal growth of laterals, but not axes. Possible mechanisms which compensate shoot growth when nutrients are supplied to only part of the root system, and agronomic implications, are discussed.

876 citations

Journal ArticleDOI
TL;DR: Information on the phylogenetic variation in shoot Si concentration may provide useful palaeoecological and archaeological information, and inform studies of the biogeochemical cycling of Si and those of the molecular genetics of Si uptake and transport in plants.

871 citations

Book ChapterDOI
TL;DR: In this paper, free-air CO2 enrichment (FACE) experiments have been conducted on several agricultural crops: wheat(Triticum aestivum L), perennial ryegrass (Lolium perenne), and rice(Oryza sativa L.) which are C3 grasses; sorghum (Sorghum bicolor (L.) Moench), a C4 grass; white clover (Trifolium repens), a c3 legume; potato (Solanum tuberosum L.), a C3
Abstract: Over the past decade, free-air CO2 enrichment (FACE) experiments have been conducted on several agricultural crops: wheat(Triticum aestivum L.), perennial ryegrass (Lolium perenne), and rice(Oryza sativa L.) which are C3 grasses; sorghum (Sorghum bicolor (L.) Moench), a C4 grass; white clover (Trifolium repens), a C3 legume; potato (Solanum tuberosum L.), a C3 forb with tuber storage; and cotton (Gossypium hirsutum L.) and grape (Vitis vinifera L.) which are C3 woody perennials. Using reports from these experiments, the relative responses of these crops was discussed with regard to photosynthesis, stomatal conductance, canopy temperature, water use, water potential, leaf area index, shoot and root biomass accumulation, agricultural yield, radiation use efficiency, specific leaf area, tissue nitrogen concentration, nitrogen yield, carbohydrate concentration, phenology, soil microbiology, soil respiration, trace gas emissions, and soil carbon sequestration. Generally, the magnitude of these responses varied with the functional type of plant and with the soil nitrogen and water status. As expected, the elevated CO2 increased photosynthesis and biomass production and yield substantially in C3 species, but little in C4, and it decreased stomatal conductance and transpiration in both C3 and C4 species and greatly improved water-use efficiency in all the crops. Growth stimulations were as large or larger under water-stress compared to well-watered conditions. Growth stimulations of non-legumes were reduced at low soil nitrogen, whereas elevated CO2 strongly stimulated the growth of the clover legume both at ample and under low N conditions. Roots were generally stimulated more than shoots. Woody perennials had larger growth responses to elevated CO2, while at the same time, their reductions in stomatal conductance were smaller. Tissue nitrogen concentrations went down while carbohydrate and some other carbon-based compounds went up due to elevated CO2, with leaves and foliage affected more than other organs. Phenology was accelerated slightly in most but not all species. Elevated CO2 affected some soil microbes greatly but not others, yet overall activity appears to be stimulated. Detection of statistically significant changes in soil organic carbon in any one study was impossible, yet combining results from several sites and years, it appears that elevated CO2 did increase sequestration of soil carbon. Whenever possible, comparisons were made between the FACE results and those from prior chamber-based experiments reviewed in the literature. Over all the data and parameters considered in this review, there are only two parameters for which the FACE- and chamber-based data appear to be inconsistent. One is that elevated CO2 from FACE appears to reduce stomatal conductance about one and a half times more than observed in prior chamber experiments. Similarly, elevated CO2 appears to have stimulated root growth relatively more than shoot growth under FACE conditions compared to chamber conditions. Nevertheless, for the most part, the FACE- and chamber-based results have been consistent, which gives confidence that conclusions drawn from both types of data are accurate. However, the more realistic FACE environment and the larger plot size have enabled more extensive robust multidisciplinary data sets to be obtained under conditions representative of open fields in the future high-CO2 world.

843 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20232,131
20224,637
2021953
20201,041
20191,064