Dust Pollution: Harming Our Green Friends

Dust pollution is a pressing issue that poses a serious threat to the ecosystem. It is mainly caused by industrial processes, such as coal mining, quarrying, and cement production, and can have detrimental effects on plants. When dust particles come into contact with plants, they can adhere to the leaves, affecting their physiological processes and morphology.

Dust deposition on leaves can interfere with photosynthesis by reducing the rate of carbon dioxide exchange, carbon assimilation, transpiration, and net photosynthesis. It can also lead to stomatal closures, increased leaf temperature, and degradation of chlorophyll, resulting in poor vegetation health and reduced productivity.

Additionally, dust particles may enter the substomatal cavity and come into contact with the spongy mesophyll cells, disrupting the photosynthetic reaction center and impeding overall plant growth. The chemical composition of dust, including toxic substances, can induce mechanical injuries, produce necrotic spots, and cause physiological changes in plants, such as gaseous exchange imbalance, deformed tissues, and reduced carbon assimilation.

The impact of dust pollution varies depending on the plant species and the characteristics of dust particles, with smaller particles generally causing more damage. Understanding the effects of dust pollution on plants is crucial for developing effective strategies to mitigate its negative consequences and ensure the health and productivity of vegetation.

Dust can cause leaf chlorosis by interfering with chlorophyll biosynthesis

Dust pollution can interfere with chlorophyll biosynthesis in plants in several ways.

Dust particles can clog stomata openings, reducing the rate of carbon dioxide exchange, carbon assimilation, transpiration, and net photosynthesis. This can lead to a reduction in the photosynthetic rate and quantum yield, and an increase in leaf temperature.

Dust particles can also cause an increase in the leaf temperature, which can lead to the denaturation of photosynthetic enzymes and a decrease in leaf photosynthesis.

Additionally, dust particles can interfere with the chemical reactions of chlorophyll biosynthesis by altering the pH of the cell sap, leading to chlorophyll degradation and reduced photosynthetic activity.

The effects of dust on chlorophyll biosynthesis can vary depending on the size and chemical composition of the dust particles, the plant species, and the duration of exposure.

Dust can block stomata, reducing the plant's ability to photosynthesise

Dust particles can enter plants through their stomata, which are small openings on the leaves that allow the intake of carbon dioxide and the expulsion of oxygen. When dust blocks the stomata, gaseous diffusion is hampered, and the plant is unable to receive sufficient carbon dioxide for photosynthesis. This leads to a decrease in the rate of photosynthesis as carbon dioxide is one of the substrates of the process. Additionally, the increased concentration of oxygen inside the plant due to the blocked stomata can lead to photorespiration, further reducing the rate of photosynthesis.

The effects of dust on plants vary depending on the species and the size of the deposited particles. Fine dust particles can clog the stomata, reducing photosynthesis, increasing leaf temperature, and enhancing transpiration. Deposition of dust on leaves can also alter their optical properties, particularly in the visible and near-infrared range of the wavelength. This can lead to an increase in leaf temperature and changes in grazing patterns for animals.

The impact of dust on plants is not limited to physical effects. Chemical and biochemical changes can also occur. For example, alkaline dust deposited on leaf surfaces can result in leaf chlorosis and death of leaf tissue. Additionally, dust deposition can lead to stomatal clogging, reducing the rate of carbon dioxide exchange, carbon assimilation, transpiration, and net photosynthesis.

The presence of dust on leaves can also affect the pigments in the plant. Chlorophyll, which is essential for photosynthesis, can be reduced due to dust deposition. This reduction may be caused by the shading effect of dust particles on the leaf surface, interfering with the gaseous exchange and increasing leaf temperature.

Overall, dust deposition on plants, especially the blockage of stomata by dust particles, can have significant negative consequences on the plant's ability to photosynthesize, leading to reduced growth and development.

Dust can cause physical injury to leaves

The size of dust particles also matters. Fine dust particles can cause effects at very low concentrations, whereas coarse particles require higher doses to have an impact. The chemical nature of dust particles is also a factor, as certain soluble toxicants in dust can cause necrotic spotting on leaves.

Dust deposition on leaves can also lead to the formation of a hard, adherent crust in the presence of moisture. This crust can damage plant tissue and inhibit growth by screening light and plugging stomata openings, which are essential for gas exchange and photosynthesis.

Leaves with wet dust deposits may also experience an increase in leaf temperature, making plants more susceptible to water stress and other negative effects of drought. Furthermore, dust deposition can cause physical injury to the cuticular and epidermal traits of leaves, affecting their adhesiveness for particulates.

Overall, dust can have detrimental physical effects on leaves, impacting their structure and functionality and ultimately leading to reduced growth and development.

Dust can increase leaf surface temperature

The increase in leaf surface temperature is due to the deposition of dust particles on the leaves, which can be influenced by factors such as light exposure, the leaf's ability to reflect light, air circulation, humidity, and the plant's water use efficiency.

The increase in leaf surface temperature can have the following effects:

• Stress response: High leaf surface temperature can lead to heat stress, causing plants to activate protective measures that divert energy from growth.
• Transpiration increase: Plants may increase transpiration to cool down, leading to faster water loss.
• Photosynthesis inhibition: Excessive heat can damage the plant's photosynthetic machinery, reducing its ability to produce energy for growth.
• Reduced nutrient uptake: High leaf surface temperature can disrupt the balance of nutrient uptake, leading to deficiencies or toxicities.

The consequences of these responses can include reduced potency, impaired terpene profile, decreased yield, poor bud structure, and reduced trichome production, all of which can negatively affect the quality and quantity of the final product.

Therefore, understanding and managing leaf surface temperature is crucial for optimising plant health and productivity.

Dust can reduce fruit setting and inhibit pollen germination

Dust pollution can have a detrimental impact on plants, affecting their growth, reproduction, and overall health. One of the ways dust achieves this is by reducing fruit setting and inhibiting pollen germination.

Firstly, dust deposition on leaves can lead to a decrease in the synthesis of chlorophyll, the pigment responsible for absorbing light energy for photosynthesis. This reduction in chlorophyll is caused by the shedding effects of dust on leaf surfaces, as well as the alkaline conditions created by the solubility of dust particulates in cell sap. The formation of a hard crust on leaves due to dust can further inhibit leaf growth and function.

Additionally, dust deposition can result in stomatal clogging, which negatively impacts the rate of carbon dioxide exchange, carbon assimilation, transpiration, and net photosynthesis. This is because dust particles can physically block the stomata, tiny pores on the surface of leaves that facilitate gas exchange. With reduced photosynthesis and carbon assimilation, plants have fewer resources to dedicate to fruit production, leading to reduced fruit setting.

Moreover, dust deposition can alter the acidity of the stigma, turning the usually acidic secretion into an alkaline condition. This change in pH creates an unfavourable environment for pollen germination, which is necessary for successful fertilisation and yield.

The impact of dust on fruit setting and pollen germination is further exacerbated by the abrasive effects of dust, particularly under high wind speeds. The protective leaf cuticle can be physically removed by abrasive dust, leaving the plant more susceptible to diseases and pests.

Overall, dust pollution can significantly hinder the reproductive processes of plants by reducing fruit setting and inhibiting pollen germination through a combination of physiological, biochemical, and physical mechanisms.

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