Plant cells from an onion bulb lack chloroplasts because this part of the plant grows below ground, making it incapable of absorbing the light needed to photosynthesize. Most subterranean root and bulb structures in plants do not have chloroplasts for this reason.
Although cells at the very top of the bulb that peek through the soil may develop chloroplasts, the main function of these cells is to protect the plant against harmful pathogens in the soil and to store energy. These functions are made possible by the cell wall, cell membrane, cytoplasm, nucleus and large vacuum of the cell.
Light microscopy renders the nucleus of an onion cell visible at the edge of the cytoplasm. The vacuole is visible in the middle of the cell. This vacuole is transparent in the cells of white onions, making them invisible to light microscopy unless they are stained. Cells of red onions are naturally pigmented and do not require the addition of a staining agent.
The best samples for viewing through a light microscope are prepared from thin slices of small, firm onions. The orientation of the cells under a light microscope can increase or decrease their visibility. The more light that is allowed to pass through, the better the resolution becomes.Learn More
The purple velvet plant, Gynura aurantiaca, is a plant with toothed, velvety leaves that's often used as a houseplant. The leaves are actually green but have soft, purple hairs that give them their distinctive color. Clusters of orange flowers that arrive in the spring and summer contrast with the color and texture of the leaves. Another name for this plant is the purple passion plant.Full Answer >
It takes from 3 to 12 months to grow an orchid from seed. However, it can take up to 10 years for the plant to start flowering.Full Answer >
During photosynthesis, chlorophyll absorb light energy that is used to convert carbon dioxide from the air and water from the soil into glucose. Oxygen is released as a by-product. Some glucose is used for respiration, while some is converted into insoluble starch.Full Answer >
Chloroplasts are the organelles found in plant cells that contain chlorophyll and undergo photosynthesis. The chlorophyll pigments found in the chloroplasts are the main pigments utilized in photosynthetic reactions.Full Answer >