Experiments on the effects of growth hormone and ethylene on leaf abscission
Experiments on the effects of growth hormone and ethylene on leaf abscission
The natural regulation of abscission is effected by the inhibitory action of growth hormone supplied from the leaf (or fruit) and the promotional action of ethylene, with young leaves producing large amounts of growth hormone, thus preventing abscission. However, when the leaf ages, on the one hand, the growth hormone supplied from the leaf drops to a low level, making the isolated cells more sensitive to ethylene; on the other hand, senescence increases ethylene biosynthesis so that abscission occurs.
Operation method
Experiments on the effects of growth hormone and ethylene on leaf abscission
Principle
The natural regulation of abscission is effected by the inhibitory action of growth hormone supplied from the leaf (or fruit) and the promotional action of ethylene, with young leaves producing large amounts of growth hormone, thus preventing abscission. However, when leaves age, on the one hand, the growth hormone supplied from the leaf declines to a low level, making the isolated cells more sensitive to ethylene; on the other hand, senescence increases ethylene biosynthesis so that abscission occurs. The present experiment was carried out with a section of explants including the petiole abscission zone. It can be observed that when a high concentration of growth hormone was applied, abscission was still delayed due to the insensitivity of the tissue to ethylene, although it caused a large amount of ethylene release. However, under conditions of low growth hormone concentration, the disarticulated tissues entered an ethylene-sensitive phase. The release of ethylene promoted by growth hormone accelerated petiole abscission.
Materials and Instruments
Soybean plants Move I. Experimental materials and methods For more product details, please visit Aladdin Scientific website.
Naphthalene acetic acid
Petri dishes, blades, tweezers, agar.
Apparatus and drugs
Petri dishes 6cm in diameter Four for each group, one petri dish 3cm in diameter
Razor blades 2 per group
Tweezers 2 per group
Agar
Naphthalene acetic acid
10-15 day old soybean plants
II. Experimental steps
1. Prepare four petri dishes with a diameter of 6 cm, number them and pour the following ingredients into them:
(1) 1.5% agar about 10 ml
(2) 10 ml of 1.5% agar containing 5 × 10-5 M naphthalene acetic acid
(3) 10 ml of 1.5% agar containing 5 x 10-4 M naphthalene acetic acid
(4) Place a 3-cm Petri dish into a 6-cm Petri dish. Pour 5 ml of 1.5% agar containing 5 x 10-4 M naphthalene acetic acid into the 6-cm dish and 5 ml of 1.5% agar without any growth factor into the 3-cm dish.
(5) Cover the petri dish with a lid and allow it to cool and solidify at room temperature.
2. Cut off the fully expanded leaves from soybean plants grown for 10-15 days at 25℃ in the greenhouse, leaving 0.5cm long petiole and midvein, remove the leaf flesh tissue cleanly, and put the cut explants on wet filter paper first, and cut a total of 50 uniformly sized explants in each group.
3. Insert the base of every 10 such explants into 1.5% agar about 1-3 M M deep in each petri dish. After insertion, cover the petri dishes with the fourth treatment above with a tight seal of adhesive tape.
4. place the petri dishes at 25°C under light conditions.
III. Observation records and calculation of results
After two days and one week, the number of explants that underwent abscission was recorded for each treatment by gently touching the explants with a pencil.
The results of each group were written on the blackboard, the mean was calculated and the significance of difference was determined for each treatment.