BOTANY [BIO421] Chapter 6 - Tissues and the Primary Growth of Stem PDF

BOTANY [BIO421] Prelim Period Palm trees - large, perennial (lived Chapter 6 - Tissues and hundreds of years), no woods, giant herb...

BOTANY [BIO421] Prelim Period Palm trees - large, perennial (lived Chapter 6 - Tissues and hundreds of years), no woods, giant herb Meristems = embryonic tissues that is the Primary Growth of the center of mitoctic cell division where plant grows occurs. Stem Introduction The body of the herb consists of three basic parts: leaves, stem, and roots. Stems - primary transport and support; produce leaves and hold them to sunlight; sugar and nutrients storage (winter); means of survival (remains alive - dead leaves) and dispersal (spread as runner or vines) Some flowering plant parts have been modified. (eg. cacti - appears leafless Basic Types of Cells and Tissues but has small green leaves 100 to 1000 micrometers) Three classes based on the nature of their In each plant described becomes walls: highly modified by natural selection, permitting survival in unusual habitats. Angiosperms - flowering plants; division Magnoliophyta Basal Angiosperms - lineage from most flowering plants (eg. waterlilies) Eudicots - broadleaf plants (eg. roses); two cotyledons Monocots - grasses, palms, etc.; one cotyledon Difference of two is their division; tricolpate pollens 1) Parenchyma (PC) Cotyledon - first, fleshy leaves that Parenchyma cells - have only enveloped the embryo as it grew; first primary walls that are thin. part of plant from the seed. Parenchyma tissues - the Plant bodies have two fundamental mass of parenchyma cells types: primary plant body most common type and soft (herbaceous) and secondary plant parts of a plant body (woody) Actively metabolically Herb - a plant never woody and (performed metabolic reaction covered with bark (outermost layer); catalyzed by enzymes) and lived less than a year; tissue = primary remain alive after mature. tissues Types of Parenchyma Trees and shrubs = secondary tissues a) Chlorenchyma cells - involved in photosynthesis, many chloroplasts, 1 BOTANY [BIO421] Prelim Period and thin walls to allow light and Provides support; if collenchyma-rich carbon dioxide. tissue is cut off from its water supply, b) Glandular cells - secrete nectar, collenchyma would not be able to fragrances, mucilage, resins, and oils; support stem and need parenchyma in few chloroplasts but elevated amounts the inner tissues. of dictyosomes (golgi apparatus) and ○ Collenchyma and turgid endoplasmic reticulum; transport large parenchyma work together quantities of sugar and minerals, like air pressure; tendency of transform metabolically, and transport parenhcyma to expand relies out. on collenchyma resistance; c) Transfer cells - mediate short-distance thus stem becomes rigid and transport of materials using a large, grows. extensive plasma membrane capable Require more glucose for their of holding numerous molecular production since they are thick pumps; cannot form folds, instead Produced only in shoots and young transfer cells increase their surface petiole area by having extensive knobs. Aerial roots of epiphytes have a thick layer of collenchyma. Some cells function by dying at maturity. 3) Sclerenchyma (SC) ○ Stamens must open and Sclerenchyma cells - both primary release pollen/seeds; formed wall and thick secondary wall (always by parenchyma cells that die lignified - rigid or woody) and break down. Some form Walls are elastic; can be deformed and large spaces to allow gasses turn back to original shape to diffuse; some of their Develop from parenchyma cell’s protoplasm is converted mature organ after they have stopped metabolically to mucilage. growing. Also conduct nutrients over long If mature organ had collenchyma for distance phloem support, they would reshape Little glucose needed to build constantly by storms/animals (not cellulose and hemicellulose of thin optimal) walls (80 - 100 nm thick, 5 - 10 layers ○ If young leaf grows and of cellulose microfibrils. elongates, it must be supported by collenchyma and 2) Collenchyma (CC) as it matures, it will turn into Collenchyma cells - primary walls sclerenchyma (providing remain thin in some areas, but some elastic support that supports thickened (corners). leaf shape) Walls of collenchyma exhibits Support plant by strength alone; if plasticity (ability to deformed by withers, it remains upright. pressure and retain shaped even if PC and CC absorbs water - swell, pressure ceases) stretch walls, and growing; SC - Present in elongating shoot tips that strong to prevent the protoplast (cell must be long and flexible; present as w/o cell wall) from expanding. layers under the epidermis located Two types: conducting sclerenchyma next to vascular bundles (tips is and mechanical sclerenchyma stronger and