Table of Contents
- 1 What is pollen germination?
- 2 Why do pollen grains germinate?
- 3 Where do pollen grains germinate?
- 4 What does a pollen grain do?
- 5 How can you tell if pollen is viable?
- 6 How do you know if pollen is viable?
- 7 How many sperm does a mature pollen grain have?
- 8 How does the sperm in the pollen grain reach the egg?
- 9 Does sperm cell grows out of a pollen grain?
What is pollen germination?
Pollen germination is a function of both hydration speed and the speed at which the pollen tube tip can be organized to form a tube that emerges through the pollen wall (Heslop-Harrison & Heslop-Harrison, 1992; Hoedemaekers et al., 2015).
Why do pollen grains germinate?
Principle: Pollen grains germinate and form pollen tubes after they get deposited by the process of pollination on compatible stigma. Pollen tube, made up of cellulose, is an extension of the inner wall of pollen grain (intine.
Where do pollen grains germinate?
stigma
Pollen germination starts with the pollen grain landing on stigma. The cell of the pollen grain divides into two cells- one of these is smaller in size and called generative cell and bigger one is called tube cell. The intine grows out through the germ pore and form pollen tube.
What is pollen grain viability?
Pollen viability is the ability of pollen to effect fertilization and consequent development of fruit and seed; therefore fruit set and seed set form the most authentic test for pollen viability.
Where does germination of a pollen grains occur?
The top part is called stigma which has a sticky surface and is receptive to pollen grains. So the germination of pollen grains takes place on the stigma of the flower.
What does a pollen grain do?
Pollen in plants is used for transferring haploid male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the anther of a flower to the stigma of the same flower.
How can you tell if pollen is viable?
Pollen grains stained that orange or bright red color were counted as viable. In the second staining method, 1 g potassium iodide and 0.5 g iodine were dissolved in 100 mL distilled water for the IKI solution. Pollen viability counts were made five minutes after pollen was placed on an IKI solution.
How do you know if pollen is viable?
Pollen viability can be evaluated by: (1) staining techniques; (2) in vitro and in vivo germination tests; or (3) analyzing final seed set. The choice of method depends on the crop or species (Dafni and Firmage, 2000, Dafni et al., 2005).
What is the difference between pollen germination and seed germination?
Answer: Pollens are very different from seeds because they are fine and powdery. They contain the microgametophytes or the gametes (comparable to the sperm cells) of seed plants. Like ordinary seeds, pollens can also have a hard coating for the pollen grain to provide protection during movement (pollination).
Why are pollen grains important?
Pollen is essential for sexual reproduction of flowering plants and plants that produce cones. Each pollen grain contains male gametes necessary for fertilisation. The scientific study of living and fossilised pollen grains is known as palynology. This process of double fertilisation is unique to flowering plants.
How many sperm does a mature pollen grain have?
The pollen tube develops from the pollen grain to initiate fertilization; the pollen grain divides into two sperm cells by mitosis; one of the sperm cells unites with the egg cell during fertilization.
How does the sperm in the pollen grain reach the egg?
The sperm in the pollen grain must be delivered to the egg, located in the ovary. The pollen grain grows a tube from the stigma, through the style, and down to the ovary. When the tube finds and reaches the ovule, the tip of the tube bursts.
Does sperm cell grows out of a pollen grain?
Pollen is a powdery substance consisting of pollen grains which are male microgametophytes of seed plants, which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophytes during the process of their movement from the stamens to the pistil of flowering plants, or from the male cone to the female cone of coniferous plants.
What is inside each grain of pollen?
Pollen grains are microscopic structures that carry the male reproductive cell of plants. The inside of the grain contains cytoplasm along with the tube cell (which becomes the pollen tube) and the generative cell (which releases the sperm nuclei). The outer shell is made of two layers.