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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bitki’de genel görünüş.

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Presentation on theme: "Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bitki’de genel görünüş."— Presentation transcript:

1 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bitki’de genel görünüş

2 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bitkilerde hayvanlarda olduğu gibi organ, doku, hücre hiyerarşisine sahip Root sistem ve shoot sistem Üç basic organ; kök (root), gövde, yaprak Figure 35.2 Reproductive shoot (flower) Terminal bud Node Internode Terminal bud Vegetative shoot Blade Petiole Stem Leaf Taproot Lateral roots Root system Shoot system Axillary bud

3 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Root (kök) – Ortama bağlar – Mineral ve su absorbe eder – Organik madde depo eder – Gravitropism – Absorbsiyon tip (uç) kısma yakın yerde olur (çok sayıda ince türler, yüzey artırır) – Lateral kök ve emici tüyler aynı mı? – Kazık ve saçak kök

4 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Embryonic root veya radicle

5 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Tap (kazık) root ve Fibrous (açak) kök Her iki tipte radicle’den orjin alır

6 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

7 Adventitious Roots: Radicle’den başka yerde orjin alan kök

8 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Modifiye kök (a) Prop roots(b) Storage roots (c) “Strangling” aerial roots (d) Buttress roots (e) Pneumatophores (f) Photosynthetic roots (f) Contractile roots

9 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Dış Anatomi Root cap (Kök şapkası) Hücre bölünme bölgesi Uzama bölgesi Farklılaşma bölgesi

10 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Root Cap (Kök şapkası) Her bir kök ucunda yüksük şeklinde olan hücre grubu Mekanik yaralanmaya karşı kök’ü korur Golgi mükilaj salgılar ve labirent oluşturur Yer çekiminin algısında etkili – Amyloplastlar (statolit) hücrenin alt kısımlarında gruplaşmış

11 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hücre bölünme bölgesi Apical meristem - gün içinde bir veya iki defa bölünür Meristem : – protoderm (epidermis oluşturur) – ground meristem (zemin dokuyu verir) – prokambium (primary phloem ve xylem)

12 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Uzama bölgesi Hücreler daha uzun ve geniş

13 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Farklılaşma bölgesi epidermal hücrelerin uzantısı olarak emici tüyler oluşur Su alımı için yüzey artırıcı Kütikül kökte vardır ama emici tüylerde yok

14 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Farklılaşma bölgesi

15 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lateral kök Pericycle’dan köken alır Figure Cortex Vascular cylinder Epidermis Lateral root 100  m Emerging lateral root

16 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Root Cap Bülünme Böl. Koteks dışına doğru büyüme Saçaklı (Fibrous) kök, çok sayıda lateral kök oluşumu

17 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Kök nodülü ve Azot fiksasyonu Atmosferde serbest azot Bakteri (Rhizobium, Clostridium) Anabaena, Nostoc Mycorrhiza Kök nodülü Azot fiksasyonu

18 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Mikoriza Mantar Bitki ilişkisi Ekto ve Endo Arbüskül Fosfor, şeker

19 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hetetrof bitkiler Parazit Genelde Fotosentez yok Hemiparazit: klorofil var, su minerali konakçıdan alır, stomalı yaprak, kök toprakta değil konakçı epidermisinde Holoparazit: klorofil yok, enerji konakçıdan alınan glikoz, yaprak yok yada indirgenmiş,

20 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hostorium (Emeç) kök Parazit Kök sisteminde değişim olur Ksilem bağlantılı, Fotosentez yapar Ksilem ve floem bağlantılı

21 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Uyarılara verilen tepkiler Tropism – Foto- – Gravi- – Kemo- (polen tüpü olusumu) – Tigmo-

22 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Tropism (tropizma) Uyarana dogru (+) veya ters (-) yönelim Fototropism – en iyi bilinen hareket- ısığa yönelim. Gölgede kalan hücrelerin uzaması veya üremesi. Bükülme (Curving) hormone auxin - auxin migrates to the shaded part of the plant and stimulates increased cell growth and elongation on the shaded part of the plant

23 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Fototropism Phototropism is the growth of stems of plants toward light - it is probably the best known of the plant tropisms - phototropism is caused by elongation of the cells on the shaded part of the plant - so that entire plant bends or curves toward the light This growth pattern is caused by the hormone auxin - auxin migrates to the shaded part of the plant and stimulates increased cell growth and elongation on the shaded part of the plant

24 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

25 Tropisms: cell elongation In general, tropisms involve cell elongation or suppression of cell elongation on one side of a plant, causing the plant to grow in a particular direction.

