Tag: cryptograms

Chara is a streptophytic algae that grows underwater. It does not produce flowers and remains in a submerged stage.

Litmus solution is a purple dye, which is extracted from lichen, a plant belonging to the division Thallophyta, and is commonly used as an indicator. 
There are many other natural materials like red cabbage leaves, turmeric, coloured petals of some flowers such as Hydrangea, Petunia and Geranium, which indicate the presence of acid or base in a solution. These are called acid-base indicators or sometimes simply indicators.

Thallophyta: salient features are- most primitive and simple plants. They do not possess a vascular system. The plant body is not differentiated into stem roots and leaves. The whole plant body remains in the form of an undivided mass of cells called thallus. The mode of nutrition is photosynthetic, parasitic or saprophytic. They reproduce both sexually and asexually. Asexual reproduction usually reproduction takes place by spore formation. Fertilization is not followed by embryo formation. The division Thallophyta includes two major classes, algae and lichens. 

The eyespot or stigma is a photoreceptive organelle found in the flagellate of green algae like Chlamydomonas and some other unicellular photosynthetic organisms such as euglenoids. It allows the cells to sense light direction and intensity and respond to it by swimming either towards the light (positive phototaxis) or away from the light (negative phototaxis). A related response occurs when cells are briefly exposed to high light intensity, causing the cell to stop, briefly swim backward, then change swimming direction. Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis. Eyespots are the simplest and most common "eyes" found in nature, composed of photoreceptors and areas of bright orange-red pigment granules. Signals relayed from the eyespot photoreceptors result in alteration of the beating pattern of the flagella, generating a phototactic response.

Green algae have chloroplasts that contain chlorophyll a and b, giving them a bright green color, as well as the accessory pigments beta carotene and xanthophylls, in stacked thylakoids. The cell walls of green algae usually contain cellulose, and they store carbohydrate in the form of starch. The end products of photosynthesis in these green algae are starch and proteins.

The plant body consists of unbranched, uniseriate filaments. The cells of the filaments are arranged end to end. They are barrel-shaped or cylindrical in shape. The apical cell is somewhat rounded at its terminal end whereas, the basal cell is elongated and does not have chlorophyll. It is also called as the basal holdfast, which attaches the filament to the substratum.

During the process of photosynthesis, phytoplankton produces oxygen as a byproduct. Due to their vast and widespread populations, algae and cyanobacteria are responsible for approximately half of all the oxygen found in the ocean and in our atmosphere. During day time they float, due to the accumulation of oxygen. Whereas the reverse happens during the night, which is explained below.
In addition to providing food and oxygen for nearly all life on Earth, phytoplankton help to regulate inorganic carbon (carbon dioxide) in the atmosphere. During photosynthesis, carbon dioxide and water molecules are used to make sugar for energy. The process of incorporating inorganic carbon into organic carbon (glucose and other biologically useful compounds) is called carbon fixation and is part of the biological carbon pump.
As carbon fixation and oxygen production are part of the same process, the extent of phytoplanktons participation is on the same scale. Phytoplankton consumes a similar amount of carbon dioxide as all land plants combined. While phytoplankton can pull carbon dioxide from the atmosphere or the ocean, it will have a similar effect. Carbon dioxide that is taken from the water is replaced by carbon dioxide from the atmosphere.