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Bernard Genty's light adapted measuring protocol ΔF/F M ’, or Y(II), is an effective and sensitive way to measure plant samples under ambient or artificial lighting conditions. [19] However, since Y(II) values also change with light intensity, one should compare samples at the same light intensity unless light stress is the focus of the ...
Under the light microscope, eyespots appear as dark, orange-reddish spots or stigmata. They get their color from carotenoid pigments contained in bodies called pigment granules. The photoreceptors are found in the plasma membrane overlaying the pigmented bodies.
The number of thylakoids and the total thylakoid area of a chloroplast is influenced by light exposure. Shaded chloroplasts contain larger and more grana with more thylakoid membrane area than chloroplasts exposed to bright light, which have smaller and fewer grana and less thylakoid area. Thylakoid extent can change within minutes of light ...
Thylakoid structures Scanning transmission electron microscope (STEM) imaging of thylakoid membranes 10-nm-thick STEM tomographic slice from a lettuce chloroplast. Grana stacks are interconnected by unstacked stromal thylakoids, called stroma lamellae .
In another approach to studying photosynthesis, light-absorbing pigments such as chlorophyll can be extracted from chloroplasts. Like so many important biological systems in the cell, the photosynthetic system is ordered and compartmentalized in a system of membranes. [9] Isolated chloroplasts from spinach leaves, viewed under light microscope
The morphological similarity between chloroplasts and cyanobacteria was first reported by German botanist Andreas Franz Wilhelm Schimper in the 19th century [192] Chloroplasts are only found in plants and algae, [193] thus paving the way for Russian biologist Konstantin Mereschkowski to suggest in 1905 the symbiogenic origin of the plastid. [194]
Two sections of chloroplast flow are observed with the aid of a microscope. These sections are arranged helically along the longitudinal axis of the cell. [8] In one section, the chloroplasts move upward along one band of the helix, while in the other, the chloroplasts move downwardly. [8] The area between these sections are known as ...
In Porphyridium and in Chlamydomonas, there is a single highly conspicuous pyrenoid in a single chloroplast, visible using light microscopy. By contrast, in diatoms and dinoflagellates, there can be multiple pyrenoids. The Chlamydomonas pyrenoid has been observed to divide by fission during chloroplast division.