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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]
Some plants use the control of pollen germination as a way to prevent this self-pollination. Germination and growth of the pollen tube involve molecular signaling between stigma and pollen. In self-incompatibility in plants, the stigma of certain plants can molecularly recognize pollen from the same plant and prevent it from germinating. [15]
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 ...
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 ...
In plants with SI, when a pollen grain produced in a plant reaches a stigma of the same plant or another plant with a matching allele or genotype, the process of pollen germination, pollen-tube growth, ovule fertilization, or embryo development is inhibited, and consequently no seeds are produced.
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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 ...