Autotoxicity of aquatic extracts from chrysanthemum and rhizosphere soil on photosynthesis in the same plant species

2009 ◽  
Vol 17 (2) ◽  
pp. 318-322
Author(s):  
Kai ZHOU ◽  
Wei-Ming GUO ◽  
Zhi-Fang WANG ◽  
Feng-Ge HAO
2020 ◽  
Vol 7 (2) ◽  
pp. 30-38
Author(s):  
Santhoshkumar S ◽  
Nagarajan N ◽  
Sree Priya S

In the present study to analyzed that the arbuscular mycorrhizal fungal spores in root colonization and spore population in rhizosphere soils samples in various medicinal at Paithal hills,Western Ghats of Kannur district, Kerala, India. Root and rhizosphere soil samples were collected during the month of August, 2018-March, 2019 from the surface to 30 cm depth as well as pH were also recorded. Totally 30 plant species belonging to 19 families were collected and identified. The present result showed arbuscular mycorrhizal spore population in the rhizosphere soil and root colonization of all the plant species. A total of 19 AM fungal spores were recovered from the rhizosphere soil samples in this study region. The Glomus was dominant had seen in rhizosphere soil samples in all the medicinal plant species. The maximum spore population was found in the rhizosphere soil samples of Mimosa pudica (590/100g of soil) which belongs to the family Mimosaceae and the lowest spore population was observed in the Terminalia bellirica 135/100g of soil) belongs to Combretaceae family. The highest  78 % AM fungal colonization was found in roots of Euphorbia hirta belongs to the family Euphorbiaceae. While the lowest 11 % AM fungal colonization was found in the root of Sida acuta belongs to the family Malvaceae.


2004 ◽  
Vol 70 (8) ◽  
pp. 4766-4774 ◽  
Author(s):  
Liz J. Shaw ◽  
Richard G. Burns

ABSTRACT Enhanced biodegradation in the rhizosphere has been reported for many organic xenobiotic compounds, although the mechanisms are not fully understood. The purpose of this study was to discover whether rhizosphere-enhanced biodegradation is due to selective enrichment of degraders through growth on compounds produced by rhizodeposition. We monitored the mineralization of [U-14C]2,4-dichlorophenoxyacetic acid (2,4-D) in rhizosphere soil with no history of herbicide application collected over a period of 0 to 116 days after sowing of Lolium perenne and Trifolium pratense. The relationships between the mineralization kinetics, the number of 2,4-D degraders, and the diversity of genes encoding 2,4-D/α-ketoglutarate dioxygenase (tfdA) were investigated. The rhizosphere effect on [14C]2,4-D mineralization (50 μg g−1) was shown to be plant species and plant age specific. In comparison with nonplanted soil, there were significant (P < 0.05) reductions in the lag phase and enhancements of the maximum mineralization rate for 25- and 60-day T. pratense soil but not for 116-day T. pratense rhizosphere soil or for L. perenne rhizosphere soil of any age. Numbers of 2,4-D degraders in planted and nonplanted soil were low (most probable number, <100 g−1) and were not related to plant species or age. Single-strand conformational polymorphism analysis showed that plant species had no impact on the diversity of α-Proteobacteria tfdA-like genes, although an impact of 2,4-D application was recorded. Our results indicate that enhanced mineralization in T. pratense rhizosphere soil is not due to enrichment of 2,4-D-degrading microorganisms by rhizodeposits. We suggest an alternative mechanism in which one or more components of the rhizodeposits induce the 2,4-D pathway.


Soil Research ◽  
2017 ◽  
Vol 55 (1) ◽  
pp. 58 ◽  
Author(s):  
Saikat Chowdhury ◽  
Ramya Thangarajan ◽  
Nanthi Bolan ◽  
Julianne O'Reilly-Wapstra ◽  
Anitha Kunhikrishnan ◽  
...  

The rhizosphere influences nutrient dynamics in soil mainly by altering microbial activity. The objective of this study was to evaluate the rhizosphere effect on nitrogen transformation in Australian native vegetation in relation to nitrification potential (NP). Microbial activity, NP, and nitrifiers (ammonia-oxidising bacteria, AOB) were compared between rhizosphere and non-rhizosphere soils of several Australian native vegetation under field conditions. These parameters were also measured with increasing distance from the rhizosphere of selected plant species using plant growth experiments. To examine the persistence of nitrification inhibitory activity of rhizosphere soil on non-rhizosphere soil, the soils were mixed at various ratios and examined for NP and AOB populations. The rhizosphere soil from all native vegetation (29 species) had higher microbial activity than non-rhizosphere soil, whereas 13 species showed very low NP in the rhizosphere when compared with non-rhizosphere soil. Nitrification potential and AOB populations obtained in the soil mixture were lower than the predicted values, indicating the persistence of a nitrification inhibitory effect of the rhizosphere soils on non-rhizosphere soils. In plant growth experiments the microbial activity decreased with increasing distance from rhizosphere, whereas the opposite was observed for NP and AOB populations, indicating the selective inhibition of nitrification process in the rhizosphere of the Australian native plants Scaevola albida, Chrysocephalum semipapposum, and Enteropogon acicularis. Some Australian native plants inhibited nitrification in their rhizosphere. We propose future studies on these selected plant species by identifying and characterising the nitrification inhibiting compounds and also the potential of nitrification inhibition in reducing nitrogen losses through nitrate leaching and nitrous oxide emission.


Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 3
Author(s):  
Hisashi Kato-Noguchi

Perennial herbaceous Fallopia is native to East Asia, and was introduced to Europe and North America in the 19th century as an ornamental plant. Fallopia has been spreading quickly and has naturalized in many countries. It is listed in the world’s 100 worst alien species. Fallopia often forms dense monospecies stands through the interruption of the regeneration process of indigenous plant species. Allelopathy of Japanese knotweed (Fallopia japonica), giant knotweed (Fallopia sachalinensis), and Bohemian knotweed (Fallopia x bohemica) has been reported to play an essential role in its invasion. The exudate from their roots and/or rhizomes, and their plant residues inhibited the germination and growth of some other plant species. These knotweeds, which are non-mycorrhizal plants, also suppressed the abundance and species richness of arbuscular mycorrhizal fungi (AMF) in the rhizosphere soil. Such suppression was critical for most territorial plants to form the mutualism with AMF, which enhances the nutrient and water uptake, and the tolerance against pathogens and stress conditions. Several allelochemicals such as flavanols, stilbenes, and quinones were identified in the extracts, residues, and rhizosphere soil of the knotweeds. The accumulated evidence suggests that some of those allelochemicals in knotweeds may be released into the rhizosphere soil through the decomposition process of their plant parts, and the exudation from their rhizomes and roots. Those allelochemicals may inhibit the germination and growth of native plants, and suppress the mycorrhizal colonization of native plants, which provides the knotweeds with a competitive advantage, and interrupts the regeneration processes of native plants. Therefore, allelopathy of knotweeds may contribute to establishing their new habitats in the introduced ranges as invasive plant species. It is the first review article focusing on the allelopathy of knotweeds.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1028
Author(s):  
Hisashi Kato-Noguchi ◽  
Denny Kurniadie

Lantana camara L. (Verbenaceae) is native to tropical America and has been introduced into many other countries as an ornamental and hedge plant. The species has been spreading quickly and has naturalized in more than 60 countries as an invasive noxious weed. It is considered to be one of the world’s 100 worst alien species. L. camara often forms dense monospecies stands through the interruption of the regeneration process of indigenous plant species. Allelopathy of L. camara has been reported to play a crucial role in its invasiveness. The extracts, essential oil, leachates, residues, and rhizosphere soil of L. camara suppressed the germination and growth of other plant species. Several allelochemicals, such as phenolic compounds, sesquiterpenes, triterpenes, and a flavonoid, were identified in the extracts, essential oil, residues, and rhizosphere soil of L. camara. The evidence also suggests that some of those allelochemicals in L. camara are probably released into the rhizosphere soil under the canopy and neighboring environments during the decomposition process of the residues and as leachates and volatile compounds from living plant parts of L. camara. The released allelochemicals may suppress the regeneration process of indigenous plant species by decreasing their germination and seedling growth and increasing their mortality. Therefore, the allelopathic property of L. camara may support its invasive potential and formation of dense monospecies stands.


2018 ◽  
Vol 48 (11) ◽  
pp. 1398-1405 ◽  
Author(s):  
Xiaoqin Dai ◽  
Xiaoli Fu ◽  
Liang Kou ◽  
Huimin Wang ◽  
Clinton C. Shock

Rhizosphere soil C:N:P stoichiometry is useful for identifying the linkage of plant species and soil nutrients, which can be particularly helpful for understory vegetation management of forest ecosystems. There has been limited research on rhizosphere soil stoichiometry, especially for co-existing overstory and understory plant species. We investigated the bulk and rhizosphere soil C:N:P stoichiometry of dominant overstory trees and understory shrubs (Adinandra millettii, Eurya muricata, and Loropetalum chinense) in Pinus massoniana Lamb., Pinus elliottii Engelm., and Cunninghamia lanceolata (Lamb.) Hook. plantations in subtropical China. Rhizosphere soil C, N, and P concentrations and ratios increased significantly compared with bulk soil, and those of overstory trees were higher than those of understory shrubs with the exception of L. chinense. Rhizosphere soil C:N, C:P, and N:P of L. chinense were not significantly different with those of overstory trees but were higher than those of A. millettii and E. muricata. Soil pH significantly influenced the profiles produced by soil C, N, and P concentrations and their stoichiometries. This study indicated that the difference in nutrient status between overstory trees and understory shrubs was related to shrub species, in which soil pH was the dominant driving factor. Understory shrub species should be considered in plantation management to reduce resource competition among species.


2014 ◽  
Vol 35 (1) ◽  
pp. 3-23 ◽  
Author(s):  
Mariusz Tadych ◽  
Janusz Błaszkowski

The occurrence of arbuscular mycorrhizal fungi (AMF) associated with 19 plant species from 12 families growing in the Brda river valley in the Tuchola Forests is presented. The most frequently investigated plans were those from the families <i>Cupressaceae</i> and <i>Plantaginaceae</i>. Examination of trap cultures established from rhizosphere soil-root mixtures of the plans sampled revealed 20 described species of AMF, two undescribed <i>Glomus</i> spp., and three species of the genus <i>Glomus</i> that were difficult to recognize. The dominating AMF were members of the genus <i>Glomus</i>. Among the AMF found, <i>G. claroideum</i> was present, a species recorded for the first time in Poland. The distribution in Poland and in the world of the AMF encountered is shown.


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