Temperature and humidity illuminance in plant growth status and related analytical instruments

From the perspective of agricultural practice, plant growth plays an absolute role in agricultural production. Plant growth is good, crop yields are high, and farmers' income is high. The people’s income level is high, and the entire country’s economy will go up. Plant growth includes these aspects: the development of special organs, the development of whole plants, etc. At present, scientists have identified 52 factors that affect plant growth. Such as soil organic matter, soil moisture, root depth, temperature, humidity, light intensity, wind speed and so on. Here we focus on the analysis of the effects of temperature and humidity on the plant.

Effect of temperature on plant growth

Plants can grow only within a certain temperature range. The effect of temperature on growth is comprehensive. It can affect the growth of plants by affecting metabolic processes such as photosynthesis, respiration, and transpiration, as well as affecting the growth of plants by affecting the synthesis and transportation of organic matter, as well as directly affecting soil temperature and temperature. Affect the growth of plants by affecting the absorption and transport of water and fertilizers. Since the activities of enzymes involved in metabolic activities have different manifestations at different temperatures, the effect of temperature on plant growth also has the lowest, most suitable, and highest temperature three-basis points. Plants can only grow at the lowest temperature and highest temperature range. Although the optimum temperature for growth refers to the fastest growing temperature, this is not the most robust temperature for plant growth. Because at the optimum temperature, the organic matter in the plant is consumed too much and the plant grows slender and weak. Therefore, cultivating robust plants in production practice often requires temperatures below the optimal temperature, which is called the optimal temperature for coordination.
Different plants grow at different temperature points. This is related to the climatic conditions of the origin of the plant. For tropical or subtropical plants, the three-point temperature is higher at 10°C, 30-35°C, and 45°C. In plants with temperate zones, the three-point temperature is lower, which is 5°C, 25-30°C, 35 respectively. ~40°C; plants in the native cold zone have a lower three-point temperature, and plants in the Arctic or high mountains can grow at temperatures below 0°C or 0°C, and the optimum temperature rarely exceeds 10°C.
The three-point temperature of the same plant also varies with the organ and growth period. In general, the temperature of root growth is lower than that of buds. For example, the minimum temperature for apple root growth is 10°C, the optimum temperature is 13-26°C, and the maximum temperature is 28°C. The aboveground parts are all above this temperature. In the different growth stages of cotton growth, the optimum temperature is also not the same. The optimum temperature for the elongation of primary and hypocotyls was 33°C when the seeds were germinated, but the roots decreased to 27°C after several days, while the hypocotyl elongation The rise is 36°C. In most annual plants, from the initial stages of growth from flowering to fruiting, the optimal temperature for growth is gradually increasing, and this requirement is just the same as the temperature change from spring to early autumn. Seeding too late will make the seedlings prosperous and weak, and if the summer temperature is not high enough, it will affect growth and delay maturity.

The experimental data of the artificial climate room prove that the plant's vegetative growth is best during the daytime when the temperature is high and the night temperature is low. For example, a tomato plant grows at a temperature of 26°C and a nighttime temperature of 20°C at a high temperature of night and night, and grows at a temperature of 25°C at a constant temperature. Under natural conditions, it also has periodic changes with higher daily temperatures and lower night temperatures. The response of plants to this cyclical change in day and night temperatures is called the warm cycle phenomenon of growth.
The reason that the lower day temperature is higher and the lower the night temperature can promote the vegetative growth of plants, the higher the daytime temperature is, and the higher the photosynthetic rate is in the strong light, which provides sufficient material for growth; the lower the night temperature, the less the respiration can be. Consumption of organic matter. In addition, the lower night temperature favors the growth of roots and the synthesis of cytokinins, thus also increasing the growth rate of the whole plant. In the greenhouse or greenhouse cultivation, we must pay attention to changing the temperature of day and night, so that under natural conditions, the effects of water, mineral, light, temperature and other factors on plant growth are cross-cutting and comprehensive. First of all, there are mutual influence between environmental factors. For example, rainy days, dim lighting, falling temperatures, increased soil moisture, poor soil ventilation, and other reactions can occur in chains, affecting plant growth. Secondly, environmental factors affect the plant body and are closely related to life activities. They also affect each other. For example, light promotes photosynthesis, photosynthetic activity affects transpiration, and transpiration affects water supply. They have mutual promotion and mutual restraint. In agricultural production, we must pay attention to the special effects of various environmental conditions on the individual physiological activities of growth. We must also apply the viewpoint of dividing into two parts, grasp the main contradictions, and adopt reasonable measures to properly promote and inhibit the growth of plants. To achieve the purpose of cultivation.

