The cultivated grapevine is 99% monoecious (monoecious) with hermaphrodite, i.e. bisexual, flowers. It is 98% self-fertilising, but can also be cross-fertilised. Wild vines are mostly dioecious (dioecious), i.e. there are plants with exclusively male or exclusively female flowers, so that a so-called self-pollination (self-fertilisation) is excluded. In monoecious plants, both sexes occur on one plant.
The flowers can be separate-sexed, so that male and female flowers occur on the same plant but in separate inflorescences, or they are hermaphroditic h ermaphrodite flowers, in which male and female sexual organs are united in one flower. The vine is an angiospermous plant. This means that the flower bud is covered with the perianth, which is opened or shed during flowering to enable pollination (and subsequent fertilisation). As a rule, the cultivated grape varieties are bisexual. However, there are also unisexual (female) varieties with exclusively female flower organs.
The picture on the left shows a closed vine flower, the picture in the centre shows the shedding of the caps before pollination and the picture on the right shows the flower bud in full bloom shortly before pollination or fertilisation. 1 = five-lobed corolla (cap), 2 = stigma, 3 = anther, 4 = stamen, 5 = pistil, 6 = ovary, 7 = nectaries (honey glands), 8 = calyx.
Sexual organs of a flowering plant
There are three ways in which the sexual organs of plants are arranged. In the first possibility, the "sexual parts" are separate on two different plants, for example one tree with only functional male parts (and stunted female parts), and a second tree with only functional female parts (and stunted male parts). Now the two have to "come together". The plants are dependent on external help, i.e. wind or insects. Many flowers are therefore not fertilised and the fruit yield can be relatively low. Such plants are called "dioecious" because the male and female sexual organs are each located in their own "house" (plant), so to speak. This...
