Roots develop from these nodes, and a daughter plant is formed. This type of vegetative reproduction is an easy way to increase the size of a strawberry patch. Spider plants also produce stolons, which ultimately can become entirely new plants. Potato tubers, iris rhizomes, and tulip bulbs are underground stems that store food for the plant Figure 8.
It sometimes is difficult to distinguish between roots and stems, but one sure way is to look for nodes. Stems have nodes ; roots do not. In potato tubers , for example, the "eyes" are actually the stem's nodes, and each eye contains a cluster of buds. When growing potatoes from seed pieces, it is important that each piece contain at least one eye and be about the size of a golf ball so there will be enough energy for early growth of shoots and roots.
Rhizomes resemble stolons because they grow horizontally from plant to plant. Some rhizomes are compressed and fleshy e. Johnsongrass is an insidious weed principally because of the spreading capability of its rhizomes. Tulips, lilies, daffodils, and onions produce bulbs , which are shortened, compressed underground stems surrounded by fleshy scales leaves that envelop a central bud at the tip of the stem.
In November, you can cut a tulip or daffodil bulb in half and see all of the flower parts in miniature. After a bulb-producing plant flowers, its phloem transports food reserves from its leaves to the bulb's scales.
When the bulb begins growing in the spring, it utilizes the stored food. For this reason, it is important not to remove the leaves from daffodils, tulips, and other bulb-producing plants until after they have turned yellow and withered. At that time, they have finished producing the food that will be used for next year's flowering. There are two types of bulbs: tunicate and nontunicate Figure 8. Tunicate bulbs e. It helps protect the bulb from damage during digging and from drying out once it is out of the soil.
Nontunicate bulbs e. They are very susceptible to damage and drying out, so handle them very carefully. Corms are another kind of below-ground stem.
Although both bulbs and corms are composed of stem tissue, they are not the same. Corms are shaped like bulbs, but do not contain fleshy scales. A corm is a solid, swollen stem with dry, scale-like leaves. Gladiolus and crocuses produce corms. Some plants e. These stems are short, flat, and enlarged. Buds and shoots arise from the top crown , and fibrous roots grow from the bottom.
Other plants e. However, these are root tissue, not stem tissue, and have neither nodes nor internodes. Stems often are used for vegetative plant propagation. Using sections of aboveground stems that contain nodes and internodes is an effective way to propagate many ornamental plants. These stem cuttings produce roots and, eventually, new plants.
Below-ground stems also are good propagative tissues. You can divide rhizomes into pieces; remove small bulblets or cormels from their parent; and cut tubers into pieces containing eyes and nodes. All of these tissues will produce new plants. Trees generally have one, but occasionally several, main trunks, which usually are more than 12 feet tall when mature.
In contrast, shrubs generally have several main stems, which usually are less than 12 feet tall when mature. Most fruit trees, ornamental trees, and shrubs have woody stems.
These stems contain relatively large amounts of hardened xylem tissue in the central core heartwood or sapwood. Herbaceous or succulent stems contain only a little xylem tissue and usually live for only one growing season.
In perennial plants, new herbaceous stems develop from the crown root-stem interface each year. Canes Figure 9a are stems with relatively large pith the central strength-giving tissue. They usually live only 1 or 2 years.
Examples of plants with canes include roses, grapes, blackberries, and raspberries. For fruit production, it is important to know which canes to prune, how to prune them, and when to prune them. A vine Figure 9b is a plant with long, trailing stems.
Some vines grow along the ground, while others must be supported by another plant or structure. Twining vines circle a structure for support. Some circle clockwise e. Climbing vines are supported either by aerial roots e. The edible portion of several cultivated plants, such as asparagus and kohlrabi, is an enlarged, succulent stem.
The edible parts of broccoli are composed of stem tissue, flower buds, and a few small leaves. The edible tuber of a potato is a fleshy underground stem. And, although the name suggests otherwise, the edible part of cauliflower actually is proliferated stem tissue. A bud is an undeveloped shoot from which leaves or flower parts grow.
