David Lohman Raffles Museum of Biodiversity, National University of Singapore Insects are the most abundant and diverse macroscopic, terrestrial animals on the planet, and their species richness and high rate of reproduction make them ideal subjects for investigations in ecology, evolution, and behavior. We will discuss the traits that characterize insects and learn to identify several of the most important orders and families.
Advanced Search Abstract Recent phylogenetic analyses confirm the monophyly of Orchidaceae as sister group to the remainder of Asparagales, and identify the sequence of early branching lineages in Orchidaceae.
Orchid seedling mycorrhiza OSM involving rhizoctonious fungi is distributed widely in all subfamilies, including the first branching ones, and its status as a founding event is thus supported.
OSM is recognized as one element in the character syndrome that distinguishes orchid biology, and we argue that OSM was the first to evolve.
We also discuss the possible evolutionary origins of OSM in Asparagales. The prevalent mycobionts suggest a derivation from a pathogenic relationship, and sister group comparison offers little support for derivation from other mycorrhizal relationships. A combination of in situ sowings and molecular identification of seedling mycobionts has established that a broad range of fungi besides rhizoctonious mycelia are presently involved in OSM, presumably evolving secondarily and often in parallel in different orchid clades.
Structural features and internal patterns of mycobiont behaviour appear to have remained largely the same, implying that OSM needs only minor physiological adjustment to accommodate new mycobionts.
These physiological mechanisms are so far largely unknown. The trophic versatility of the mycobionts and the apparently easy shifts could be a main factor in the ecological adaptability of orchids and proliferation of the family.
Despite an astounding variation in floral morphology, orchids can usually be immediately recognized by a combination of a few easily observable characters, particularly an inferior ovary, zygomorphic perianth, and a reduced androecium, which is at least partially fused with the style into a gynostemium.
However, the only character that is unique to orchids and shared by all orchids is the occurrence of a mycotrophic protocorm stage in their life cycle. Orchid seeds do not produce a normal monocot seedling but germinate into a rootless and acotyledonous conical to spherical body, in the beginning only a few mm long, which is heavily mycorrhized.
Subsequently, the term protocorm, originally used for a structure observed in young sporophytes of certain lycopods Treub,was adopted for this first seedling stage of orchids by Bernardwho emphasized the absence of a primary root as a defining characteristic of the orchid protocorm.
Abbreviations, terms and definitions as used in the present review Endophyte: Refers broadly to organisms that occur within living plant parts; in the context of orchid mycorrhiza, it often refers to fungi encountered in orchid roots, although with no known role as pathogens or symbionts.
Non-orchid dust seeds generally have some endosperm, and many have a radicle and even cotyledons. A relationship between two kinds of organisms in which both parts benefit to some extent, either by exchange of essential substances or other services. In mycorrhizal relationships, mutualism often refers to a transfer of photoassimilates in exchange for essential ions.2.
4. 5. 6 7 8 9 Effects of arbuscular mycorrhizal fungi,Glomus mosseae,Glomus versiforme,and their community(tranceformingnlp.come,tranceformingnlp.comorme and Glomus intraradices) on cold tolerance of ornamental plant Coleus blumei were investigated under pot tranceformingnlp.com result showed that the AM fungal inoculation could significantly increase leaf SOD activities,contents .
PDF | Mycorrhizal fungi colonize tree seedlings shortly after germination, and the nature of this relationship (mutualistic to parasitic) has been reported to .
Introduction to Biology Lab Manual Biological Sciences 2B University of California, Davis Cover photo: Chrysomelid beetles, Zygogramma tortuosa, feeding and mating on a plant.
Mycorrhizal association and influence on growth of Asian pigeonwings (Clitoria ternatea L.) - Free download as PDF File .pdf), Text File .txt) or read online for free. Clitoria ternatea L. is an excellent herbal medicinal plant. Arbusular Mycorrhizal fungal (AMF) colonization and biomass of three different tested conditions of Clitoria ternatea plant was investigated.
The plant – mycorrhizal fungi symbiosis is one of the most changes in the plant's growth performanceand,consequently,speciesco-existenceandcommu-nitystructure(Lovelocketal;Sebastianaetal),thereis in a greenhouse experiment.
Seedlings were planted in several.