4271895
Beschreibung
Karteikarten von Jasmine Wells, aktualisiert more than 1 year ago
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Erstellt von Jasmine Wells
vor fast 9 Jahre
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| Frage | Antworten |
| What is the vegetative stage of a plant? | The phase when a seed germinate and a young plant is formed that grows roots, stems and leaves. |
| When does the vegetative stage end? | When the meristems in the shoot start to produce parts of flowers instead of leaves. I.e. Reproductive stage. |
| Why are flowers useful? | Flowers are structures that allow for sexual reproduction - thereby to increase variety. |
| What factor(s) play a role in transforming leave producing shoot to a flower producing shoot? | -Temperature - Dark period (main trigger). |
| What are short day plants? | Are plants that flowers when the days are short and the nights are long. (Longer than critical day length). E.g. Chrysanthemums during autumn |
| What are long day plants? | Plants that flowers when days are long and the nights are short. E.g. Irises during the summer. |
| How can growers force flowering? | By manipulating the length of day/night to force flowering to occur. |
| How to force flowering for long day plants during the winter/autumn? | By providing additional light in the middle of the night may lead to flowering. |
| How to induce flowering for short day plants during summer/spring? | Blinds can be closed to extend nights artificially. |
| What are the 2 kinds of pigments found in leaves that is used to measure the length of dark periods? | - Phytochrome red - Phytochrome far-red. |
| What happens to phytochrome red in normal sunlight? | When Pr absorbs red light of wavelength 660nm, it is converted into phytochrome far-red |
| What happens to phytochrome far red in darkness? | When pFR absorbs far-red light, (730nm), it converts it back into pR. |
| Which of the 2 phytochromes are more stable? | pR is more stable than pFR. |
| Which of the 2 phytochromes is the more 'active' one? | pFR is the active form of phytochrome, and receptor proteins are present in cytoplasm to which pFR binds. |
| In long day plants, which of the 2 phytochromes cause gene expression? | pFR. |
| In short day plants, which of the 2 phytochrome causes gene expression? | pR. |
| What does successful reproduction of plants depend on? | Transfer of pollen from anthers on one plant to a stigma of another, of the same species. |
| What are the three most common animal pollinators? | - birds - bats - bees |
| Describe the mutualism between pollinators and flowers. | Mutualism of pollinators and flowers involve close association of the 2 organisms where both organisms benefit from the relationship. E.g. Pollinators benefit by gaining food in the form of nectar, and on the other hand, plants gains a means to transfer pollen to another plant. |
| Why should we strive to protect entire ecosystems rather than individual species? | Because more than 85% of the worlds 250,000 species of flowering plants depend on insects or other animal pollinators for survival. |
| What is pollination? | Pollination is the transfer of pollen from one anther to a stigma. |
| Define fertilisation. | The fusion of the male gamete (pollen) with the female gamete (ovule), to form a zygote. |
| leWhat happens after pollen is transferred to a stigma? | A pollen tube containing male gametes grow down the style to the ovary and then to ovule, where the gametes fertilise. |
| What is seed dispersal? | The spreading of seeds away from the parent plant. |
| Why are seeds dispersed? | this allows the seed to germinate and grow without competing with parent for nutrients, water, and sunlight and also to spread the species. |
| What does the fertilised ovule and ovary turn into? | The fertilised ovule turns into a seed and the ovary develops into a fruit. |
| What is a seed? | It is an embryo plant and food reserve. |
| What does the embryo plant consist of? | - Embryo shoot - Embryo root - One or two cotyledons. (leaves containing food reserve) |
| 1) Radicle (Embryo root) 2) Micropyle 3) Plumule (Embryo shoot) 4) Seed coat (testa) 5) Cotyledon. | |
| What are the three factors needed for successful germination? | - Water (to hydrate seed) - Oxygen ( cell respiration) - Warmth (Enzyme activity) |
| What are the functions of anthers? | Produce pollen and contain pollen sacs containing male gametes. |
| What is the function of the nectary? | Attracts insects. |
| What are the functions of the petals? | Brightly coloured to attract pollinators. |
| What is the function of the sepal? | Protects the flower bud. |
| What is the function of the filament? | The filament holds the anthers upright so that insects are likely to pass by. |
| What is the function of stigma? | Sticky so that pollen can stick to it - so that pollen grain is able to grow a tube down the style. |
| What is the job of the style? | Separates the ovary from the stigma. |
| What is the function of the ovary? | Contains the female gametes. After fertilisation occurs, the ovary develops into a fruit. |
| What is the function of the ovules? | They are the female gametes which fertilise with pollen to produce a seed. |
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