plants consist of organs tissues and cells each
of them is a specific structure that allows them to perform a particular set of functions
that help the plant to survive this video will cover plant organs and plant organ systems also
known as the root system and the shoot system okay here we go to begin we should clarify what
we generally mean when we refer to organ systems organs tissues and cells it's important to
be familiar with these terms in order to understand how each structure contributes
to the plant a group of organs that work together is called an organ system in humans a
familiar example might be the digestive system in the digestive system many organs work together
to obtain energy from food in Plants the so-called shoot system involves many structures like
stems branches and leaves which collaborate to allow the plant to harvest energy from the
Sun organs are a collection of tissues that plants are multicellular eukaryotic organisms
most Survive by absorbing water and nutrients from their environment and by harnessing energy
from the Sun in a process known as photosynthesis plants are generally split into two major
categories non-vascular plants and vascular plants non-vascular plants such as mosses hornworts
and liverworts do not have a system of xylem and phloem tubes to transport materials around the
plant because they must rely on diffusion these plants tend to be smaller and to have simpler
tissues and structures many of these structures are only a few cells thick because diffusion can
only occur effectively over very short distances while they can sometimes have structures that
somewhat resemble leaves stems or Roots they're not considered to be true leaves stems or Roots
because they lack these crucial Transportation structures this video will focus mainly on
vascular plants and their specialized organs and organ systems vascular plants have two major
organ systems the root system and the shoot system the root system is usually mostly underground
it supports the plant and absorbs water and minerals from the environment the shoot
system generally grows above ground which allows some parts of it to absorb the
light needed to perform photosynthesis we'll now discuss each major organ system
in detail beginning with the root system The Roots have three major functions anchoring
the plant to the soil absorbing water and minerals and transporting them upwards to the rest of the
plant and storing the products of photosynthesis some types of roots can also perform
gas exchange and a few types of plants have adventitious Roots which are
at least partially above ground the root system consists of primary
secondary and sometimes even tertiary roots in addition to root hairs which
help to increase their surface area the last centimeter or so of the root is where
cell division occurs there are three major zones the zone of cell division where new cells are
formed and if you've looked at onion root tips while studying mitosis in class this is likely
the area you observed the zone of elongation where the new cells stretch an increase in
length causing the root to get longer and the zone of maturation where cells specialize
or differentiate into their unique roles at the very end of the root is the
root cap which contains organelles that perceive gravity and allows the main
root to grow down rather than at random there are two major types of
roots tap roots and fibrous roots taproots have one major root that grows
straight down sometimes with a few smaller branches protruding off of it it looks a
bit like a carrot and in fact carrots beets dandelions parsnips and Jicama are all examples
of Taproot plants tap roots are advantageous in dry environments because they can reach far
down into the soil to reach water of course this also makes them much harder to harvest or
remove for instance think about how difficult it is to remove dandelions from your lawn typically
dicots have taproots and some taproots like those found in carrots jicama or beets also function
as a storage space for sugars and starches fibrous Roots have a network of smaller
roots that protrude outwards usually at a much shallower level these can be excellent
at helping them to prevent soil erosion and are typical of monocots such as grasses now
let's move on to the shoot system which consists of stems leaves fruits and flowers
or basically any structure that is not a root stems are part of the shoot system of the plant
they provide support and also connect the leaves where photosynthesis occurs with the roots where
some of the products are stored stems come in many shapes and sizes and can be soft Woody branched
or unbranched stems also contain nodes which are the attachment points for both leaves and flowers
the areas between the nodes are called internodes leaves are the major site of photosynthesis their cells contain chloroplasts which harness
energy from sunlight to produce sugars chlorophyll the pigment inside the chloroplasts
of the leaves is what makes most leaves green leaves come in many shapes and sizes Each of which
is specifically suited to its environment for instance plants in hot dry environments often have
spiky leaves or needles to help reduce water loss in addition some plants such as succulents store
water in their Leaf tissues if you'd like a more detailed view of the Interior structure of
leaves I've left a link in the video description flowers and or fruits are related organs that are
both part of the plant's reproductive system the three female plant structures the ovary the
style and the stigma are collectively known as the carpal flowers contain both male and
female gametes pollen and ovules respectively but many plants can't self-fertilize to
get around this problem some exchange gametes by attracting pollinators who will
transfer pollen from one plant to another fruits are structures containing seeds which
form from the ovary at the base of the flower once it has been fertilized notice how the
structures of fruits and flowers are quite similar after the ovules are fertilized the petals drop
away and the ovary swells and grows into a fruit containing the seed or seeds apples bell peppers
pea pods cucumbers eggplants squashes and more are technically all fruits this is because they
developed from the mature center of the flower so in summary vascular plants have two major
organ systems the root system and the shoot system within each organ system there are a
number of useful structures that help the plant to absorb what it needs from its
environment and or to perform photosynthesis if you found this video helpful please
consider subscribing to my channel and checking out some of my other videos
thanks again for watching see you next time