Temperature and Humidity Recorder Measure Soil Temperature and Net Photosynthetic Rate

Different temperatures and humidity will have different effects on plant growth and photosynthesis. At different temperatures, the transpiration and photosynthetic rate of the plant will change as the soil temperature changes, and the intercellular CO2 concentration will also have They fluctuate; the correlations between them are also different, and there are differences in the changes and principles of the various physiological mechanisms of plants under different temperature and humidity conditions measured by a temperature and humidity recorder.

The experiment mainly focused on the Primula sinensis growing in the high mountains. The temperature and humidity recorders analyzed the response of the net photosynthetic rate and transpiration rate to the temperature change under different soil temperatures, and the response of the net photosynthetic rate and transpiration rate to the soil temperature under different temperature conditions. . To reveal the suitable soil temperature and temperature range for photosynthetic growth of alpine plants, and to explore the synergy or stress between soil temperature and air temperature effects on photosynthesis and transpiration.

A heat sink is made of a 5 cm thick foam plastic box. The top cover has a round hole to hold the flower pot. Use a water pump to make the water flow and keep the water temperature even. A soil thermometer was inserted near the center of the pot and the soil depth was 5 cm. The temperature and humidity recorder was used to monitor the soil temperature. At 18:00 on the day before the test, the insulated water tank and 3 pots of Primrose Springs were placed in an intelligent artificial climate chamber. The air humidity in the chamber was 80%, and the temperature was adjusted to the soil temperature of the next day's test. The dark culture was conducted for 12 hours. After the experiment, the flowerpots were placed in the artificial climate box for 3~5h. The temperature of the flowerpot soil was consistent with the temperature in the climate chamber.

In the above, through temperature and humidity recorder measurement and research under different conditions, we can see: when the soil temperature is 10°C and 15°C, the maximum temperature of the net photosynthetic rate of leaves is 20°C. When the soil temperature was between 20°C and 25°C, the maximum temperature of the leaf's net photosynthetic rate was 25°C. When the ambient temperature is constant but the soil temperature is changed, the photosynthetic rate of plants will change greatly. . In addition, when the soil temperature changes, the optimum temperature for photosynthesis of the leaves will also change.