之间的区别Primary and Secondary Growth

这关键区别在初级和继发增长之间是primary growth increases the length of roots and shoots as a result of细胞分裂在初级分生生物中，由于次生分生组织中的细胞分裂，二次生长会增加植物的厚度或周长。

初级和继发生长使植物的大小 - 长度和厚度增加。Apical and lateral meristems负责植物生长。当顶端分生组织的细胞分裂时，会发生初级生长。相反，当侧分生组织的细胞分裂时，发生二次生长。初级生长是造成长度的增加，而继发生长则导致植物周长的增加。

CONTENTS

1。概述和关键差异
2。什么是初级增长
3。What is Secondary Growth
4。初级和次要增长之间的相似之处
5.Side by Side Comparison – Primary vs Secondary Growth in Tabular Form
6.Summary

什么是初级增长?

主要增长的植物是increas的过程ing the length of the shoots and roots. It occurs as a result of the cell division in primary meristems such as apical meristem, intercalary meristem, and intrafascicular cambium. Shoot apex is dome-shaped with leaf primordia. There are axillary buds, nodes, and internodes. Moreover, the apex has three distinct regions. At the very top is the region of cell division where only cell division takes place. Next to that, there is a region of cell enlargement. Behind this region is the region of cell differentiation where each cell becomes fully specialized for its particular function.

Furthermore, three types of basic分生组织发生在茎尖。它们是原生胚层，前膜和地面分生组织。Procambium是一系列纵向奔跑的链。在横截面中，它们以断戒指的形式出现。丙蜜邦会产生原发性血管组织。第一个形成的细胞是内部的素细胞，而原始的细胞则是原始的。此外，素氧基通常仅具有木质素的环形和螺旋增厚，从而延伸。其他增稠剂仅在伸长后发生。此外，素的空腔小得多。protoxylem和Protopheem很快变得无活跃。 Their function is taken over later by developing metaxylem and metaphloem.

什么是次要增长？

After primary growth, lateral meristem becomes active and results in the formation of secondary permanent tissues. It is called secondary growth. The lateral meristems are the lateralvascular cambium and cork cambium。它们仅在迪科特（Dicots）上形成。在单子叶植物中，没有化合物。因此，没有二次增长。由于继发性生长，茎和根的厚度或周长有所增加。在茎中，颅骨内形成型变得活跃，并切断细胞到外部和内部。切断向外部的细胞成为次生韧皮部，而内部的细胞变成二木。

In the meantime,parenchyma cellsbetween adjacent vascular bundles also become meristematic and form the interfascicular cambium. The intrafascicular cambium and the interfascicular cambium join to form a cambial ring, which is the vascular cambium. The interfascicular cambium cuts off cells to the outside and inside. The outside cells become the secondary phloem while inside cells become the secondary xylem. The cambium contains fusiform initials and ray initials. Fusiform initials give rise to normal xylem and phloem. Ray initials give rise to parenchyma, which forms medullary rays.

As the numbers of cell layers inside increase, the cells outside become compressed and this results in the formation of another lateral meristem in the outer layers of the cortex. These become a ring of cork cambium. Cork cambium cuts off cells to the inside and outside. Cells that are cut off to the outside become suberized and form the cork. Cells that cut off to the inside form secondary cortex.

初级和次要增长之间有什么相似之处？

• Primary and secondary growth happen in plants, and they allow plants to increase in size permanently.
• Furthermore, primary and secondary growth occur as a result of the rapid cell division in the meristematic tissues.
• Additionally, in woody plants, primary growth is followed by secondary growth.

What is the Difference Between Primary and Secondary Growth?

主要生长是增加植物长度的过程，而二次生长是增加植物周长的过程。因此，这是初级和二级增长之间的关键区别。初级生长和次要生长之间的另一个差异是，主要生长是主要分生组织中细胞分裂的结果，而继发生长是次生分生组织中细胞分裂的结果。

Below infographic shows more details on the difference between primary and secondary growth.

Summary – Primary vs Secondary Growth

植物以两种方式生长：初级生长和继发生长。初级生长是植物长度的增加。相反，次要生长是植物周长的增加。此外，包含未分化细胞的分生组织组织负责初级和二级生长。初级生长是由于原发性分生组织中细胞分裂的结果，主要是在位于根和射击尖端的顶端分生组织中，而次生生长是由于次生分生组织中的细胞分裂而发生的，例如软木塞和血管性化和血管形成症。木本植物。因此，这总结了初级和次要生长之间的差异。

参考：

1.“ 30.2c：茎中的初级和二级生长。”生物学库，库，2018年7月16日，在这里可用。
2。“Plant Development II: Primary and Secondary Growth.” Biology 1520, 19 Feb. 2018,在这里可用。

图片提供：

1。“Apical Meristem in Allium Root Tip” By Berkshire Community College Bioscience Image Library (Public Domain) viaFlickr
2. Chiswick Chap的“树二级生长图” - 自己的作品（CC BY-SA 4.0）通过下议院维基梅迪亚