Onion cells lack chloroplasts because the onion is part of the plant that is not involved in photosynthesis. The part of the plant eaten by humans is called the bulb, and it resides at the base of the plant. The bulb’s primary purpose is energy storage and holding the flower for the second growing season. Growing near the ground, the bulb is in poor position to collect sunlight.Know More
Photosynthesis is the process by which plants use sunlight, water, carbon dioxide and a chemical called chlorophyll, to create sugars. Chloroplasts are small organelles, located in some plant cells, that contain chlorophyll and enable photosynthesis. The onion is a photosynthetic plant, and it holds numerous chloroplasts in the leaves, which receive much more sunlight, but very few in other parts of the plant.
Onions are typically harvested at the end of their first growing season, after they have shed their leaves and become dormant. However, if left in the ground, a new stem and flower will erupt from within the onion bulb the following season. This can also happen to harvested onions that have been stored for a long period. Onions have been cultivated by humans for at least 7,000 years, and they are grown in a variety of flavors, colors and sizes.Learn More
Willow trees form a large portion of the genus Salix. The most common willow trees include the black willow (Salix negra), white willow (S. alba) and weeping willow (S. babylonica).Full Answer >
Curled, wilted or distorted leaves, along with dark or tarlike spots are common symptoms of dogwood anthracnose. Drought and winter injuries weaken trees, and the anthracnose fungus mostly attacks during the cool, wet spring and fall weather, but it can occur during any season.Full Answer >
Chloroplasts contain multiple structures, including the membrane envelope, stroma, grana, thylakoid membrane and chlorophyll. Choloroplasts are the organelles within plant cells where photosynthesis takes place.Full Answer >
Catnip, also called catmint, is a member of the mint family that is known to repel mosquitoes. A study headed by researchers from Iowa State University found that nepetalactone, an essential oil found in catnip, was 10 times more effective than DEET, a compound found in commercial insect repellents.Full Answer >