phloem

简明释义

英[ˈfləʊem]美[ˈfloʊem]

n. （植）韧皮部；筛部

英英释义

单词用法

同义词

反义词

例句

1.The stele includes all primary tissues derived from the procambium consists of pericycle, phloem and xylem .

中柱包括从原形成层衍生而来的全部初生组织，由中柱鞘、韧质部和木质部组成。

2.Bicollateral bundle the arrangement of tissues in the vascular bundles in which the phloem is situated on both sides of the xylem.

是初生木质部的内，外方都有初生韧皮部分布的一种维管束排列方式。

3.In the transection section, the area of secondary phloem is much larger than secondary xylem.

在横切面上，次生韧皮部的面积比次生木质部大得多。

4.The stele includes all primary tissues derived from the procambium consists of pericycle, phloem and xylem.

中柱包括从原形成层衍生而来的全部初生组织，由中柱鞘、韧质部和木质部组成。

5.Primary phloem PHLOEM derived from the procambium in the young plant.

初生韧皮部：指幼嫩植物中来源于原形成层的韧皮部。

6.In the bark of tapped trees, the thickness of the conducting phloem is less than 1 mm.

在割胶树的树皮中，有输导功能的韧皮部的厚度不超过1毫米。

7.The secondary phloem consisted of sieve cells and phloem parenchymas.

根的次生韧皮部则由筛胞和韧皮薄壁细胞组成。

8.This had similar mercury levels to the phloem.

树皮的汞含量与韧皮部相近。

9.So the aloin cells were special phloem parenchyma cells because they Shared the same origin with the other phloem cells.

据此，芦荟叶维管束内的大型薄壁细胞的来源与韧皮部相同，属于特化的韧皮部薄壁组织细胞。

10.The phloem transports sugars produced by photosynthesis to various parts of the plant.

这韧皮部将光合作用产生的糖运输到植物的各个部分。

11.In some plants, the phloem is responsible for transporting hormones as well.

在某些植物中，韧皮部也负责运输激素。

12.Damage to the phloem can severely affect a tree's growth and health.

对韧皮部的损伤会严重影响树木的生长和健康。

13.The phloem and xylem work together to ensure the plant's survival.

韧皮部和木质部共同作用以确保植物的生存。

14.Researchers study the phloem to understand nutrient distribution in plants.

研究人员研究韧皮部以了解植物中的营养分布。

作文

In the study of plant biology, understanding the structure and function of various plant tissues is crucial. One of the most important tissues in vascular plants is the phloem, which plays a vital role in the transportation of nutrients. The phloem is primarily responsible for transporting the products of photosynthesis, mainly sugars, from the leaves to other parts of the plant where they are needed for growth and energy. This process is essential for the survival of plants, as it ensures that all parts receive the necessary nutrients to function effectively.The structure of the phloem is quite fascinating. It consists of several types of cells, including sieve elements, companion cells, and phloem fibers. Sieve elements are specialized cells that form the main conduits for the transport of sugars. These cells are arranged end to end, creating long tubes that facilitate the movement of nutrients. Companion cells, on the other hand, are closely associated with sieve elements and help in the loading and unloading of sugars into the phloem. The presence of these two cell types is crucial for the efficient functioning of the phloem system.One might wonder how the phloem manages to transport substances over long distances within the plant. The answer lies in a process called translocation. During translocation, sugars produced in the leaves during photosynthesis are actively transported into the phloem. This creates a concentration gradient that allows water to move into the phloem through osmosis, generating pressure that pushes the sap (a mixture of sugars and other nutrients) through the plant. This process is not only essential for nutrient distribution but also helps maintain the overall health of the plant.Moreover, the phloem is dynamic and can adapt to the needs of the plant. For instance, during periods of rapid growth or stress, the phloem can increase its activity to ensure that the growing tissues receive sufficient nutrients. Conversely, during times of dormancy, the phloem may reduce its activity, conserving resources for when they are most needed.In addition to its nutritional role, the phloem also serves other important functions. It is involved in the transport of signaling molecules that help coordinate growth and responses to environmental stimuli. For example, when a plant is under attack from pests, the phloem can transport defensive compounds to various parts of the plant, helping to protect it from damage.Understanding the role of the phloem is not only important for botanists and ecologists but also has practical implications for agriculture and horticulture. By enhancing our knowledge of how the phloem functions, we can develop better strategies for improving crop yields and ensuring food security. For instance, researchers are exploring ways to manipulate the phloem to enhance nutrient transport in crops, which could lead to more resilient and productive plants.In conclusion, the phloem is a crucial component of plant biology, playing a significant role in nutrient transport, growth regulation, and defense mechanisms. Its complex structure and dynamic nature make it a fascinating subject of study, with implications that extend beyond the realm of botany. As we continue to explore the intricacies of the phloem, we uncover new opportunities to improve agricultural practices and enhance our understanding of plant life as a whole.

在植物生物学的研究中，理解和掌握各种植物组织的结构和功能至关重要。在维管植物中，最重要的组织之一是韧皮部，它在营养运输中发挥着重要作用。韧皮部主要负责将光合作用的产物，主要是糖，从叶子运输到植物的其他部分，以满足生长和能量的需求。这个过程对植物的生存至关重要，因为它确保所有部分都能获得所需的营养素以有效运作。韧皮部的结构相当迷人。它由几种类型的细胞组成，包括筛管元素、伴胞和韧皮纤维。筛管元素是专门的细胞，形成糖运输的主要通道。这些细胞端对端排列，形成长管道，便于养分的移动。伴胞则与筛管元素紧密相关，帮助将糖装载和卸载到韧皮部中。这两种细胞类型的存在对韧皮部系统的高效运作至关重要。人们可能会想知道，韧皮部如何能够在植物内运输物质。答案在于一种称为转运的过程。在转运过程中，叶子在光合作用中产生的糖被主动运输到韧皮部中。这会产生浓度梯度，使水通过渗透作用进入韧皮部，产生压力，推动液汁（糖和其他养分的混合物）在植物内流动。这个过程不仅对养分分配至关重要，而且有助于维持植物的整体健康。此外，韧皮部是动态的，可以适应植物的需求。例如，在快速生长或压力期间，韧皮部可以增加其活动，以确保生长组织获得足够的营养。相反，在休眠期，韧皮部可能会减少活动，以节省资源，以备最需要时使用。除了营养角色外，韧皮部还具有其他重要功能。它参与运输信号分子，帮助协调生长和对环境刺激的响应。例如，当植物受到害虫攻击时，韧皮部可以将防御化合物运输到植物的各个部分，帮助保护其免受损害。理解韧皮部的作用不仅对植物学家和生态学家重要，还有实际意义，对农业和园艺也有影响。通过增强我们对韧皮部功能的了解，我们可以制定更好的策略来提高作物产量，确保粮食安全。例如，研究人员正在探索操控韧皮部以增强作物中的营养运输的方法，这可能导致更具弹性和生产力的植物。总之，韧皮部是植物生物学的重要组成部分，在营养运输、生长调节和防御机制中发挥着重要作用。其复杂的结构和动态的特性使其成为一个引人入胜的研究对象，其影响超越了植物学的领域。随着我们继续探索韧皮部的复杂性，我们发现了改善农业实践和增强我们对植物生命整体理解的新机遇。