The effect of humidity on plant growth

There are many factors affecting absolute humidity, which mainly depend on the source of moisture, the ability to transport water and the ability of air to maintain moisture. Therefore, the factors that affect water vapor supply such as precipitation, the presence of water bodies, the level of soil moisture, and the evaporation conditions affect the conditions of water vapor transport such as wind, vertical air flow, and conditions that affect the ability of air to maintain water vapor, such as temperature, may affect Absolute humidity. Generally, the tropical ocean air mass is higher than the polar ocean air mass; at the same latitude, the areas affected by the marine air mass have higher humidity than those controlled by the continental air mass. Absolute humidity in a year is higher during the rainy season than during the dry season. The change of absolute humidity in the day is the largest in the coastal areas and the fall and winter seasons, the smallest in the early morning and the single-peak changes in the morning; in other areas, it is mostly bimodal, with the two high points appearing at 9 to 10 o'clock respectively. Before and after, two low points appeared before and after sunrise. The vertical distribution of absolute air humidity decreases with height.
Relative humidity is determined by absolute humidity on the one hand and air temperature on the other. In cold regions and seasons, the air humidity is easily saturated, and in the case of absolute humidity or vapor pressure is not too high, the relative humidity may be higher. Under the same absolute humidity conditions, the relative humidity in warm areas and seasons tends to be low. The general trend of the annual average relative humidity distribution in mainland China is decreasing from southeast to northwest, and the mountains are higher than the plains. The annual change of relative humidity is generally higher in winter than in summer in the inland dry areas; the lowest in spring in North China and northeast and higher in winter than in winter;
Relative humidity or saturation of air is one of the important factors affecting water absorption and transpiration of plants. When the relative humidity is small (the saturation difference is large), if the soil moisture is sufficient, the plant transpiration is more vigorous and the plant growth is better. If the air humidity is under saturation conditions for a long time, the growth of plants will be inhibited, which will result in the decrease of the grain filling rate of grains, the aggravation of the cotton bud bells, the decrease of cotton vitality and the quality of cotton harvest. Relative humidity is too small, it will increase the soil drought or cause atmospheric drought, especially in the conditions of high temperatures and lack of soil moisture, the water balance of the plant is destroyed, water does not make ends meet, will hinder growth and cause reduced production. The relative humidity and the saturation difference can restrict the time of anther cracking, pollen scattering and germination in some plants, thus affecting the pollination and fertilization of plants. Humidity is also closely related to the occurrence of crop pests and diseases. In the environment where the wheat midge sucks moisture, cotton aphid and red spider are suitable for living in a relatively low humidity environment. Humidity can easily lead to a variety of diseases such as wheat rust. For livestock, the general relative humidity of 50 ~ 70% is appropriate, the humidity is too low, easy to cause mucous membranes, skin, leg nails dry and cause bacteria and other infections, humidity is too high, easy to cause bacteria and parasites to breed. The combination of high humidity and high temperature can inhibit evaporation and heat dissipation of the carcass, and can easily cause accumulation of heat in the livestock. The combination of high humidity and low temperature increases the thermal conductivity of the air, and it easily aggravates the disease caused by animal heat loss.

Effect of light intensity on plant growth

Effect of Illuminance on Growth and Development of Medicinal Plants

Light is the source of energy for plants to carry out photosynthesis. Photosynthesis mainly depends on the organ's chlorophyll organ. In plant ecology, it is generally divided into three categories: positive plants, negative plants, and shade-tolerant plants according to their different requirements for light:

Positive plants are plants that grow robustly in strong light conditions and grow poorly under covert and low light conditions. Such as licorice, Atractylodes, peony, rehmannia, cassia, mint and so on.

Negative plants are plants that grow well under weaker light conditions than under strong light conditions. However, this does not mean that the weaker the light requirements of the negative plants are, the better, because when the light is too weak to reach the compensation point of the negative plants, it cannot grow normally, so the negative plants require weaker light. It is also only relative to positive plants. Negative plants grow more in moist, shady areas or in the jungle, such as Liancao, ginseng, Arisaema, and Coptis.

A shade-tolerant plant refers to a plant that falls between two categories. This type of plant grows best under full sun, but it can tolerate moderate concealment, or it requires lighter shading during childbirth. Such as when the reference, Huang Jing, cinnamon, butternut and so on.

However, the same plant in different development stages of the light requirements are not the same. Such as woody plants such as Magnolia, Eucommia and so on, the seedling period needs to be shaded and it is afraid of glare. When the ginseng seedlings are pleasing to the shade, the adult plants are hi yang Although Rhizoma Coptidis is a negative plant, its growth tolerance is different at different stages of growth. The seedling stage is the most shade-tolerant, but in the fourth year after planting, the shade can be removed and grown under strong light, which is conducive to root growth. Under normal circumstances, plants need more nutrients and require higher light in flowering and solid stages or in the formation of tuber and other storage organs. Understanding the ecological types of light intensity of plants is very important in the rational cultivation of medicinal plants, interplanting, and domestication.

Since it is understood that the temperature, humidity, and illumination have a great influence on the plants, it is necessary to grasp the temperature, humidity, and illuminance of plant growth. At present, there are already manufacturers on the market that can measure a parameter or a variety of parameters. Such as temperature and humidity recorder is to measure the temperature and humidity of two parameters; there are three parameters, such as temperature and humidity three-parameter recorder. Of course, there are also instruments that can only measure a single parameter, such as a temperature recorder, which can only measure the temperature of the environment. Therefore, if you want to understand the growth of plants, it is necessary to have a temperature and humidity photometer, and this instrument can measure a variety of parameters, so that you get environmental data in practical applications quickly and easily.