Scribd
Upload
831 views2 pages

Plant Histology

This document provides an overview of plant tissue structures and types. It describes the location and composition of meristematic tissue, which contains undifferentiated cells important for plant growth and propagation. It then details the typical structures found in roots, including the epidermis, cortex, endodermis, pericycle, vascular system, and differences between monocot and dicot roots. The document also discusses common stem and leaf structures, noting variability between species. The objective is to prepare and identify onion epidermal cells, identify different plant tissues, and compare monocot and dicot tissue distribution. Histology supports the study of cell biology and is important for disease diagnosis.

Uploaded by

Nurul Rayhana
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
831 views2 pages

Plant Histology

This document provides an overview of plant tissue structures and types. It describes the location and composition of meristematic tissue, which contains undifferentiated cells important for plant growth and propagation. It then details the typical structures found in roots, including the epidermis, cortex, endodermis, pericycle, vascular system, and differences between monocot and dicot roots. The document also discusses common stem and leaf structures, noting variability between species. The objective is to prepare and identify onion epidermal cells, identify different plant tissues, and compare monocot and dicot tissue distribution. Histology supports the study of cell biology and is important for disease diagnosis.

Uploaded by

Nurul Rayhana
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 2

INTRODUCTION

Plant tissue growth involves the cell division (hyperplasia) of undifferentiated cells (parenchyma) and the
growth (hypertrophy) of more differentiated cells. The location of proliferative undifferentiated or
dedifferentiated cells in so-called meristematic tissue is of great interest to the horticulturist engaged in plant
propagation for commercial or research purposes. Meristematic tissue is most often associated with shoot and
root tips (apical meristems). Longitudinal sections allow for the characterization of various cell layers relative to
the plant surface. In some plants meristematic tissue may also be found near nodes (intercalary meristem). A
typical root is comprised of an outer cortex bounded on the outside by an epidermis and on the inside by an
endodermis. The epidermis is usually a thin monolayer; however aerial roots of epiphytes have a thick multilayered epidermis for absorbing water quickly from rain. Botanists typical recognize two forms of cortex. Solid
cortex is composed of compact parenchymal cells with very little intracellular space, while lacunae cortex
contains large air spaces sandwiched between layers of denser cortex. It is thought that a lacunae cortex confers
an advantage in dense (often soaked) soil, while a solid cortex is more common in well-drained soils. The
endodermis typically contains cells with thicker, more lignified (stains well with Safranin O). The inside of the
root typically contains a vascular system bounded by a pericycle containing plain, thin-walled cells. The
vascular system of monocot roots normally consists of a ring of about six large xylem vessel elements
(tracheid). In dicots, there are usually two, three, or four (in rare cases as many as six) bundles of xylem. The
phloem is normally present in a ring surrounding the xylem elements. The stem , like roots contains a epidermis
and cortex but often lack the distinct endodermis visible in root sections. The vascular bundles are arranged in
an ordered ring in dicots and gymnosperms, but monocots may possess multiple rings or the vascular bundles
may appear scattered throughout the cortex. The mint family (Lamiaceae) has characteristic square stems. The
sedges (Carex genus) are known for triangular stems. The central parenchymal cells may be lignified (stain with
safranin O). Leaf tissue architechture shows great variability between species. There is no such thing as a
typical leaf. For this reason leaf structure and histology may be used for taxological purposes. Only in very
general ways do all leaves have common histological features: an epidermis with stomata, chloroplast-rich
photosynthetic mesophyll, and vascular tissue.

OBJECTIVE
1. to prepare and identify the onion epidermal cells
2. to identify different types of plant tissues
3. to compare the structure and distribution of tissues in monocots and dicots

Conclusion
The relationship between the function of cells and organs is reflected in the organisation of tissues,
visualised under the microscope. Hence histology supports the study of cell biology at all levels.
Histology is also very important in diagnosis of disease and hospitals have associated laboratories and
systems for examining and reporting on tissue resections and biopsies.

You might also like