Crop Sci Final Reviewer PDF

CHAPTER 2: BIOLOGY OF AGRICULTURAL CROPS PARTS UNIQUE TO PLANTS: A. CLASSIFICATION & TAXONOMY OF CROPS Purpose: order, organization, and logical naming Plastid Doubl...

CHAPTER 2: BIOLOGY OF AGRICULTURAL CROPS PARTS UNIQUE TO PLANTS: A. CLASSIFICATION & TAXONOMY OF CROPS Purpose: order, organization, and logical naming Plastid Double membrane bound; contains Bases: Aristotle – by structure and size; own DNA & ribosomes. Linnaeus – by structure only; Proplastid Precursor to other plastid types Modern classification – by Phylogeny. Chromoplast Non-photosynthetic, colored BOTANICAL SYSTEM – by taxonomic categories Amyloplast Colorless, starch-storing AGRONOMIC SYSTEM – cereals, legumes & pulses, root crops, annual Etioplast Under-developed chloroplast fiber crops, special purpose crops, pasture or forage crops & industrial Chloroplast Site of photosynthesis crops. vacuole Large, central cavity for storage HORTICULTURAL CLASSIFICATION – Vegetables, fruit crops, plantation crops, ornamental crops. PLANT TISSUE SYSTEM: OTHER CLASSIFICATION – o Meristematic tissue GROWTH HABITAT LEAF RETENTION LIFE-SPAN  Apical ( up/down growth) Vine Terrestrial Evergreen Annual  Lateral ( side growth) Shrub Mesophyte deciduous Biennal  Intercalary (between internodes) Tree Xerophyte perennial o Permanent tissue o Simple tissue herb Aquatic  Parenchyma (seat of activity) Epiphyte  Collenchyma (support) Halophyte  Sclerenchyma (lignified) Sciophyte  Fibers parasite  Sclereid o Complex tissue  Phloem BASED ON AGRICULTURAL PURPOSE:  Xylem  Cash – added income PARTS OF THE PLANT BODY:  Green manure – for nitrogen Shoots – above ground structures, central axis w/ appendages.  Cover – against erosion Roots – below ground structures.  Dye and tannin – for the same  Hedge – grown under main crop Characteristic DICOT MONOCOT  Biocidal – to control pests Leaves Broad Narrow  Trap – attract pests Leaf venation Netted Parallel  Repellant – repels pests and pathogen Leaf sheath None Containing  Attractant – attract natural enemies for control Branching Bushy Single stem w/ tiller B. NATURE AND COMPOSITION OF PLANTS Stem Woody Herbaceous Flower part Multiple of 4 or 5 Multiple of 3 NATURE – A plant body is made of organs w/c are made of tissues Mature root system Primary, adventitious, both adventitious then cells followed by organelles w/c are composed of molecules w/c are finally made of elements GENERAL ANATOMICAL REGIONS: ORGANELLES & OTHER COMPONENTS: o Epidermis – outermost layer ORGANELLE FUNCTIONS o Cortex – next to epidermis o Pericycle – found in root branches cell wall Cell support and regulation o Vascular bundle – phloem & xylem Middle lamella Outermost layer; made of PP o Pith – hollowe part in stem centers Primary wall Made during active growth Secondary wall For support, made of lignin & cellulose ANATOMICAL REGIONS OF LEAF: Cell membrane Cell boundary; semi-permeable 1. EPIDERMIS – skin of plants; covered in cuticle &has openings Nucleus Contains DNA called stomates (stomata). Cytoplasm Cell matrix where structures are embedded 2. MESOPHYLL – cells w/ plastids especially chloroplast Mitochondrion Cell powerhouse 3. VASCULAR BUNDLE – xylem and phloem Ribosomes Site of protein synthesis VASCULAR VESSELS: Endoplasmic reticulum Lipid and protein synthesis; transport & support Peroxisome Metabolizes photosynthetic waste o XYLEM – translocates water & mineral ions (from roots Glyoxisome Fat metabolism to the rest). o PHLOEM – translocates inorganic substances & sugars Golgi apparatus Processes and packages cell components (from stem to the rest). Microtubules Support, movement, and cell division plasmodesmata Cell bridges or tunnels LIGNIFICATION – the process in w/c lignin wax is beind laid down on the inside of cells causing death LIGNIN – complex carbo-polymer w/c makes 25% of trees.  