Question

Хвоя назначение видоизменения

Answer 1

Хвоя это видоизмененные листья.Имеют вид иголок.Естественно площадь общей поверхности хвоинки гораздо меньше чем площадь поверхности обыкновенного листа.А чем меньше поверхность-тем меньше испарение воды.

Answer 2

The Purpose of Coniferous Needles and Their Modifications

Coniferous trees, such as pine, spruce, and fir, have needle-like leaves instead of broad, flat leaves like deciduous trees. These needle-like leaves, also known as coniferous needles, serve several important purposes for the tree. Let's explore their functions and any modifications they may have.

1. Adaptation to Harsh Environments: Coniferous trees are often found in cold and harsh environments, such as high altitudes and northern latitudes. The needle-like shape of their leaves helps them adapt to these conditions in several ways:

- Reduced Surface Area: The needle shape reduces the surface area of the leaves, minimizing water loss through transpiration and reducing the risk of dehydration in cold and dry climates. - Waxy Coating: Coniferous needles often have a waxy coating, known as a cuticle, which helps to prevent water loss and protect the leaves from freezing temperatures. - Evergreen Nature: Coniferous trees retain their needles throughout the year, allowing them to photosynthesize and continue their metabolic processes even during the winter months when deciduous trees have shed their leaves.

2. Photosynthesis: Coniferous needles play a crucial role in photosynthesis, the process by which plants convert sunlight into energy. Despite their reduced surface area, coniferous needles are highly efficient at capturing sunlight and conducting photosynthesis. They have several adaptations that enable them to carry out this process effectively:

- Chlorophyll Distribution: Chlorophyll, the pigment responsible for capturing sunlight, is distributed throughout the needle's cells, maximizing the absorption of light energy. - Long Lifespan: Coniferous needles have a longer lifespan compared to deciduous leaves, allowing them to continue photosynthesizing for several years. This is particularly advantageous in environments with short growing seasons.

3. Defense Mechanisms: Coniferous needles have also developed certain modifications to protect the tree from herbivores, pathogens, and environmental stressors:

- Resin Ducts: Many coniferous trees produce resin, a sticky substance that flows through specialized ducts in the needles. Resin acts as a defense mechanism against insects, fungi, and other potential threats. - Chemical Compounds: Some coniferous needles contain chemical compounds, such as terpenes, that deter herbivores and inhibit the growth of competing plants.

In summary, coniferous needles serve multiple purposes for the trees that bear them. They help the trees adapt to harsh environments, facilitate photosynthesis, and provide defense mechanisms against various threats. Their needle-like shape, reduced surface area, waxy coating, and other modifications contribute to the overall success and survival of coniferous trees in diverse ecosystems.

I hope this information helps! Let me know if you have any further questions.