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Georgios Liakopoulos Varvara Psaroudi Sotiria Stavrianakou Dimosthenis Nikolopoulos George Karabourniotis 《植物养料与土壤学杂志》2012,175(2):189-195
Root active uptake and remobilization of boron (B) have been accepted as mechanisms contributing to nutrient efficiency under low supply of boron. Here, we examined the existence of these mechanisms in eggplant (Solanum melongena L.) supplied either with luxury (100 μM, B+) or low (7.5 μM, B–) B in the growth medium via semihydroponic cultivation. Boron treatment was marginally not limiting growth thus avoiding side‐effects and impairment of acclimation mechanisms of plants. The induction of a B‐concentrating mechanism was evident in the roots as B concentration in the xylem sap was only decreased by 23% in B– compared to B+ plants, i.e., B– roots concentrated B by a factor of 2.7 relative to the external solution. Leaf B concentration in the B– treatment decreased by 33% and 40% in young fully expanded and mature leaves, respectively. Larger differences were observed in the soluble B fraction that decreased by 65% in mature leaves. However, both total and soluble B concentrations in developing leaves were almost equal for both treatments exhibiting a pattern commonly observed in B‐remobilizing plants. On the other hand, amounts of B export in the phloem sap were small compared to other species in which B is highly mobile. The B export rate from source leaves was slightly increased under low B supply while that of sucrose was not affected. We conclude that the root concentrating mechanism contributes to the alleviation of B deficiency in eggplant under low B supply while B remobilization may also contribute to a lower degree. 相似文献
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Anna Gebruk Polina Mikhaylyukova Maria Mardashova Varvara Semenova Lea-Anne Henry Nikolay Shabalin Bhavani E. Narayanaswamy Vadim Mokievsky 《水产资源保护:海洋与淡水生态系统》2021,31(1):112-125
- The Atlantic walrus, Odobenus rosmarus rosmarus, forms a herd of nearly 4,000 heads in the Pechora Sea (south-eastern Barents Sea). The Near Threatened status of O. rosmarus rosmarus and the relative isolation of the Pechora Sea population, as well as the potential impacts of human activities in the area, make it important to characterize key habitats, including feeding grounds, in order to protect the species.
- The aim of the present study was to integrate multiple sources of environmental and biological data collected by satellite telemetry, remotely operated vehicle (ROV), and benthic grab sampling to examine the distribution and diversity of benthic foraging resources used by walrus in the Pechora Sea.
- Analysis of satellite telemetry data from seven males tagged on Vaigach Island helped to identify areas of high use by walruses near haulout sites on Matveev and Vaigach islands, and in between. Field data were collected from those feeding grounds in July 2016 using ROV video recordings and bottom grab sampling. Analysis of 19 grab stations revealed a heterogeneous macrobenthic community of 133 taxa with a mean biomass of 147.11 ± 7.35 g/m2. Bivalve molluscs, particularly Astarte borealis, Astarte montagui, and Ciliatocardium ciliatum, dominated the overall macrobenthic biomass, making up two-thirds of the total.
- Analysis of 16 ROV video transects showed high occurrences of mobile benthic decapods (3.03 ± 2.74 ind./min) and provided the first direct evidence that areas actively used by walrus in the Pechora Sea overlap with the distribution of the non-native omnivorous snow crab, Chionoecetes opilio.
- Integrating multiple data sources provides an early foundation for the kinds of ecosystem-based approaches needed to improve Pechora Sea resource management and to underpin Russia’s nascent marine spatial planning initiatives. Factors that need to be considered in marine spatial planning include impacts on benthic feeding grounds from offshore oil and gas development and the spread of the snow crab.
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The determinants of saprotrophic or predatory modes of the nematophagous fungus Arthrobotrys oligospora were investigated in soil microcosms and on solid nutrient media. A sterilized soil amended with 1% w/w alfalfa meal (C:N=32) and inoculated with conidia of A. oligospora, showed lower mycelium biomass and higher specific rate of conidia production in the presence of the bacterivorous nematode Caenorhabditis elegans than in its absence. As few as 10 nematodes g−1 soil were sufficient to enhance spore formation by the vegetative mycelium. Given that the fungus was not limited by available carbon and nitrogen, this indicates that nematodes provide essential growth factors regulating the development of A. oligospora. Carbon mineralisation by A. oligospora, measured as the rate of CO2 production, was found to be 25–35% lower in the presence of 20–60 C. elegans g−1 soil compared to soil without nematodes. This showed that A. oligospora had lower saprotrophic activity in the predaceous phase. Trap formation and nematophagous activity of A. oligospora were observed only where conidia were inoculated on nutrient poor medium (water agar), on low-nitrogen medium (Yeast Carbon Base agar) or on medium containing no amino-acids or vitamins (Czapek-Dox agar). A. oligospora did not form trapping structures when grown on nutrient-rich media containing three amino-acids (l-histidine monohydrocloride, dl-methionine and dl-tryptophan) and vitamins (biotin, calcium pantothenate, folic acid, inositol, niacin, p-aminobenzoic acid, pyridoxine hydrochloride, riboflavine, thiamine hydrochloride). It is concluded that predaceous behaviour of A. oligospora can be regulated either by nitrogen sources or by physiologically active compounds (amino-acids or vitamins) present in nematodes. 相似文献
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Georgios C. Koubouris Varvara I. Maliogka Kostadinos Efthimiou Nikolaos I. Katis Miltiadis D. Vasilakakis 《Journal of General Plant Pathology》2007,73(5):370-373
The effectiveness of in vitro thermotherapy (explants at 35–37°C for 20 days) in obtaining propagating material of apricot
(Prunus armeniaca L.) cultivar Bebecou that is free of Plum pox virus (PPV) was compared to a conventional heat treatment technique (potted plants at 30–35°C for 8 weeks). An improved protocol
for in vitro thermotherapy was combined with shoot tip culture. The protocol is 5.8 times more effective than conventional
thermotherapy while taking half the time and is likely to have a high commercial impact for nurseries. 相似文献
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