Question

Листья каштана и клена днём упругие и располагаются перпендикулярно солнечным лучам (или близко к этому положению). Вечером листья повисают. Объясните это явление пожалуйста!

Answer 1

Если так подумать то они повисают потому что они питаются солнечной энергией это им помогает окрепнуть и распологаться перпекундикулярно солнечным лучам

Answer 2

Why do the leaves of chestnut and maple trees stand upright during the day and hang down in the evening?

The phenomenon you described, where the leaves of chestnut and maple trees stand upright during the day and hang down in the evening, is known as nyctinasty. Nyctinasty is a natural response of certain plants to changes in light and temperature. It is a rhythmic movement of plant parts, such as leaves or flowers, that occurs in response to the daily light-dark cycle.

During the day, when the sun is shining, the leaves of chestnut and maple trees stand upright or spread out horizontally. This position allows the leaves to maximize their exposure to sunlight and capture as much light energy as possible for photosynthesis, the process by which plants convert sunlight into energy.

In the evening, as the sun sets and light levels decrease, the leaves of these trees undergo a change in position and start to hang down. This downward movement is believed to be a protective mechanism to reduce water loss through transpiration during the cooler and darker nighttime hours. By hanging down, the leaves can minimize their exposure to the surrounding air and reduce the surface area available for transpiration.

The exact mechanism behind nyctinasty is not fully understood, but it is thought to be controlled by changes in turgor pressure within the cells of the leaf petioles (stalks that connect the leaves to the stem). When the turgor pressure decreases, the leaf petioles become flaccid, causing the leaves to droop. Conversely, when the turgor pressure increases, the leaf petioles become turgid, causing the leaves to stand upright.

It's important to note that nyctinasty is not exclusive to chestnut and maple trees. Other plants, such as legumes, oxalis, and certain flowers, also exhibit similar leaf movements in response to changes in light and temperature.