The Plant: A Quick Crash Course

By: Nancy Zepeda

@missmmjgeek

I. THE PLANT: CELLS, TISSUES (DERMAL/VASCULAR/GROUND), AND ORGANS (ROOTS/STEM/LEAVES)

Thanks to roots, stems, and leaves, plants are able to attain water, minerals, CO2, and light. Most vascular plants acquire their resources from two environments, one being below ground where they draw water and minerals and the other being above ground where they capture CO2 and light.

A. CELLS= the building blocks of life! The five major types of plant cells are:

1. Parenchyma cells- photosynthesis (food manufacturing) occurs within parenchyma cells in leaves. Some of these cells have the ability to store yummy reserves like starch in stems and roots. Snapped your plant? No problem! During wound repair these cells have the ability to divide and become other types of cells.
2. Collenchyma cells- a flexible plant cell that helps support, without restraining growth, developing parts of the plant.
3. Sclerenchyma cells- far more rigid than collenchyma cells, sclerenchyma cells serve to strengthen and support plants. You can find mature sclerenchyma cells in regions of the plant that have stopped growing.
   1. Hemp fibers, an example of sclerenchyma fibers, are commercially used to produce rope and often blended with other fibers to create fabrics.
4. Tracheids & Vessels (water conducting cells of the xylem)- once dead, these cells leave behind thickened cell walls that form a nonliving conduit like carcass through which water can flow.
5. Sieve cells (sugar conducting cells of the phloem)- unlike the water conducting cells, these sugar conducting cells are alive during maturity. Sugars and other nutrients are transported through long, narrow cells called sieve cells.

B. TISSUES= a group of cells serving a common function.

1. Dermal tissue system- the outer protective covering that defends against physical damage, pathogens and alongside the cuticle (a waxy coating on the epidermal surface) helps in the prevention of water loss.
   1. Epidermis- a single layer of tightly packed cells.
      1. Root hair- is a thin, tubular extension of a root epidermal cell.
         1. 

            All that root hair fuzzzzzzzzz!

      2. Trichomes- hairlike outgrowths from the epidermis. Trichomes help reflect excess light and deter insects through sticky and toxic secretions.
         1. 

            Dosidos dripping with tall trichomes.

   2. Periderm- a secondary protective layer that replaces the epidermis in older regions of stems and roots.
2. Vascular tissue system- transports materials between the root (consisting of roots) and shoot (consisting of stems and leaves) systems. Roots absorb and provide essential water and minerals to the shoot system which can then return the favor via photosynthates (sugars and other carbohydrates produced during photosynthesis) to the nonphotosynthetic roots that would otherwise starve.
   1. Xylem- consists mainly of tubular, elongated dead cells that transport water and minerals upward from the roots into the shoots. Recall the water conducting cells of the xylem and the water conduit carcass mentioned earlier?
   2. Phloem-consists of living cells arranged into elongated tubes that transport sugar and other organic nutrients to roots and sites of growth ( such as developing leaves and fruits).
3. Ground tissue system- made up of parenchyma, collenchyma and sclerenchyma cells that function in storage, support and carrying out photosynthesis.

C. ORGANS= consists of several types of tissues that together carry out particular functions.

1. Roots- a multicellular organ that absorbs water and minerals, anchors a vascular plant in soil and often stores sugars and starches for consumption during flowering and fruit production.
   1. 

      A successfully rooted cutting.

   2. Taproot system- most flowering and seed producing plants, cannabis included, have a taproot system made up of one main vertical root termed the taproot. Taproots give rise to lateral roots. Root hairs should not be confused with a lateral root which is a multicellular organ. Remember, root hairs are extensions of an epidermal cell. They are short-lived, constantly replaced, and contribute little to plant anchorage.
      1. 

         Taproots giving way to adorable little cannabis seedlings.

   3. Fibrous root system- a mat of thin roots spreading out underneath the soil’s surface, with no single root functioning as the main one. Instead of a taproot, various small roots grow from the stem or even leaves. Each small root forms its own lateral roots.
2. Stems- consisting of an alternating system of nodes (the point where leaves are attached) and internodes (the stem segments between nodes) that support the leaves and reproductive structures.
   1. 

      Stem of a CheeseXBBP

3. Leaves -the main photosynthetic organ. Some species have leaves with adaptations enabling them to perform additional functions such as support, protection, storage or reproduction.
   1. 

      Me holding hands with a Kushmints leaf.

Alright, now that we’ve briefly reviewed the cells, tissues, and organs of a plant let’s dig a little deeper into metabolism, sexing, and breeding…