The buds of temperate-zone trees and shrubs typically develop a protective outer layer of small, leathery scales. Annual plants and herbaceous perennials have naked buds with green, somewhat succulent, outer leaves. Buds of many plants require exposure to a certain number of days below a critical temperature before resuming growth in the spring.
This period, often referred to as rest, varies for different plants. Forsythia, for example, requires a relatively short rest period and grows at the first sign of warm weather. During rest, dormant buds can withstand very low temperatures, but after the rest period is satisfied, they are more susceptible to damage by cold temperatures or frost.
A leaf bud is composed of a short stem with embryonic leaves. Leaf buds often are less plump and more pointed than flower buds Figure 10a. A flower bud is composed of a short stem with embryonic flower parts. In the case of fruit crops, flower buds sometimes are called fruit buds. This terminology is inaccurate, however; although flowers have the potential to develop into fruits, they may not do so because of adverse weather conditions, lack of pollination, or other unfavorable circumstances.
Buds are named for their location on the stem Figure 10b. Terminal buds are located at the apex tip of a stem. Lateral axillary buds are located on the sides of a stem and usually arise where a leaf meets a stem an axil. In some instances, an axil contains more than one bud. Adventitious buds arise at sites other than the terminal or axillary position.
They may develop from roots, a stem internode , the edge of a leaf blade, or callus tissue at the cut end of a stem or root. Adventitious buds allow stem, leaf, and root cuttings to develop into entirely new plants.
Enlarged buds or parts of buds form the edible portion of some horticultural crops. Cabbage and head lettuce are examples of unusually large terminal buds. Succulent axillary buds are the edible part of Brussels sprouts. In the case of globe artichoke, the fleshy basal portion of the flower bud's bracts is eaten, along with its solid stem.
Broccoli is the most important horticultural plant with edible flower buds. In this case, portions of the stem, as well as small leaves associated with the flower buds, are eaten. The principal function of leaves is to absorb sunlight to manufacture plant sugars through a process called photosynthesis. Leaf surfaces are flattened to present a large area for efficient light absorption.
The blade is the expanded thin structure on either side of the midrib and usually is the largest, most conspicuous part of a leaf Figure A leaf is held away from its stem by a stem-like appendage called a petiole , and the base of the petiole is attached to the stem at a node. Petioles vary in length or may be lacking entirely, in which case the leaf blade is described as sessile or stalkless.
The node where a petiole meets a stem is called a leaf axil. The axil contains single buds or bud clusters, referred to as axillary buds. They may be either active or dormant; under the right conditions, they will develop into stems or leaves. A leaf blade is composed of several layers Figure 12a and Figure 12b. On the top and bottom is a layer of thick, tough cells called the epidermis.
Its primary function is to protect the other layers of leaf tissue. The arrangement of epidermal cells determines the leaf's surface texture. Some leaves, such as those of African violet, have hairs pubescence , which are extensions of epidermal cells that make the leaves feel like velvet. The cuticle is part of the epidermis. It produces a waxy layer called cutin , which protects the leaf from dehydration and disease.
The amount of cutin on a leaf increases with increasing light intensity. For this reason, when moving plants from shade into full sunlight, do so gradually over a period of a few weeks. This gradual exposure to sunlight allows the cutin layer to build up and protect the leaves from rapid water loss or sunscald. The waxy cutin also repels water. For this reason, many pesticides contain a spray additive to help the product adhere to, or penetrate, the cutin layer.
Special epidermal cells called guard cells open and close in response to environmental stimuli, such as changes in weather and light. They regulate the passage of water, oxygen, and carbon dioxide into and out of the leaf through tiny openings called stomata. In most species, the majority of the stomata are located on the underside of leaves.
Conditions that would cause plants to lose a lot of water high temperature, low humidity stimulate guard cells to close. In mild weather, they remain open. Guard cells also close in the absence of light. Located between the upper and lower epidermis is the mesophyll.
It is divided into a dense upper layer palisade mesophyll and a lower layer that contains lots of air space spongy mesophyll. Located within the mesophyll cells are chloroplasts , where photosynthesis takes place. There are many kinds of plant leaves. The most common and conspicuous leaves are referred to as foliage and are the primary location of photosynthesis. However, there are many other types of modified leaves:.