o Plant propagule o Ornamental for pigment color o Modified leaf:  Bulbs – underground shoots with fleshy leaves and short stem FLOWER: Reproductive organ of plant; creates fruit; serves in sexual reproduction w/ seeds as final product. Produced by spermatophytes or flowering plants (seed plants). o GROUPS OF SPERMATOPHYTES: 1. Gymnosperms; older, more primitive; includes Conifers & cycadeans 2. Angiosperms – usually seen as original flowering plants, includes most species o PARTS OF A FLOWER  Perianth: calyx & corolla  Calyx: sepals (protects buds)  Corolla: petals (pollinator attractor)  Androecium: male reproductive organ (made up of stamens) MAIN COMPONENTS OF SHOOT SYSTEM:  Staminodes: sterile stamens o Stem  Gynoecium: female reproductive organ o Leaf (carpel & stigma) o Flower  Apocarpy/choricarpy: 1 carpel/pistil o Fruit ( contains the seed)  Coenocarpy: several carpel/pistil  Pistil: made up of enlarged ovary, style, stigma MORPHOLOGY OF ANDROECIUM & GYNOECIUM: STEM: 1. Hypogynous – the perianth is attached to the receptacle below the pistil MONOCOT DICOT 2. Perigynous – the perianth and stamens are borne on the rim of a concave structure in the depression of which the pistil is borne 3. Epigynous ovary – blossom seems to arise upon or above the ovary PLANT TYPE ACCORDING TO SEX: 1. Androgynous – w/ androecium and gynoecium e.g. papaya 2. Monoecious – both male & female live in same plant e.g. corn 3. Dioecious – male and female each on separate plan e.g. squash FLOWER TYPES: o COMPLETE – w/ sepal, petal, stamen, pistil in the same flower o INCOMPLETE – lacking any one or more parts (wind pollinated) o PERFECT/BISEXUAL – w/ both sex parts o IMPERFECT/UNISEXUAL – contains either stamen/pistil only  Staminate flowers: only stamen  Pistillate flowers: only pistil The STEM is needed for translocation (sugar, mineral & water), leaf FLOWER TYPES AFFECTING POLLINATION: support, to connect leaves with roots, and storage. o DICHOGAMOUS (organs mature at diff. time) Bud: embryonic stems  PROTANDROUS – stamens mature ahead of pistils Arrangement: alternate, opposite, whorled  PROTOGYNY – stigma becomes receptive before position: terminal, lateral, accessory, or adventitious stamens Nature of organs: leaf, flower of mixed o AUTOGAMOUS ( plants self pollinate in the same flower) structure & growth pattern: single upright/ prostrate branched  CHASMOGAMOUS – opens during pollination “creepers”  CLEISTOGAMOUS – closed during pollination MODIFIED STEMS: FRUIT: part of flowering plant; comes from specific flower tissues; used 1. Tendrils – support/attachment (climbing plants) in disseminating seeds; result of 1 or more flower maturation; gynoecium 2. Stem tendrils – opp. Side of stem forms all or part of the fruit. 3. Rhizome – enlarged stem for storage & reproduction. 4. Tuberous stem – same w/ rhizome but w/ bud eyes o True fruits – EUCARP; mature/ripe ovary after fertilization 5. Corm – vertically growning enlarged stem o False fruits – PSEUDO-CARP; from floral parts except ovary 6. Runners/stolon – slender branches growning horizontally/obliquely downwards MODES OF FRUIT DEVELOPMENT: 7. Phylloclades/cladodes – flattened/cylindrical green stems o Apocarpous fruits – from one flower w/ 1 or more sep. carpels 8. Offshoots – suckers – daughter plants from main 9. Bulbils – found in axil of leaves o Syncarpous fruits – from 1 gynoecium w/ 2 or more fused carpels LEAF: Principal Photosynthetic Organ o