break-resitant; can still elongate) 2 BOTANY [BIO421] Prelim Period ○ Mechanical sclerenchyma - is External Organization of Stems subdivided into long fibers and short sclereids ○ Both types have elastic secondary walls ○ Scelereids - short and more and less isodiametric (cuboidal); have strong walls oriented in all three dimensions; through this, sclerenchyma cells is form (brittle and inflexible) Stem and Shoot are used ○ Masses of sclereids form hard, interchangeably; Stem - axis and shoot impenetrable surfaces (e. - stem + leaves, flowers, buds. shells) When strength/resistance is the only All flowering parts have: selective of advantage of - Stem (nodes, internodes, leaf sclerenchyma, the protoplast dies after axil) deposited. - Within it, it contains axillary Living sclerenchyma cells are involved bud (either vegetative or in storing starch or crystals of calcium reproductive); covered by bud oxalate. scales (modified leaves) Sclereids and fibers develop from cells - Extreme tip is the terminal produced by cell division bud. Phyllotaxy = arrangement of leaves on stem; important to avoid shading others. - If only one leaf is present at each node, alternative phyllotaxy; if two leaves per node, opposite phyllotaxy; if three or more, it is whorled - Distichous Phyllotaxy - leaves are arranged in only two (di-) rows (-stichies) - Decussate Phyllotaxy - arrange in four rows - Spiral Phyllotaxy - leaf is located slightly to the form of spiral; most common 3 BOTANY [BIO421] Prelim Period Vines - internodes are especially long (used to explore); lettuce, cabbage, and onion - internodes are short (packed together) 1) Epidermis - Internodes can be wide, Outermost layer of intermediate, and narrow; this herbaceous plant provide adaptive advantages Single layer of parenchyma in certain situations cells; thin walls Stolons - greater capacity to explore; Absorption and expel of runners things happens in the - Internodes are long and thin; epidermis leaves do not expand Critical function: Bulbs - short shooters that have thick ○ preventing water loss fleshy leaves. to air Corms - vertical, thick stems, papery ○ Act as barrier against leaves invasion of bacteria Rhizomes - fleshy horizontal stems; ○ Shield delicate allow to spread underground internal cells Tubers - horizontal like rhizomes but ○ Reflectivity saves from grow for short period; means of storing overheating from nutrients; used informally for bulky sunlight underground plant organ Cutin - outermost tangential wall Dormancy - means by which perennial encrusted with it; fatty substance that plants of harsh climates survive the makes water impermeable. stress. Cuticle - cutin builds up more or less - Trunk = main shoot pure layer (in most plants); sometimes, - If the apical meristems are cuticle is not sufficient and a layer of healthy and growing well, wax may be present outside it some axillary buds are Cutin and wax resist digestive enzyme unneeded; if it is killed, axillary and provide defense against buds become active and pathogens; replace it (allowing growth to ○ Cuticle = smooth that fungal continue) spores cannot even stick and can be washed off. ○ Waxes = indigestible and Internal Organization of Stems non-nutritious ○ Both also inhibits carbon To function properly, tissues of an organ must dioixde needed for be arranged correctly. 4 BOTANY [BIO421] Prelim Period photosynthesis; this leads to 3) Vascular tissue plant starvation Every small organisms (unicellular or Epidermis contains guard cells (pair) thin sheets of cells), diffusion is w/ stomatal pore (hole) - constitute of adequate for the distribution of sugars, stoma (pl. stomata); stomatal pores minerals, etc. But if organism is opens at daytime permitting carbon separated from environmental dioxide. nutrients for days, diffusion is too slow ○ Made possible because of and the vascular system necessary. guard cell; that is because of Types of Vascular Tissues: structure and walls have a a) Xylem - Conducts water and minerals special radial arrangement of b) Phloem - Distribute sugar and cellulose microfibrils. minerals Trichomes - epidermal cells that Vascular system of plants is not elongate outward; also called hairs; circulatory. exist in hundreds of shape, size, and ○ Through xylem, water and narrow cells; unicellular mineral go upward to leaves ○ Makes it difficult for animals to and stem. Xylem saps travel land through hollow and dead ○ Shades underlying tissues by cells. Once in the shoot, most blocking sunlight which may water evaporates from the be too intense surface of leaves and flowers, ○ Create layer of immobile air and it’s lost, while the next to leaf surface to allow minerals are used by the water molecules to diffuse out surrounding cells. of stoma to bounce in back. ○ Phloem cells are living; pick up ○ Mostly die after maturity and sugar from