26 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Auxin Acts by loosening cellulose microfibrils of cell walls Causes cell expansion

27 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gravitropism root will curve to grow downward the shoot will curve to grow upward –Auxin –Calcium ( calcium moves to upper surfaces of shoot cells before the shoot actually curves upward and calcium moves to bottom surfaces of root cells before the root actually curves downward) –Amyloplast (root cap of roots)

28 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gravitropism in shoots In shoots, auxins are more concentrated on the lower side of the stem, causing the cells there to elongate.

29 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gravitropism in roots In roots, however, auxin concentration on the lower side of the root suppresses cell elongation. The upper side of the root continues to grow, causing the roots to bend downward.

30 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Plastids and Gravitropism How does a root “know” which way is down? Plastids, particularly leucoplasts, in the root cap cell tend to settle on the bottom side of the cell. This stimulates the release of auxins.

31 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

32 Gravitropism in plants

33 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

34 Tigmotropism touch or contact with a solid object this is most commonly seen in tendrils (modified leaves or stems depending on the species) the response can be rapid, a tendril can wrap around a support one or more times in less than an hour

35 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

36 Kirkadian Rhythms Gün içinde belirli zamanlarda olan hareket some plants open their leaves at dawn and shut them at dusk - some plants may open and shut flowers as the day changes from dawn to dusk Photosynthesis, auxin production, and the rate of cell division all have regular daily rhythms adjustments of growth, reproduction, and other activities of the organism

37 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Plant Growth Regulator

38 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Plant Growth Regulators Biyokimyasal reak. aktive eder Plant hormones or plant growth regulators are rather different from animal hormones in chemical structure, mode of synthesis, and function. Higher animals possess glands that are part of their endocrine system that are specialized organs for production of hormones Plant hormones on the other hand are synthesized in the cells of general organs – the stems, leaves, roots, and flowers

39 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Plant Hormones Plant hormones can be divided into two classes: – Growth promoters: Auxins, Gibberellins, Cytokinins – Growth inhibitors: Ethylene gas, Abscisic acid

40 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Growth promoters Hormones can promote plant growth in two ways: – Stimulating cell division in meristems to produce new cells. – Stimulating elongation in cells.

41 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Auxin activity Auxins stimulate genes in cells associated with plant growth.

42 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Auxin roles Auxins carry out multiple roles having to do with plant growth including: – Tropisms – Apical dominance – Growth of adventitious roots – Fruit growth

43 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Auxin = Indole Acetic Acid (IAA) 1)Functions in phototropism = movement toward light - Auxin concentrated on dark side - Induces cell expansion / elongation

44 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Apical dominance Auxins are released from the shoot tip. These stimulate cell elongation in the stem, but suppress the lateral buds. Cytokinins, produced in the roots, can stimulate lateral buds if the shoot tip is removed.

45 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Auxin apical dominance Auxins produced by apical meristem Inhibits growth of lateral branches If apical meristem damaged, auxin production stops No longer inhibits lateral branch growth lateral buds ---> branches

46 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Adventitious roots Adventitious roots are those growing out of places where roots don’t normally grow. Auxins stimulate root growth on the end of a houseplant cutting..

47 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Fruit growth Developing seeds produce auxins that stimulate growth of the plant ovary into a fruit. Removal of seeds from a strawberry prevents the fruit from growing, but add auxin and will grow. How could this be used in commercial agriculture?

48 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gibberellins 1) Function in seed germination - Embryo releases gibberellins - Causes aleurone layer (in seed coat) to release enzymes (alpha-amylase): break down starch in endosperm to sugars (e.g., maltose) E.g., germinatio n of barley (beer production)

49 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gibberellins 2) Fruit development Seedless fruit crops (e.g., grapes) may be artificially sprayed with gibberellins - make fruits bigger

50 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Gibberellins 3) Stem growth (elongation, longer internode) gibberellins added

51 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Functions of Cytokinins Promote growth of lateral buds when auxin concentrations are low. Promote cell division in meristems. Stimulate fruit and seed development. Delays senescence of plant parts.

52 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Functions of Ethylene Released by fruits and causes the fruits to ripen faster. Causes plant parts to age and die (senescence). Inhibits stem elongation.

53 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Which of these methods will make your tomatoes ripen faster and why? – Putting them on a sunny windowsill. – Putting them in a paper bag. WORKTOGETHERWORKTOGETHER

54 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Functions of Abscisic Acid Controls seed and bud dormancy. Inhibits gibberellins. Promotes senescence in plants.


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