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Pollen tube growth is toward eggs of the same species as the pollen. Intraspecific signaling helps fertilize egg and sperm of the same species. The signaling in the style is important as pollen tubes can grow without the presence of an embryo sac with just interaction with the style.
If the pollen is compatible it will germinate and begin to grow. [5] The ovary releases chemicals that stimulates a positive chemotropic response from the developing pollen tube. [6] In response the tube develops a defined tip growth area that promotes directional growth and elongation of the pollen tube due to a calcium gradient. [5]
Pollen itself is not the male gamete. [4] It is a gametophyte, something that could be considered an entire organism, which then produces the male gamete.Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive) cell.
When pollen competition occurs, the competitive ability is determined by differences between tube growth rate or the time it takes for germination to occur. [4] Pollen completion is increased when pollen is not limiting and when pollen is in abundance relative to the number of ovules present in the ovary, but this does not guarantee pollen ...
Tomato and tobacco pollen tubes grew towards the positive electrode for constant electric fields higher than 0.2 V/cm. [4] Agapanthus umbelatus pollen tubes grow towards the nearest electrode when a constant electric field of 7.5 V/cm is applied. [11] Another report states that pollen tubes do not change growth direction under AC electric ...
The protons are effluxed at a region on the sides of the tube that corresponds to the location of the intracellular alkaline band. [71] Energy is required for pollen tube growth [72] and an H +-ATPase may mediate the efflux. Hepler has shown that the magnitude of the intracellular calcium and proton gradients and the extracellular fluxes of ...
Bee pollen, a natural substance ... can affect breast size but there is no indication that bee pollen has a direct impact on breast tissue growth or size," says Haddad. But fans of the supplement ...
Hydrolytic enzymes are secreted by the pollen tube that digest the female tissue as the tube grows down the stigma and style; the digested tissue is used as a nutrient source for the pollen tube as it grows. During pollen tube growth towards the ovary, the generative nucleus divides to produce two separate sperm nuclei (haploid number of ...