areas where it is acts as protection; other abundant and transport it remain alive and acts as where sugar is needed. In the secretory glands. later months, phloem carries ○ Some secretes excess salt, sugar into developing fruits antiherbivore compounds, and and into the storage organs of digestive enzyme to trap perennial plants. insect (carnivorous plants) ○ Sugar must be dissolve to be conducted; water is 2) Cortex simultaneously transported in Interior to the epidermis phloem. For plants, simple, homogenous, has photosynthetic parenchyma, and I. Xylem sometimes collenchyma Two types of conducting cells: For other, it is complex and contain Tracheids and vessel specialized cell that secrete something elements. (mucilage, resin, etc. ) Both conducting cells are Cortex cells fit together compactly for types of sclerenchyma. most plants; others, in fleshy stems Tracheary elements - either (tubers), cortex parenchyma is type of cell. aerenchyma (large tissues w/ ○ As young cells mature intercellular air spaces used for into tracheary bouyancy) elements, they must first enter cell cycle 5 BOTANY [BIO421] Prelim Period arrest and stop Circular bordered pits - most dividing. derived and strongest ○ It is initially a small tracheary elements; virtually parenchyma cell w/ all primary wall is underlain only a thin primary by secondary walls. wall, but the cell ○ The pits that allow becomes long and water movement are narrow and then weak points in the deposit secondary wall, but the wall that weakness is reduced reinforces/strengthen by the border of extra the primary wall. wall material around ○ The secondary wall is the pit. impermeable to water; Pitted tracheary elements - thus, areas of the extremely strong; much of the permeable primary surface is underlain by wall must remain lignified (became rigid and uncovered if the water woody because of deposition is to enter and leave lignin) secondary wall that the cell. water enters/leaves slowly. Cell wall thickening happens Under dry conditions, using due to deposition of secondary extra glucose to build stronger wall substances. secondary walls can be a Annular Thickening - small valuable investment. amount of secondary wall Tracheids - obtain water from present, organized as a set of other tracheids below them rings, on the interior face of and pass above; must occur in the primary wall. groups, lying side by side and ○ Provides large surface overlapping; pits of adjacent for water movement, tracheids are aligned so that but doesn't provide water can pass through. much strength, hence, ○ Pit membrane - part primary wall must be of an aligned set of supported. pits (pit-pair) and Helical Thickening - the between the set of secondary wall exists as one primary walls and to three helices (coil) interior to middle lamella. the primary wall. Water Scalariform Thickening - permeable provides more strength since Set of primary the secondary wall underlies walls most of the inner surface of Has slight the primary wall; fairly resistance extensive; ladder-like Vessel elements - provides Pit - area where secondary way to water movement w/ wall is absent less friction than tracheids. Reticulate thickening - the ○ Individual cells secondary walls are deposited produce primary and in the shape of net. secondary walls 6 BOTANY [BIO421] Prelim Period before they die at maturity. ○ However, an entire region of both primary and secondary wall is missing. Perforation - large hole at final stages of differentiation; digested through a particular site of the primary wall, often removing the entire end wall. ○ At adjacent, must be aligned and each element must have at least two perforations (one on each end) II. Phloem ○ Water passes through Two conducting cells: Sieve this to go to form one cells and sieve tube members vessel element (both are sieve elements) Vessel - entire stack of vessel Different form of tracheary elements; can be a meter long elements; parechyma cells ○ The vessel elements (only primary walls) and must on each end of a remain alive. vessel have only one Sieve pores - happens when perforation. immature sieve elements ○ Must absorb water begin to differentiate and from parenchyma cell, plasmodesmata enlarge tracheids, or other (occurs in group); occur in vessels and must pass cluster called sieve areas it on. Sieve element remains alive ○ Greatly reduce friction during differentiation (process and water movement of taking up permanent form) is much easier. The two types of Sieve Tracheid and Vessels elements differ in shape and elements have placement of sieve areas. plasmodesmata in their ○ If elongate, spindle primary cells. shaped, and sieve Water molecules must move areas distributed all across the pit membrane if over surface, it is sieve entering or leaving tracheid or cell. vessel elements. ○ Sieve cell - found in