part five botany basics: buds
Plant buds are undeveloped or embryonic shoots that arise on the tip of a stem or in the axil of a leaf. Composed of meristem tissue and containing undifferentiated cells, from which different plant structures develop and grow, and fueled by the rapid cell division when conditions are right they are formed in late summer/early fall and remain small and delicate and in most temperate-zone trees and shrubs. In these cooler climates the buds are covered with tough protective scales, formed by modified leaves, that enables them to remain dormant during the winter, whereas, annual and herbaceous perennials have naked buds with green fleshy outer leaves and are very tender. The buds of many plants require a resting or inactive state and exposure to a certain number of days below a critical temperature before they resume growth in the spring.
Forsythia, a deciduous flowering shrub in the Family Oleaceae, requires a relatively short period of rest and grows at the first sign of warm weather, usually early spring. The bloom proceeds the leaves.
photo – Forsythia x intermedia wikipedia
classifications: buds and can be classified in two ways, according to their location on the plant or according to the immature structures within the buds.
A leaf bud is composed of a short stem with embryonic leaves and is vegetative. (Those that contain only immature leaves are called leaf buds, while those buds containing both flowers and leaves in the earliest stages of development are termed mixed buds).
photo – Sycamore wikimedia commons
Flower buds are also composed of a short stem but contain embryonic flower parts and are reproductive. Flower buds on herbaceous plants and on woody plants are made up of undeveloped and tightly packed groups of cells that are the precursors of the various floral parts—petals, stamens, and pistils—with a whorl of sepals or outer leaf bracts covering and protecting the inner parts of the flower bud. Flower buds are sometimes referred to as fruit buds because they can develop into fruit, but only if the right circumstances occur such as pollination, or favorable weather conditions.
By B.traeger – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19401220
location: buds are named for their location on the stem
terminal buds: A terminal bud is located at the apix, or end on a woody twig. It overwinters and grows out during the next spring and summer into a new shoot that extends the length of the twig and may also produce flowers. Some examples of this type of growth are found in apple and cherry blossoms.
photo – black ash, Invasive.org
lateral or axillary buds: These buds are located on the sides of a stem, usually where the leaf meets the stem, or axil, and depending on the cells that developed inside the bud during the previous fall, growth from the lateral bud will produce a branch or a leaf. .
photo – Corylus avellana Wikimedia Commons
adventitious buds: in botany the word adventitious mean something that grows where it would not normally, so in the case of buds, this grow occurs away from the apical meristem in such places as shoots, internodes, edge of a leaf blade, callus tissue, or roots – which can result in a whole new plant. They connect with the phloem and xylem for nourishment, and it is one way that a plant can reproduce asexually. They can grow at anypoint in a plants life and can also facilitate growth if the apical meristem is damaged or removed.
photo – InexpensiveTreeCare.com
buds as food
The enlarged parts or buds from some horticultural crops are edible. Cabbage and lettuce heads are usually terminal buds and brussel sprouts are axillary buds. With the globe artichoke, the solid stem, fleshy basal portion and the flower bracts are consumed.
top left – Gurney’s seeds top right – Seeds for Generations, bottom left – l.fowler, bottom right – Farm Flavor
glossary of terms
Anther – The pollen sac on a male flower
Apex – The tip of a root or shoot
Apical dominance – The tendency of an apical bud to produce hormones that suppress growth of buds below it on the stem
Apical meristem – the growth region in plants found within the root tips and the tips of the new shoots and leaves. Apical meristem is one of three types of meristem, or tissue which can differentiate into different cell types. Meristem is the tissue in which growth occurs in plants.
Axil – The location where leaf joins the stem
Basal plate – bottom of bulb from which roots develop
Bulb – is structurally a short stem with fleshy leaves or leaf bases that function as food storage organs during dormancy
Bolting – plants produce a flowering stem in a natural attempt to produce seeds as a means of survival when under stress.
Cambium – A layer of growing tissue that separates the xylem and phloem and continuously produces new xylem and phloem cells
Chlorophyll – The green pigment in leaves that is responsible for trapping light energy from the sun
Chloroplast – A specialized component of certain cells; contains chlorophyll and is responsible for photosynthesis
Cold hardy – generally measured by the lowest temperature a plant can withstand
Cortex – Cells that make up the primary tissue of the root and stem
Cotyledon – The first leaf that appears on a seedling. also called a seed leaf.
