The program is not working correctly.
The program is not functioning properly. ess phloem cells take over they transport sugar from the leaves to the rest of the plant and these cells are living unlike xylem they don’t die to form pipes instead they stay alive and flexible kind of like a bunch of tiny slinky toys squished together phloem cells also help transport hormones and signals to other parts of the plant like when a branch is damaged and the plant needs to know to send resources to the wound and finally we have ground tissue which is everything in between the skin and the veins this tissue is made up of cells that do all sorts of things like photosynthesis and storage they’re like the plant’s factory workers and the cells in this tissue can change shape and size to meet the plant’s needs for example when a plant needs to make more leaves the ground tissue cells in the stem divide and differentiate into new cells that will become leaves and when a plant needs to store energy it can turn its ground tissue cells into fat cells and fill them with energy-rich starch
In 1924, Dr. Catherine Esau was working on a sugar beet farm in California where some of the beet plants were suffering from a strange virus called Curly Top Disease, spread by insects called leaf hoppers. This virus causes plants to have unusually curly leaves and stunts their growth. By paying careful attention to the anatomy or the internal structure of these plants, Esau discovered how the disease spread throughout the plant. She wrote in her autobiography, “I began to realize the virus must enter and must move in the plant along a pathway. I figured out that if the leaf hopper passes the virus by feeding, then the virus must be moving through the same system as the food moves. In other words, the very same group of cells that move the sugar produced by photosynthesis from the leaves to the rest of the plant was being hijacked to transport the virus all throughout it.” This discovery was huge for the field of botany because it helped illustrate just how essential the knowledge of healthy plant anatomy is for understanding unhealthy plants and helping them get better.
So, stick out your tongue and say “ahh” – plants, let’s explore what’s going on in there! Hi, I’m Alexis and this is Crash Course Botany. Just like human bodies, plant bodies are made up of tissues, which are organized groups of cells that have similar structures and functions. They do everything from transporting nutrients throughout a plant’s body to making fruit taste delicious. And just like in our bodies, different tissues work together to make organs function. But in plant bodies, those organs aren’t hearts and lungs – they’re stems, leaves, and roots.
So, let’s zoom in on the stars of today’s show – please welcome dermal tissue, the plant’s skin; vascular tissue, the plant’s veins; and ground tissue, everything in between.
Let’s start with the skin – the dermal tissue covers the entire outside of the plant, forming the epidermis, which is coated in a layer of wax called a cuticle. This outer layer prevents water from escaping and nasty things like viruses from getting inside. In other words, the cuticle runs a constant skin care routine for the plant, keeping it moisturized and free of gross stuff. No wonder plants don’t get zits! But they do have pores – tiny openings in the epidermis of leaves called stomata – let in carbon dioxide gas, a key part of photosynthesis. And personally, I love that stomata look like creepy little mouths. I mean, they may look like aliens, but this image could easily be from a tree in your backyard.
Plants also get little hairs sprouting out of their skin called trichomes, and like hairdos, there are trichomes for every occasion. Some protect against plant-eating animals by secreting itchy toxins from the leaf or stem epidermis – which, if you’ve ever run into stinging nettle, you are already painfully familiar with. Others act like sunscreen and protect the plant from solar radiation, or form a blanket to keep the plant warm during the freezing winter. Meanwhile, the root epidermis produces billions of trichomes to suck up water in the soil. One study estimated that if you strung the root hairs of a single rye plant end to end, it’d be 11,000 kilometers long – that’s a ponytail stretching a quarter of the way around the earth, Ariana Grande!
While we can observe a plant’s skin on the outside, we’ll have to peer inside to explore its other tissues. Next up, vascular tissue, which forms the circulatory system, or veins, of the plant. Its cells are specialized for transportation – like our subway system moves people where they need to go – and there are two main types of cells that make up vascular tissue: xylem and phloem.
Xylem cells transport water and nutrients from the roots to the leaves, and get this – the