The developmental process of plant flower buds is often influenced by environmental factors . In particular, temperature and photoperiod are affected. The study of the external conditions required for the differentiation of plant flower buds is very important for the study of the mechanism of flower bud differentiation and the regulation of plant development.
Principle
(1) The phenomenon of plant vernalization: In the process of growth and development of winter crops (such as winter wheat), it is necessary to go through a period of low temperature before the growth cone can begin to differentiate, which is called the phenomenon of plant vernalization. It can be used to check the differentiation of growth cones as well as the observation of plant nodulation and tasseling to determine whether the plant has passed through vernalization, which has certain application value in production and scientific research.
(2) Plant photoperiodic phenomenon: many plants need to undergo a certain day and night alternation of light and dark to flower, known as photoperiodic phenomenon. It is known that the length of the dark period is the key to determining whether or not a flower can bloom, and the leaf is the organ that feels the effect of photoperiod. Under certain photoperiodic conditions, certain special metabolites are formed in the leaf, which are transferred to the growing point and lead to the formation of flower buds. In this experiment, short-day plants were treated with short days, intermittent days and intermittent nights under natural light conditions, in order to understand the effects of day and night light and darkness alternation and the length of light on the flowering and fruiting of short-day plants.
Operation method
Observations on plant vernalization and photoperiodic phenomena
Principle
(1) The phenomenon of plant vernalization: In the process of growth and development of winter crops (such as winter wheat), it is necessary to go through a period of low temperature before the growth cone can begin to differentiate, which is called the phenomenon of plant vernalization. It can be used to check the differentiation of growth cones as well as the observation of plant nodulation and tasseling to determine whether the plant has passed through vernalization, which has certain application value in production and scientific research. (2) Plant photoperiodic phenomenon: many plants need to undergo a certain day and night alternation of light and dark to flower, known as photoperiodic phenomenon. It is known that the length of the dark period is the key to determining whether or not a flower can bloom, and the leaf is the organ that feels the effect of photoperiod. Under certain photoperiodic conditions, certain special metabolites are formed in the leaf, which are transferred to the growing point and lead to the formation of flower buds. In this experiment, we used short-day plants as materials, and gave them short days, intermittent days, intermittent nights and other treatments under natural light conditions, in order to understand the effects of alternation of light and darkness during the day and night, and the length of light on the flowering and fruiting of short-day plants.
Materials and Instruments
Materials: seeds of long day plants such as winter wheat, short day plants such as soybean, rice, chrysanthemum, and aleurone. Move The basic process of observation of plant vernalization and photoperiodic phenomena can be divided into the following steps: (i) Observation of plant vernalization phenomenon 1. select a certain number of winter wheat seeds (preferably with strong wintering varieties), respectively, 50 d, 40 d, 30 d, 20 d and 10 d before sowing to absorb water and sprouting, placed in a petri dish, and put in a refrigerator at 0-5 °C for vernalization. 2. in the spring (about late March or early April), take out the seeds from the refrigerator and put them in the refrigerator for the vernalization process. 2. Wheat seeds treated for different days and seeds not treated with low temperature but allowed to germinate were taken from the refrigerator in the spring (around late March or early April) and sown simultaneously in pots or experimental plots. 3. During the growth period of wheat seedlings, each treatment was subjected to the same fertilizer and water management, and plant growth was observed at all times. When the wheat seedling with the highest number of days of vernalization treatment appears to pull out the nodes, take one wheat seedling in each treatment, peel out the growth cone with a dissecting needle, and cut it off, put it on a slide, add 1 drop of water, observe it under a dissecting microscope, and make a sketch. Compare the differences between the growth cones of the different treatments. Continue to observe plant growth until the wheat plant with the most days of treatment flowers. Record the observations in Table 34-1. (ii) Observations of plant photoperiodic phenomena Soybean, rice, chrysanthemum, auricularia and other short-day plant cultivation in the long day conditions (sunshine hours per day in 18 h or more), when the soybean seedlings grow the first compound leaves, or auricularia, rice seedlings grow 5 ~ 6 leaves (night temperature at 18 ~ 20 ° C or more), that is, according to the method of Table 34-2 to give the different treatments, in general, continuous treatment can be completed in 10 d, auricularia only 1 ~ 2 d can be. Caveat 1. note varietal differences in experimental materials and geographical differences in varieties. 2. Note the geographical differences in winter wheat varieties. For more product details, please visit Aladdin Scientific website.
Equipments: refrigerator, dissecting mirror, shackle, dissecting needle, slide, petri dish, black cover (white outside) or dark box, dark cabinet or dark room; 6~100 W fluorescent lamps or red light bulbs, automatic control device for light source timer switch and so on.