older fossils and nonangiosperm. Sieve tube - If stacked end to end w/ their large sieve areas aligned. ○ Sieve plates - end-wall sieve areas w/ large sieve pores 7 BOTANY [BIO421] Prelim Period ○ Shorter than the plant ○ Sieve tube members - evolved at some time as the flower and can be found in angiosperms. Albuminous cells - associated w/ sieve cells Companion cells - controls the sieve tube members Both of the mentioned cells are smaller than conducting cells and have prominent Stem Growth and Differentiation nuclei, dense cytoplasm, and ribosomes. Apical Meristem - region where stem grow longer by creating new cells at 4) Vascular Bundle their tip; made possible because of Site where xylem and phloem occur mitosis and cytokinesis; also produces together; located at the interior of progenitor cells for the stem. cortex. Subapical Meristem - region below the In basal angiosperms and eudicots, apical meristem; divides and grow to these are arranged in one ring produce cells for the region below. surrounding the pith (region of ○ In the subapical meristem, parenchyma similar to cortex) visible differentiation occurs. In monocots, it is distributed as Certain cells stop dividing, complex network throughout the inner start elongating, and starts part of the stem; between the bundles differentiating into first are parenchyma cells; monocot tracheid/ vessel elements. bundles = scattered and presumed to ○ Protoxylem - constitutes the occur at random first xylem. All vascular bundles are collateral; ○ Metaxylem - cells that has the each contains xylem and phloem longest time for growth before strands parallel to each other. differentiation, they develop Primary Xylem - xylem of vascular into larger tracheary elements. bundles that is part of the primary ○ Protophloem - exterior mature plant body. cells that occurs in the outer ○ Usually a large proportion of part of vascular bundle. xylem parenchyma and ○ Metaphloem - cells closest to mechanical sclerenchyma in the metaxylem. the form of xylem. Sieve elements do not have secondary Primary Phloem - phloem of vascular walls. bundles that is mixed w/ sieve ○ Protophloem and metaphloem elements and albuminous/companion are identical; cells. ○ Protophloem - extremely ○ Storage of parenchyma and short-live; functions one day. mechanical sclerenchyma. ○ Metaphloem - do not Cells of the primary xylem are lapang. differentiate until later when all surrounding cells have stopped expanding. 8 BOTANY [BIO421] Prelim Period In the epidermis, the first stage of trichome outgrowth may be visible in the youngest internodes; closest to the apical meristems In the lower or older internodes, trichomes are more mature, and guard cells and stomatal pores may be forming. Cuticle is extremely thin at the apical meristems, but it is thicker in the subapical region and maybe complete several internodes below the shoot apex. Protoxylem and protophloem develop quickly while the cells are still close to the apical meristems, but metaxylem and metaphloem do not begin to differentiate until the nodes and internodes have stopped elongating. Protoderm - epidermal cells that are in the early stages of differentiation. Provascular tissues - young cells of xylem and phloem Ground meristems - equivalent stage of pith and cortex In stems w/ long internodes, maturation is slow and immature tissues can be found far below apical meristems. In stem w/ short internodes, differentiation may be completed quickly and all tissues are mature close to the stem apex. Summary Primary Tissue - tissues produced by apical meristems Primary growth - growth and tissue formation that results from apical meristem activity Secondary Tissue - produced by different type of meristems. 9 BOTANY [BIO421] Prelim Period Chapter 7 - Leaves ○ Long. thin, flexible petioles allow the blade to flutter in the wind; hence, it brings Introduction fresh air to its surface and a cooling effect to the leaf. This also makes it Leaves (Foliage Leaves - set of difficult for insects to leaves) - large, flat, green structures land on leaves. involved in photosynthesis. ○ If the leaf and air are still. Natural selection leads to leaves into Carbon dioxide is absorbed selectively advantageous: from the vicinity of the leaf ○ Bud scales/spines (protection) faster - depleting the carbon ○ Tendrils (support) dioxide and decreasing ○ Fleshy leaves of the bulb photosynthesis. (storage) ○ If leaves are small, very long, ○ Trapping and Digesting narrow, and have no petiole, insects (nitrogen then it is a sessile leaf instead procurement) of petiolate (stalks) ○ Sheathing Leaf Base - formed External Structure of Foliage Leaves when foliage leaves (monocot) tends to be very Foliage leaves functions: long and tapered and ○ Photosynthesis (Absorbs self-shading - leaf base wrap carbon dioxide and converts it around the stem - occurs (at into carbohydrates [glucose] the base) by using light energy) Blade is exposed to ○ Water retention sunlight. ○ Barrier against entry of fungi, Also doesn’t have bacteria, algae, etc. petiole ○ Avoids being a liability to the plant. 