相关概念视频
02:16Light Acquisition
In order to produce glucose, plants need to capture sufficient light energy. Many modern plants have evolved leaves specialized for light acquisition. Leaves can be only millimeters in width or tens of meters wide, depending on the environment. Due to competition for sunlight, evolution has driven the evolution of increasingly larger leaves and taller plants, to avoid shading by their neighbors with contaminant elaboration of root architecture and mechanisms to transport water and nutrients.
02:00Photoreceptors and Plant Responses to Light
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
01:27C4 Pathway and CAM
Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative pathways to fix carbon and conserve energy loss due to photorespiration. Photorespiration is the process that occurs when the oxygen concentration is high. Under such conditions, the rubisco enzyme in the Calvin cycle binds O2 instead of CO2, which halts photosynthesis and consumes energy.
C4 Pathway
The C4 pathway is used by plants such as...
C4 Pathway
The C4 pathway is used by plants such as...
02:45Biological Clocks and Seasonal Responses
The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
02:40Epiphytes, Parasites, and Carnivores
Plants often form mutualistic relationships with soil-dwelling fungi or bacteria to enhance their roots’ nutrient uptake ability. Root-colonizing fungi (e.g., mycorrhizae) increase a plant’s root surface area, which promotes nutrient absorption. While root-colonizing, nitrogen-fixing bacteria (e.g., rhizobia) convert atmospheric nitrogen (N2) into ammonia (NH3), making nitrogen available to plants for various biological functions. For example, nitrogen is essential for the biosynthesis of the...
02:12Short-distance Transport of Resources
Short-distance transport refers to transport that occurs over a distance of just 2-3 cells, crossing the plasma membrane in the process. Small uncharged molecules, such as oxygen, carbon dioxide, and water, can diffuse across the plasma membrane on their own. In contrast, ions and larger molecules require the assistance of transport proteins due to their charge or size. Transport across membranes also occurs within individual cells, playing a variety of essential roles for the plant as a whole.
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The energy balance of leaves of the evergreen desert shrub Atriplex hymenelytra.
Oecologia·2017
概括
许多植物物种表现出白天叶子运动,跟踪太阳以优化光合作用或减少水损失. 这种太阳跟踪行为在沙漠一年生植物中很常见,特别是在较短的生长季节.
科学领域:
- 植物生理学 植物生理学
- 生态生态学 生态生态学
- 光合作用 光合作用
背景情况:
- 许多植物物种表现出白天叶子运动.
- 叶子的方向垂直或平行于太阳的光线.
- 这种现象在不同家族的C(3) 和C(4) 植物中都能观察到.
研究的目的:
- 为了研究植物中日间叶子运动的现象.
- 为了了解太阳跟踪在沙漠一年生植物的生态意义.
- 为了将叶子的方向与光合作用率和水损失相关联.
主要方法:
- 关于植物叶子移动的观测研究.
- 分析叶子方位在白天发生的变化.
- 叶子位置与环境因素和生理反应的相关性.
主要成果:
- 植物中日间叶子运动或太阳跟踪非常普遍.
- 在沙漠一年生植物中,随着生长季节的缩短,太阳追踪增加.
- 垂直于太阳的叶子显示出更高的光合作用率.
- 面向与太阳平行的叶子显示温度降低和水损失.
结论:
- 日间叶子运动是优化植物在不同环境中的表现的关键适应.
- 太阳能追踪平衡了光合作用收益与水资源保护需求.
- 这种行为对于生存和繁殖至关重要,特别是在干旱的生态系统中.