The vascular bundles of xylem and phloem extend from the stem, through the petiole, and into the leaf blade as veins. The term venation refers to how veins are distributed in the blade. There are two principal types of venation: parallel-veined and net-veined Figure In parallel-veined leaves, numerous veins run essentially parallel to each other and are connected laterally by minute, straight veinlets.
Parallel-veined leaves occur most often on monocotyledonous plants. The most common type of parallel veining is found in plants of the grass family, whose veins run from the leaf's base to its apex. Another type of parallel venation is found in plants such as banana, calla, and pickerelweed, whose veins run laterally from the midrib.
In net-veined leaves also called reticulate-veined , veins branch from the main rib or ribs and subdivide into finer veinlets. These veinlets then unite in a complicated network. This system of enmeshed veins makes the leaf more resistant to tearing than does a parallel vein structure. Net-veined leaves occur on dicotyledonous plants. Net venation may be either pinnate or palmate. In pinnate venation, the veins extend laterally from the midrib to the edge e.
In palmate venation, the principal veins extend outward, like the ribs of a fan, from the base of the leaf blade e. Leaves are useful for plant identification. Leaf type Figure 17 also is important for identification. There are two types of leaves: simple and compound. In simple leaves , the leaf blade is a single, continuous unit. Compound leaves are composed of several separate leaflets arising from the same petiole. Some leaves are doubly compound. Leaf type can be confusing, because a deeply lobed simple leaf may look like a compound leaf.
Leaf arrangement along a stem also is used in plant identification Figure There are four types of leaf arrangement:. The leaf blade is the principal edible part of several horticultural crops, including chives, collards, dandelions, endives, kale, leaf lettuce, mustard, parsley, spinach, Swiss chard, and other greens. The edible part of leeks, onions, and Florence fennel is a cluster of fleshy leaf bases. The petiole is the edible product in celery and rhubarb.
As you clean the fireplace, do your plants a favor and sprinkle the ashes in the garden instead of throwing them in the garbage. Oct 22, News story. Gardeners tend to think of fall as the time to put bulbs in the ground, but the warm soil and increasing moisture make it a great time to plant most anything. Information about garden planning, maintenance, cleanup, pest management, houseplants and indoor gardening for the month of November.
Information about garden planning, maintenance and clean up, pest monitoring and management, houseplants, and indoor gardening for the month of October. Kym Pokorny Mar 9, News story. As Oregon gardeners have noticed, our climate is changing. This is primarily due to human activities releasing excessive greenhouse gases into the atmosphere over the last years.
Spider mites are common, tiny garden pests, related to spiders and ticks. Usually microscopic, mites can be found in almost any habitat, including the human body. We refer to some mites based on where they are found: cheese Sep 23, News story. Plus, Extension related news and education. Lists materials needed to build a cloche, then provides step-by-step instructions for building.
Includes color photographs with close-up inserts to show the building process. Want to learn more? Take our online class! Have you ever As more people push to plant in autumn, garden stores are stocking more at the end of summer. Sep 17, News story.
With rain in this weekend's forecast, lots of folks are talking about picking their tomato plants clean. I can't stand the idea of picking all those green tomatoes! Will the rain really ruin tomatoes if we leave them on Grow Your Own At Home!
Fast Plain Box Shipping. Advanced Search Search Tips. Posted on 24th Jun One of the things that hydroponic growers learn as they go along is that plants have different needs in vegetative and flowering cycles.
In the vegetative stages, plants are simply plodding along, developing longer, thicker stems and bigger structures. By contrast, in the flowering stage, they're actually blooming and blossoming and producing their fruits, whatever that may be.
So how do you support plants well in both vegetative and flowering cycles? Some of these ideas relate to providing different kinds of light or different amounts of light in each phase of growing.
When you read a lot about the light cycles that are used in vegetative and flowering phases, you'll find that there's really no one true gold standard for growing. Individuals try different things and work according to what gives them the best results. However, there are some common ideas about the timing cycles of plants should be on in vegetative and flowering phases.
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