2) Type of Leaf Blade Either simple or compound 1) Leaf Blade/Lamina Simple leaf - one part blade Flaty, light-harvesting portion ○ Has photosynthetic cell Dorsal Surface/Abaxial Side - blade’s Compound leaf - blade divided into lower side; larger veins serve several individual parts backbones ○ Has many leaflets, which is Ventral Surface/Adaxial Side - blade’s attached to Petitolule to an upper side; usually smooth extension of petiole, rachis. Petiole/Stalk - holds the blade out ○ Usually, plants that grow in into the light the streams achieve this leaf ○ Prevent shading other plants w/ threadlike leaflets. 10 BOTANY [BIO421] Prelim Period ○ Has a great deal of 3) Veins nonphotosynthetic rachis, Within leaf and bundles of vascular petiolules, and edges. tissue. Distribute water from the stem into the leaf and simultaneously collect sugar made through photosynthesis and carry it to the stem for use or storage. Reticulate Venation - found in basal angiosperms and eudicots; they occur in a netted pattern. Advantages of Compound Leaf: ○ Flow turbulently when a mild breeze flows. The turbulence reduces the excess heat and brings in carbon dioxide. ○ Edges of the petiolule of a leaflet act as a barrier or slow the movement of the insects. ○ Abscises and carries the pathogen as it falls off when it damages a leaf; this helps to keep the leaf healthy. Parallel Venation - found in monocots Leaflets of a compound leaf are w/ long, strap-shaped leaves; the always arranged in two rows larger veins run side by side w/ few (distichous phyllotaxy). obvious interconnections. Other species produce two types of leaves simultaneously; one type on long shoots and one on short spur shoots. ○ e.g. Cacti - spine as short-shoot leaves, long-shoot leaves the green, fleshy, in most species are microscopic Leaf shape is valuable for plant identification. 11 BOTANY [BIO421] Prelim Period ○ Providing some shade on the upper surface of the leaf. Internal Structure of Foliage Leaves ○ On the lower surface, preventing rapid air 1) Epidermis movement and slowing water Flat, thin foliage leaves (optimal for loss from stomata. light interception) have a large surface ○ Secreting powerful stinging area through which water can be lost. compounds to avoid being Transpiration - water loss through the eaten. epidermis. Leaf epidermal cells contain cutin and Must be reasonably waterproof, wax on the outer walls. simultaneously translucent, and must ○ Retain water and make allow entry of carbon dioxide. digestion by fungi difficult. Also consists of flat, tabular (shaped ○ Prevent spores from sticking. like paving stones), ordinary epidermal cells, guard cells, and 2) Mesophyll trichomes (similar to stem) Ground tissues interior to the leaf The dorsiventral nature (dissimilar epidermis. dorsal and ventral surfaces) causes Palisade Parenchyma / Palisade the upper and lower epidermis to Mesophyll - main photosynthetic exist in significantly different tissue; layer along the upper surface microclimates. of leaves. ○ E.g. Sunny day = leaf is ○ Often one layer thick, but warmer, convection current three or four layers thick in rises from it, and water regions w/ intense sunlight. molecules are swept away by Spongy Mesophyll - in the lower this convection; however, air portion of the leaf; an open, loose tends to be trapped on the aerenchyma that permits carbon underside of leaf, so water dioxide to diffuse rapidly away from loss from stomata there is not stomata into the leaf. so great. Palisade Parenchyma is along leaf ○ No. of Stomata per square cm surface; spongy mesophyll occur in > Lower Side (Dorsal Surface) the center or lacking. ○ No. of Stomata per square cm < Upper Side; sometimes none at all. Leaf stomata are frequently sunken into epidermal cavities that create a small region of nonmoving air. Leaf epidermis are remarkably hairy, and trichomes affect leaf biology through: 12 BOTANY [BIO421] Prelim Period 4) Petiole Part of leaf and transition between stem and lamina. Petiole Mesophyll - like cortex and has a considerable presence of collenchyma if it supports a heavy lamina. Leaf Traces - vascular bundles that branch from stem vascular bundles and diverge toward the petiole. Stipules - two small flaps of tissue or leaf-life structure at the base. 3) Vascular Tissue ○ Protect apical meristems Between palisade parenchyma and while the leaf is young. spongy mesophyll. Eudicot leaf has midrib/midvein where Initial and Development of Leaves lateral veins emerge and narrow minor veins branch from. Basal Angiosperms and Leaves Eudicots Minor vein - releasing