What is a grape variety?
What is a grape variety?
The reproductive organs of the grape are contained in the flowers. The grape has evolved as a wind-pollinated, animal-dispersed species. So, while the flowers are small and insignificant, the fruit is brightly coloured, sweet and attractive. The flowers of nearly all commercial grape varieties are hermaphrodite, that is , thery contain both male and female organs within the same flower. Sexual reproduction commences when the anthers (equivalent to testes) mature and release pollen (equivalent to spermatozoa). The pollen is transported by wind, and lands on the stigmas of other grape flowers. This is the process of pollination. The pollen transfer its genetic material via a tube to the ovary, where it combines with the genetic material contained in the ovules (eggs), in the process of fertilization. The fertilized ovules will develop into seeds, and the ovary develops into the surrounding flesh and skin of the grape. Just as with human reproduction, the seed will have a selection of genetic material from both parents. Also, as with humans, the expressed characteristics of the resulting “offspring” are not simply a combination of the expressed characteristics of the parents. They may favour one parent over the other, and the offspring will exhibit some characteristics that are to be found in neither parent. The expressed characteristics that interest the wine producer are aspects such as yields, hardiness, disease-resistance, fruit character and levels of tannin, acidity and sugars within the grape. Sexual reproduction results in the natural evolution of species and creates the possibility of adaptation through natural selection.
The reproductive organs of the grape are contained in the flowers. The grape has evolved as a wind-pollinated, animal-dispersed species. So, while the flowers are small and insignificant, the fruit is brightly coloured, sweet and attractive. The flowers of nearly all commercial grape varieties are hermaphrodite, that is , thery contain both male and female organs within the same flower. Sexual reproduction commences when the anthers (equivalent to testes) mature and release pollen (equivalent to spermatozoa). The pollen is transported by wind, and lands on the stigmas of other grape flowers. This is the process of pollination. The pollen transfer its genetic material via a tube to the ovary, where it combines with the genetic material contained in the ovules (eggs), in the process of fertilization. The fertilized ovules will develop into seeds, and the ovary develops into the surrounding flesh and skin of the grape. Just as with human reproduction, the seed will have a selection of genetic material from both parents. Also, as with humans, the expressed characteristics of the resulting “offspring” are not simply a combination of the expressed characteristics of the parents. They may favour one parent over the other, and the offspring will exhibit some characteristics that are to be found in neither parent. The expressed characteristics that interest the wine producer are aspects such as yields, hardiness, disease-resistance, fruit character and levels of tannin, acidity and sugars within the grape. Sexual reproduction results in the natural evolution of species and creates the possibility of adaptation through natural selection.
还没人赞这篇日记