Multiple fruits – formed from many different flowers o Absorbs chemicals & micronutrients o Transpiration o Storage KINDS OF FRUITS 1. Simple (result of ripened simple/compound ovary w/ one pistil) A. Dry – not fleshy PART FUNCTION & CHARACTERISTIC Pod Developed ovary enclosing the seed Dehiscent capsular: Indehiscent achenial: Schizocarpic splitting: Embryo area Area of embryo axis w/c turns into the legume seed opens for seed Doesn’t open for seed splits into 2 or more Micropyle Point of entry of pollen tube into the ovule during discharge discharge closed, 1 seeded parts fertilization Legume – pea Caryopsis – wheat, rice Lomentum – mimosa, Hilum Point of attachment: seed to legume pod acacia Hypocotyl Stem tissue between the epicotyl & the radicle Follicle – (1 carpel) Cypsela – dandelion Cremocarp – coriander Radicle Embryonic root; develops into root central axis milkweed Epicotyl Embryonic shoot & leaves; contains apical meristem & 1st two unifoliolate leaves. Silique – radish, Nut – hazelnut, acorn, Regma – castor, Cotyledon Seed leaves and serve as food supply during cabbage, mustard cashew nut geranium germination & emergence Testa True seed coat of a legume seed; acts as protective Silicle – Sheperd’s Samara – elm Carcerulus – salvia tissue for the internal seed parts. purse FUNCTIONS OF ROOT SYSTEM: Capsule – brazil nut, Double/ compound 1. Anchorage &support cotton samara – Elm, maple 2. Absorption of nutrients & water B. Succulent - (part or all of pericarp is fleshy @ maturity; has 3. Plant propagules for some plants 3 different layers: pericarp, epicarp, mesocarp) 4.nitrogen fixation (legumes) Drupe Coconut, walnut 5. Storage of water & carbohydrates 6. Soil conservation Berry Simple fruit from 1 ovary Thin outer layer; not self-supporting TYPES OF ROOT SYSTEMS: true berries/ baccae Modified berries Pepo: papaya, banana o Fibrous – numerous, similar sizes, no primary root, shallow Hesperidium: citrus o Tap – one central primary root w/ several branches, deep Pome Apple, pear OTHER CLASSIFICATIONS: Balausta Pomegranate o Adventitious – arises from stem Amphisarca Dry, rigid; Baobab Tree o Storage, aquatic, brace, and aerial MODIFIED AND SPECIALIZED ROOTS 2. aggregate/etaerio (develops from 1 flower w/ many pistils or many carpels) e.g. raspberry, strawberry, rose, blackberry, o Buttress roots – large, found in nutrient poor forest, prevents soursop, guyabano) tree from falling over 3. Multiple/composite (1 formed from a cluster of flowers called o Tuberous roots – enlarged for storage (e.g. carrot, radish, inflorence) singkamas, sweet potato, lesser yam) o Syconus: hypothandium type e.g. fig o Prop or stilt roots – adventitious, helps support and anchor the o Sorosis: catkin, spike or spadix type e.g. pineapple, shrub, provides aeration jackfruit, mulberry  Lenticels – provide gas exchange and add. O2 source, highly hydrophobic Other related terms:  Pneumatophores/pneumatorhiza – located above o Parthenocarpy – fruit set w/o fertilization; may or may not water level require pollination  Aerenchyma tissues – projections allow gas exchange o Stenospermocarpy – seedlessness results from abortion of o Root nodules – root enlargement w/ nitrogen-fixing bacteria embryonic plant, requires pollination & fertilization (Rhizobium), root nodules develop because of symbiosis. o Seed dispersal – spread of seeds by other physical factors o Mycorrhiza – fungi & root symbiosis; plants provide the former with carbohydrates, while fungi provide water and minerals for SEEDS: miniature plants in arrested state the latter. MONOCOT SEED C. THE NATURE & COMPOSITION OF PLANTS PART FUNCTION & CHARACTERISTIC