water from Leaves are produced through apical xylem and sugar from phloem; site for meristem. material exchange. Leaf Primordium - at the base of the Midrib and Lateral - involved in meristem where protoderm (root conduction; contain primary xylem apical meristem) grows outward - (upper side) and primary phloem forming protrusion and extending (lower side) upward taller-than-shoot apical Bundle Sheath - fibers arranged as a meristem. sheath around vascular tissues; make ○ Consists of leaf protoderm it difficult for insects to chew. and leaf ground meristem. Bundle Sheath Extension - a mass of As it grows upward, it establishes a fibers above, below, or both. midrib and initiates lamina - resulting ○ Give rigidity to the blade. in a young leaf consisting of a midrib and two small, thin wings. ○ All cells are meristematic, and their division and expansion enlarge the lamina rapidly. During lamina expansion, stomata, trichomes, and Initiation and vascular bundles differentiate, and the petiole becomes distinct from the midrib. In perennial plants, as they reach a developmental state, they became 13 BOTANY [BIO421] Prelim Period dormant - part of resting terminal or Reduction in surface area reduces the axillary buds. capacity for CO2. In the following growth period, the Exposed leaf tips allow sufficient light bud opens, and the leaves expand to to enter and be conducted to the absorb water for its vacoules. subterranean chlorenchyma. Monocots 2) Sclerophyllous Foliage Leaves Leaves are also initiated by the These leaves are feasible, and their expansion of shoot apical meristem hardness makes them more resistant cells to form leaf primordium. to animal and ultraviolet light. Apical meristem cells grow upward Plants = Sclerophyllous along with it, becoming part of the Leaves = Sclerophylls primordium and giving it a hoodlike Sclerenchyma is present as a layer shape. just below the epidermis (composed The tubular portion grows upward as of thick-walled cells) and in the a sheathing leaf base, and the original bundle sheaths, conical leaf primordium, now located ○ The cuticle is usually very on one side of the top of the tube, thick, and waxes are gives rise to the lamina. abundant on the leaves of ○ Outer surface of the tube = many sclerophyllous species. Abaxial Epidermis ○ Inner surface of the tube = 3) Leaves of Conifers Adaxial Epidermis Conifer leaves contain unpalatable The shoot apex enlarges, forms new chemicals. stem tissue and initiates the next leaf Simple, never compound, and has few primordium. forms After the first leaf, the next leaf Needles occur in all pines, firs, and elongates and emerges. spruces. The constant basal expansion in Mostly perennial, remaining on the monocot leaves means that the stem for many years, and plants are protoxylem and protophloem are evergreens. constantly stretched. 4) Bud Scales In perennial plants, dormant shoot Morphology and Anatomy of Other Leaf Types apical meristems are protected from low temperatures and the drying action of wind during winter by bud 1) Succulent Leaves scales, which form a tight layer Found in families Crassulaceae, around the stem tip. Portulacaaceae, and Aizoaceae Small and rarely compound, so Thick, fleshy, and favors water mechanical wind damage is not a risk conservation for bud scales. 14 BOTANY [BIO421] Prelim Period Must remain to the stem. Hence, the When an insect walks across the trap, petiole is either short or absent. it brushes against trigger hairs. If two Must be tougher and waxier than of these are stimulated, midrib motor regular leaves. cells lose water quickly, and the trap rapidly closes as the two halves of the 5) Spines lamina move upward. Cacti have two types of leaves. ○ After digestion and Green cactus body - microscopic absorption are complete, the green leaves and clusters of spines midrib motor cells fill with that serve as axillary buds (modified water, swell, and force the leaves of axillary buds) trap open, ready for a new Moist succulent body - succulent; victim excellent source of water. No blade and are needle shaped. 6) Tendrils Grow indefinitely and contain cells capable of sensing contact with an object. If it touches something, the side facing the object stops growing, but the other side continues to elongate. ○ This causes the tendril to coil around the object and use it for support. 7) Leaves with Kranz Anatomy Occurs in plants that have a special metabolism called C4 photosynthesis. Lack palisade parenchyma and spongy mesophyll but have prominent bundle sheaths composed of large chlorophyllous cells. 8) Insect Traps Ability to trap and digest insects. Either active traps (move during capture) or passive traps (incapable of movement) Thin, parenchymatous, and capable of photosynthesis. Lamina is tubular rather than flat, and it secretes a watery digestive fluid. 15