Answer:Meristems are special regions in plants where active cell division takes place. They are responsible for the growth and development of the plant, including the production of new roots, stems, and leaves. Apical meristems are located at the tips of the roots and shoots and are responsible for primary growth, which leads to an increase in the length of the plant. Meristems are important because they allow plants to continually grow and adapt to their environment.
Tropisms are directional growth responses of plants to external stimuli. Two examples of tropisms are phototropism, which is the response to light, and gravitropism, which is the response to gravity. In phototropism, plants respond to light by bending towards the light source. In gravitropism, roots grow downwards in response to gravity, while stems grow upwards.
The main group of plant hormones is called "phytohormones" or "plant growth regulators." There are five main types of plant hormones: auxins, cytokinins, gibberellins, abscisic acid, and ethylene.
Plant hormones have a variety of functions, including controlling growth and development, regulating stress responses, and coordinating responses to external stimuli.
Auxin influences gene expression by promoting the expression of certain genes and suppressing the expression of others. Auxin can also activate or inhibit protein synthesis, leading to changes in cell growth and development.
Micropropagation is a technique used to rapidly propagate large numbers of plants from a small tissue sample. The technique involves growing the tissue in vitro, under sterile conditions, and providing the necessary nutrients and hormones for growth.
Micropropagation is done by taking a small tissue sample from a parent plant and placing it in a sterile environment. The sample is then grown in a nutrient-rich medium containing hormones that promote cell division and growth.
Micropropagation is done to quickly and efficiently produce large numbers of plants with desirable traits, such as disease resistance, improved growth, or higher yield.
External factors that can affect gene expression and flowering include light, temperature, humidity, and nutrient availability.
Phytochrome is a pigment that regulates plant responses to light. In short-day plants, phytochrome triggers flowering when the nights are longer than a critical length. In long-day plants, phytochrome triggers flowering when the nights are shorter than a critical length.
Pollination is the transfer of pollen from the male reproductive organ of a flower to the female reproductive organ of another flower.
Fertilization occurs when the sperm from the pollen grain fuses with the egg cell in the ovule, resulting in the formation of a zygote.
Seed dispersal is the process by which seeds are spread from the parent plant to new locations, allowing the plant to colonize new areas.
Flowering can be induced out of season by manipulating the light cycle or by treating the plant with chemicals that promote flowering.
Germination is the process by which a seed begins to grow into a new plant.
The conditions required for germination vary depending on the species, but typically include water, oxygen, and a suitable temperature.
Gibberellins are hormones that promote cell elongation and growth in plants. They are synthesized at the start of germination and are responsible for breaking down stored starches and releasing sugars to provide energy for growth.
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