Search results
Results from the WOW.Com Content Network
The stigma (from Ancient Greek στίγμα, stigma, meaning mark or puncture) is usually found at the tip of the style, the portion of the carpel(s) that receives pollen (male gametophytes). It is commonly sticky or feathery to capture pollen. The word "pistil" comes from Latin pistillum meaning pestle.
The stigma, together with the style and ovary (typically called the stigma-style-ovary system) comprises the pistil, which is part of the gynoecium or female reproductive organ of a plant. The stigma itself forms the distal portion of the style, or stylodia, and is composed of stigmatic papillae , the cells of which are receptive to pollen.
The two adjacent petals, the wings, surround the two bottom petals. The two bottom petals are fused together at the apex (remaining free at the base), forming a boat-like structure called the keel. The stamens are always ten in number, and their filaments can be fused in various configurations, often in a group of nine stamens plus one separate ...
g) Bacteria and bacterial filaments. h, i) Different bacterial individuals showing great varieties of shapes and morphological features. [33] Mycorrhizal fungi are abundant members of the rhizosphere community, and have been found in over 200,000 plant species, and are estimated to associate with over 80% of all plants. [34]
What characterizes an actinorhizal plant is the symbiotic relationship it forms with the bacteria Frankia, [9] in which they infect the roots of the plant. This relationship is what is responsible for the nitrogen-fixation qualities of the plants, and what makes them important to nitrogen-poor environments. [10]
Klebsiella bacteria tend to be rounder and thicker than other members of the family Enterobacteriaceae. They typically occur as straight rods with rounded or slightly pointed ends. They can be found singly, in pairs, or in short chains. Diplobacillary forms are commonly found in vivo. [6]
An archegonium (pl.: archegonia), from the Ancient Greek ἀρχή ("beginning") and γόνος ("offspring"), is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamete. The corresponding male organ is called the antheridium. The archegonium has a long neck canal or ...
The host plant provides the bacteria with amino acids so they do not need to assimilate ammonia. [5] The amino acids are then shuttled back to the plant with newly fixed nitrogen. Nitrogenase is an enzyme involved in nitrogen fixation and requires anaerobic conditions. Membranes within root nodules are able to provide these conditions.