Corms – bulbo-tuber, or bulbotuber is a short, vertical, swollen underground plant stem that serves as a storage organ that some plants use to survive winter or other adverse conditions such as summer drought and heat
Cuticle – A relatively impermeable surface layer on the epidermis of leaves and fruit
Dermal tissue – covers the outer surface of herbaceous plants. It is composed of epidermal cells, closely packed cells that secrete a waxy cuticle that aids in the prevention of water loss
Dicot – having two seed leaves
Herbaceous – vascular plants that have no persistent woody stems above ground
Epidermis – The outermost layer of plant cells
Fibrous roots – a network of feeding lateral roots found on most plants
Ground meristem – an area of primary meristematic tissue, emerging from and immediately behind the apical meristem, that develops into the pith and the cortex
Guard cell – Epidermal cells that open and close to let water, oxygen and carbon dioxide pass through the stomata
Internode – the space between nodes on a stem
Lateral root – roots that branch from larger primary roots
lenticel: small, oval, rounded spots upon the stem or branch of a plant that allow the exchange of gases with the surrounding atmosphere
Marginal meristems – the meristem located along the margin of a leaf primordium and forming the leaf blade. The apical meristem or growing tip, is a completely undifferentiated meristematic tissue found in the buds and growing tips of roots in plants.
Meristem – Specialized groups of cells that are a plant’s growing points.
Meristematic zone – located at the tip of a root and manufactures cells: it is an area of cell division and growth
Mesophyll – A leafs inner tissue, located between the upper and lower epidermis; contains chloroplasts and other specialized cellular parts (organelles)
Monocot – having one seed leaf
Mycorrhizae – symbiotic association between certain fungi and roots of a plant
Node – an area on a stem where a leaf, stem, or flower bud is located
Ovary – The part of a female flower where the eggs are locate
Periderm – the outer layer of plant tissue: the outer bark
Petiole – The stalk that attached a leaf to the stem
Phloem – Photosynthate-conducting tissue
Pistil – The female flower part; consists of a stigma, style, and ovary
Pith – or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant. … In trees pith is generally present in young growth, but in the trunk and older branches the pith often gets replaced – in great part – by xylem
Primary root – originating at the lower end of a seedlings embryo and continues to elongate downward. It may or may not persist into plant maturity, and has limited branching – it is called a tap root
Procambium – is a meristematic tissue concerned with providing the primary tissues of the vascular system; the cambium proper is the continuous cylinder of meristematic cells responsible for producing the new vascular tissues in mature stems and roots
Protoderm – The primary meristem in vascular plants that gives rise to epidermis. Also called dermatogen
Respiration – the process of converting sugars and starches to energy
Rhizomes – is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow horizontally. The rhizome also retains the ability to allow new shoots to grow upwards
Root cap – group of cells protecting the apical meristem at the root tip
Root hairs – delicate, elongated epidermal cells that occur in a zone behind the root’s growing tip with the function of increasing the roots surface area and absorptive capacity
Root plate – That part of the root system (excluding the small outermost roots) needed to keep a tree wind-firm.
Stamen – The male flower part; consists of an anther and a supporting filament
Stigma – The top f a female flower part; collects pollen
Stoma (pl. stomates, stomata) – tiny openings in the epidermis that allow water, oxygen, and carbon dioxide to pass into and out of a plant
Suberin – a waxy material found in bark that can repel water
Style – The part of a female flower that connects the stigma to the ovary. Pollen travels down the style to reach the ovary, where fertilization occurs
Tap root – see Primary root
Transpiration – the process of losing water (in the form of vapor) through stomata
Tuber – enlarged structures in some plant species used as storage organs for nutrients. They are used for the plant’s perennation, to provide energy and nutrients for regrowth during the next growing season, and as a means of asexual reproduction. Stem tubers form thickened rhizomes or stolons
Tunic – skin-like covering that protects the fleshy scales
Turgor – Cellular water pressure; responsible for keeping cells firm
Vascular tissue – Water, nutrient, and photsynthate-conducting tissue (xylem and phloem)
Vegetative structures – The vegetative (somatic) structures of vascular plants include two major organ systems: (1) a shoot system, composed of stems and leaves, and (2) a root system
Xylem – Water and nutrient-conducting tissue
Zone of elongation – located behind the meristem. Cells in this area increase in size through food and water absorption. As they grow, they push the root through the soil
Zone of maturation – located directly beneath the stem. Cells in this zone become specific tissues such as epidermis, cortex, or vascular