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The cell wall is flexible during growth and has small pores called plasmodesmata that allow the exchange of nutrients and hormones between cells. [2] Many types of plant cells contain a large central vacuole, a water-filled volume enclosed by a membrane known as the tonoplast [3] that maintains the cell's turgor, controls movement of molecules ...
During winter dormancy, plant metabolism comes to a virtual standstill, due in part to low temperatures that slow chemical activity. [1] Dormancy is a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to ...
These interactions (whether it be plant-plant, animal-animal, predator-prey or plant-animal interactions) can be vital to the success and survival of populations and therefore species. Many species experience changes in life cycle development, migration or in some other process/behavior at different times in the season than previous patterns ...
This is a diagram of cell elongation in a plant. In sum, the acidity within the cell wall as a result of a high proton concentration in the cell wall. As a result,the cell wall becomes more flexible so that when water comes into the plant vacuole, the plant cell will elongate. This image shows the development of a normal plant.
[9] [10] These two cells are very different, and give rise to different structures, establishing polarity in the embryo. apical cell The small apical cell is on the top and contains most of the cytoplasm, the aqueous substance found within cells, from the original zygote. [11] It gives rise to the hypocotyl, shoot apical meristem, and ...
Above the species level, plant lineages clearly vary in their tendency for annuality or perenniality (e.g., wheat vs. oaks). On a microevolutionary timescale, a single plant species may show different annual or perennial ecotypes (e.g., adapted to dry or tropical range), as in the case of the wild progenitor of rice (Oryza rufipogon).
Map of average growing season length from "Geography of Ohio," 1923. A season is a division of the year marked by changes in weather, ecology, and the amount of daylight. The growing season is that portion of the year in which local conditions (i.e. rainfall, temperature, daylight) permit normal plant growth.
Summer is defined as the quarter of the year with the greatest insolation and winter as the quarter with the least. The solar seasons change at the cross-quarter days, which are about 3–4 weeks earlier than the meteorological seasons and 6–7 weeks earlier than seasons starting at equinoxes and solstices.