According to the similarity of the structure and physiological function of the two sides of the leaf midvein, you can first cut off half of the leaf in the dark, the remaining half of the leaf to be carried out for a certain period of time after photosynthesis, there is an accumulation of dry matter, in the case of isolation of photosynthesis products transported outward (i.e., to kill the phloem without damaging xylem so that the supply of water, etc., to carry out normal), and then determine the dry weight of half of the leaf, and the difference is the accumulation of the photosynthesis products of the leaf to be measured in that time. Amount
Operation method
Experiments on the determination of photosynthetic intensity of plants
Principle
According to the similarity of the structure and physiological function of the two sides of the leaf midvein, you can first cut off half of the leaf in the dark, the remaining half of the leaf to be photosynthesis for a certain period of time, there is an accumulation of dry matter, in the case of isolation of photosynthesis products transported outward (i.e., to kill the phloem without damaging xylem so that the supply of water, etc., to carry out normally), and then determine the dry weight of the half of the leaf, and the difference is the accumulation of photosynthesis products of the measured leaf in that time. The difference between the two is the accumulation of photosynthesis products in the measured leaf at that time.
Materials and Instruments
Cotton Soybean Move 1. Selection: in the field to select the growth of more consistent cotton plants, in each plant on the selection of parts of symmetry is good, thick and thin uniformity of the function of the leaf without pests and diseases, in turn, the number of hanging. Common Problems Given that a leaf taken in the dark in the morning weighs a mg and undergoes photosynthesis for b mg, the sampling area is A cm 2 and the illumination time is t, the total photosynthetic rate is For more product details, please visit Aladdin Scientific website.
Trichloroacetic acid.
Scissors, punch, beaker, balance, absorbent cotton, cardboard, glass rod, weighing flask.
2. Treatment: in the selected leaf base for treatment to destroy the phloem and retain the xylem, so that the leaves rely on the xylem to get enough water, while photosynthetic products and transport out.
(1) ring peeling method: with a razor blade to the petiole of the outer skin ring peeling about half a centimeter (suitable for the bast thicker and easy to peel off the plant).
(2) Inhibition method: Use a cotton ball soaked with 5% trichloroacetic acid to apply a ring at the base of the petiole.
(3) Scald method: Use a cotton ball dipped in boiling water above 90℃, then scald the base of the petiole for one minute, if there is obvious water-soaked indicates complete scald. For the bast thinner, xylem not hard plants with scald method is good. However, the degree of scald is not easy to grasp, so treatment with the protein precipitant trichloroacetic acid is preferred. In order not to change the angle of the leaves can also be surrounded by tinfoil or plastic tubes.
3. Cutting samples: leaf base treatment is completed, you can cut the sample, record time, in order to cut half of the leaf (the main vein is not cut), according to the number of the order of the clip in the moist gauze, stored in a dark place. After four or five hours, and then cut off the other half of the leaf in turn, also according to the number of the clip in the moist gauze, the order of the two leaf cuts are consistent, so that the leaves experience an equal number of hours of light.
4. Weighing comparison: the two halves of the same leaf blade corresponding parts of the iterative together, in the absence of thick veins into a known area of the template, with a razor blade along the edge of the two leaf pieces, respectively, in the light and dark in the two weighing bottles, or with a perforated device (known diameter), in the leaf blade drilling 20-40 pieces of the garden slice (try to minimize the leaf with the veins), respectively, in the light and the dark in the two weighing Boxes were baked at 105°C for 10 minutes to kill the cells, then lowered to 70-80°C for 3-4 hours until constant weight. The aluminum boxes were taken out and cooled in a desiccator before being weighed. (Accurate to 1mg). 