CONCEPTS RELATED TO PLANT GROWTH: brush Tuft of persistent hairs Dent Top of corn kernel; due to shrinking of inner starch o Leibig’s Law of the Minimum - states that yield is proportional Pericarp Primary ovary tissue; protects CARYOPSIS* to the amount of the most limiting nutrient, whichever nutrient Aleurone layer Outer few cell layers of endosperm: has enzyme for it may be (Barrel concept). breaking endosperm material o Blackman’s Theory of Optima & Limiting Factors – when the Endosperm Mostly starch; makes the bulk of the grain process is conditioned as to its rapidity by a number of separate starchy – soft, white factors, the rate of the process is limited by the slowest factor flinty – hard, vitreous (Linear response) endosperm proteins – source of protein in grains o Mitscherlich Law of Diminishing Returns – when plants have Scutellum Secretes enzymes for breaking down endosperm right amounts of all but one limiting element, the growth Coleoptile Apex of embryo axis; serves as protective sheath for response is proportional to the limiting element and tends to young leaves increase with every increments of a limiting factor though not Epicotyl Embryonic leaves and root in direct proportions (curvilinear response). Apical Above scutellar node, stalk and leaf tissue develops meristem here o Growth – irreversible increase in size, length & volume Scutellar node Point of attachment of scutellum to embryo axis o Development – change in size, shape, form, degree of Radicle Embryonic root differentiation, & state of complexity Coleorhiza Protective sheath surrounding the radicle o Differentiation – progressive change simple meristematic Black layer Indicates physiological maturity tissue to complex and variable tissue & tissue combinations in tip (Pedicel) Point of attachment: kernel to flower stalk adult plant bodies. *ripened ovary fruit but not a true seed PHASES OF PLANT GROWTH o water comes from the soil, CO2 goes through stomata o Site of Light reaction – Thylakoid (here light is transformed 1. LAG – early vegetative growth into chemical energy during w/c water is oxidized & 2. LOG – grand period of growth, rate is exponential reduced by NADPH & ATP is produced) 3. DECLINING – flowering onset is offset by leaf fall o Site of CO2 reduction – stroma 4. STEADY – grain filling & ripening occurs steadily until end o Reaction centers – photosystem I & II {ps II catalyzes 5. SENESCENCE – characterized by death of the plant and parts removal of e- from H2O molecules (photolysis – water STAGES OF PLANT DEVELOPMENT oxidation); ps I absorbs LE independently but its core component receives e- from H2O taken by ps II}. 1. SEEDLING – starts w/ germination until true leaves grow. 2. VEGETATIVE – juvenile stage between germination & flowering o Phases (w/ progressive development of root systems & foliage). Photophase Dark Phase 3. REPRODUCTIVE – occurs when plants start to flower until fruits = Light Phase = Enzymatic Phase & seeds mature = Light Reaction = Dark Reaction o Dormancy – seed’s inability to germinate due to Photolysis of Water : CO2 Fixation: certain factors = Splitting of water to = C3 (Calvin Cycle), C4 or CAM (Crassulacean o Quiescence – seed’s failure to germinate due to 2H+ + 2e- + ½O2 acid metabolism) Pathways absence of any req.’s for germination Photosystems II & I Cyclic Phosphorylation & o Germination – resumption of growth of the embryo causing the radicle to rupture the seed coat or by the Z-scheme, Hill Reaction Non-cyclic phosphorylation shoots leading to seedling emergence. In the THYLAKOIDS of In the STROMA of CHLOROPLAST CHLOROPLAST GERMINATION STAGES PATTERNS REQUISITES CONDITIONS A. LIGHT REACTIONS: Activation Epigeous – 1. Seed must WATER hypocotyl be viable a. antenna pigments elongates and chlorophyll a, b, B- raises cotyledon carotene & Zeaxanthin above ground (mostly dicot) serve as energy funnel Digestion& Hypogeous – 2. internal PROPER b. Z-scheme, Hill translocation hypocotyl conditions TEMPERATURE reaction doesn’t raise must be cotyledon above favorable ground; only epicotyl emerges NONCYCLIC PHOTOPHOSPHORYLATION: light reactions across thylakoid Cell division 3. seed must be OXYGEN where e—from water transfer to NADP+ accompanied by H+ transport embryo growth subjected to radicle or appropriate CYCLIC PHOTOPHOSPHORYLATION: e-- from PS I cycle back thru shoot emerges environmental ferrodoxin to some components of electron transport system causing ATP conditions formation by ATP synthase LIGHT IN SOME NADPH & ATP generated in light phase are reserved to be used in dark METHODS OF BREAKING DORMANCY: SPECIES (red phase. light) 1. Soaking in water (cold or warm) B. CO2 FIXATION 2. Scarification 3. Stratification – store seeds in high moisture & low temp. environment C3 pathway – 1st product: 3-PGA (phospoglyceric acid); 1st step: carboxylation (add CO2 & H2O to RuBP to form 2 molecules of 3- 4. Chemical Treatment – KNO3, thiourea, hydrogen peroxide, G regulators PGA (carboxylating enzyme: RuBP carboxylase)). 5. Breaking the seedcoat – removing hilum covering C4 pathway – 1st product: oxaloacetic acid; 1st step: METHODS OF TESTING SEED GERMINATION: carboxylation of PEP to form OAA; enzyme: PEP carboxylase Kranz anatomy – special type of cell org. in C4 plant leaves. 1. Ragdoll 3. Petri dish Method These are bundle sheath (BS) cells that surround the vascular 2. Seedbox method 4. Tetrazolium test* centres, and mesophyll (M) cells that, in turn, surround the BS cells. *a sol’n of 2,3,5 triphyenyltetrazolium chloride is added to water to form Crassulacean Acid Metabolism (CAM) – CAM plants grow in colorless sol’n. Seeds are placed in 1% sol’n (unbisected), or dilute 0.1% areas with little water; closes stomata by day, opens at night. sol’n for bisected grasses & cereals. Results are either: SOUND (normal Fixes atmospheric CO2 to make malic acid (stored in vacuole at red color shows while resisting penetration (H release is slow)); or WEAK night and defuses to cytosol where it is decarboxylated by day) LIVING (abnormal color meaning they’ve lost resistance. Respiration’s C3 vs. C4 plants – C4 plants maintain high ratio of CO2/O2 w/in accelerated, formazan forms rapidly, bruised* photosynthetic cells to minimize photorespiration Energy yield: 12 NADPH + 18 ATP + 6 CO2 (PHOTOPHASE) → CHAPTER 3: PHYSIOLOGICAL PROCESSES C6H12O6 + 12NADP+ + 18 ADP + 18 P + 6O2 Photorespiration - refers to a process in plant metabolism A. PHOTOSYNTHESIS (PS) where the enzyme RuBisCO oxygenates RuBP, causing some of o General Reaction: CO2 + H2O + light → CH2O + O2 the energy produced by photosynthesis to be wasted. o Crop yield depends on PS efficiency Factors affecting photosynthesis – light, CO2 concentration, o Photosynthetically active Radiation (PAR), wv of 380 nm leaf diffusive resistance, temperature, water, leaf age, mineral (violet) to 760 nm (red) in visible part of energy spectrum status. o Apparatus – chloroplast o Processes, products & sites: B. RESPIRATION Light Rxn + ← CO2 → O2 Movement of CO2 & O2 to & fro the outside (to cells) sucrose Calvin cycle PhotoPhos- Importance – generates NADH & ATP; produces CO2 skeleton sugar ← synthesis ← triose ←(in chloroplast- ← NADPH ← phorylation ← H2 O for compound synthesis (in cytosol) stroma) ← ATP ← (in chloroplast-