Biji dan Buah PDF

BIJI & BUAH Perkembangan, Struktur dan Fungsi  FERTILISASI Fertilisasi pada tumbuhan Angiospermae merupakan fertilisasi ganda Saat fertilisasi dan embriogenesis, peristiwa dalam kantung embrio : ▪ sel telur difertilisasi oleh satu sperma membentuk zigot yang dipl...

BIJI & BUAH Perkembangan, Struktur dan Fungsi  FERTILISASI Fertilisasi pada tumbuhan Angiospermae merupakan fertilisasi ganda Saat fertilisasi dan embriogenesis, peristiwa dalam kantung embrio : ▪ sel telur difertilisasi oleh satu sperma membentuk zigot yang diploid, zigot tumbuh menjadi embrio ◼ ▪ inti polar difertilisasi oleh inti sperma lainnya membentuk endosperm yang triploid atau poliploid ▪ Endosperm : jaringan nutrisi yg mengakumulasi pati, protein, dan lemak sebagai bahan makanan untuk pertumbuhan embrio ▪ Inti antipodal dan sinergid senesce and disintegrate  Struktur dan Fungsi Biji ▪ Dari Mana (Dari Jaringan Apa) Biji Berasal ? ▪ Bagaimana Struktur Biji ? ▪ Apa Fungsi Biji ?  Dari Mana (Dari Jaringan Apa) Biji Berasal ? ovulum = bakal biji ovarium = bakal buah Integumen – kulit biji  Post fertilization changes in ovary Ovary Develops into Fruit Ovary wall Pericarp Ovul Seed Funicle Stalk of seed Hilum Hilum Nucellus Perisperm Outer integument Testa Seed coat Inner Integument Tegmen Micropyle Micropyle Embryo Sac Synergids Degenerate Egg cell Embryo Antipodals Degenerate Secondary nucleus Endosperm Pembentukan Biji (EMBRIOGENESIS) 1. Mencakup perkembangan dari saat fertilisasi sampai fase dormansi 2. Pemantapan bentuk dasar tumbuhan ▪ Pola radial yang menghasilkan 3 sistem jaringan dan pola aksial yang menghasilkan pembentukan sumbu basal-apikal (pucuk – akar). ▪ Penyusunan jaringan meristematik untuk mengelaborasi struktur setelah Pola radial dan aksial masa embrio (daun, akar, bunga dsb.) embrio 3. Pemantapan penyimpanan cadangan (a) Pola radial pada makanan yang cukup untuk Angiospermae mulai perkecambahan embrio sampai pada saat stadium kecambah bersifat autotrof globular 4. Persiapan dormansi biji (b) Pola aksial (sumbu akar-pucuk) terbentuk saat stadium jantung  Pada tumbuhan, proses embriogenesis diakhiri dengan adanya dormansi Pembentukan organ vegetatif tumbuhan terjadi setelah perkecambahan Sistem organ reproduktif (bunga) berkembang dari pemrograman kembali meristem apeks pucuk setelah kecambah membentuk tumbuhan dewasa Embriogenesis pada hewan berlangsung mulai dari saat fertilisasi sampai bayi lahir  EMBRIOGENESIS Following fertilization of the egg cell by a sperm cell, the zygote develops inside the seed. Sequence of development proceeds through: Histodifferentiation ( = embryogenesis) is characterized by differentiation of the endosperm and embryo cell expansion and maturation & drying. Embryogenesis is similar but unique for monocots, dicots and gymnosperms  Current perpectives on the hormonal control of seed development in Arabidopsi and maize : a focus on auxin Brassinosteroids (BRs) DORMANSI ▪ Mempertahankan diri terhadap kondisi yang tidak sesuai (panas, dingin, kekeringan dll) ▪ Proses dormansi : ▪ desikasi – kehilangan air ▪ diferensiasi testa ▪ sintesis protein, transkripsi gen terhenti ▪ pengurangan laju respirasi dan proses metabolisme  Tahapan embriogenesis Pembelahan asimetris dari zigot menghasilkan embrio yang terdiri atas: bakal embrio - akan membentuk embrio dan suspensor Suspensor : i. melekatkan embrio (di dalam kantung embrio) ke jaringan ovulum ii. berfungsi untuk menyerap nutrisi dari jaringan induk (sporofit) ke embrio yang sedang berkembang iii. akan mengalami penuaan setelah embrio mencapai stadium jantung dan akhirnya merupakan bagian yang tak berfungsi setelah biji dewasa (matang) Diferensiasi organ embrionik dan jaringan yang ada di dalamnya terjadi selama masa transisi dari stadium globular ke stadium jantung  Monocot embryogenesis embryo structure in mature seed of monocots more complex than dicots, but their early embryo development is similar embryogenesis stages in monocots : proembryo, globular, scutellar and coleoptilar stages Following fertilization, the first cell division is a symmetrical and leads to an apical and basal cell The apical cell divides more rapidly and become the embryo globular Globular dicots Proembryo stage late globular stage In late globular stage: outer epidermal layer is evident and a group of cells on one side of the proembryo divides more rapidly. These will give rise to the embryo axis. Scutellar stage ▪ remnant of cotyledon can be seen in scutellar stage of development. ▪ Monocots have reduced the pair of cotyledons represented in dicot embryos to single modified cotyledon termed scutellum. ▪ scutellum acts as conductive tissue between endosperm and embryo axis. Scutellar stage Coleoptilar stage ▪ embryo axis differentiates in to plumule (shoot) and radicle. ▪ embryo axis also has a specialized tissue surrounding shoot and root tissue to aid in emergence during germination → coleoptile and coleorhiza, respectively Coleoptilar stage mature seed of Zea mays /aleuron /scutellum Triticum  Dicot embryogenesis ▪ Capsella bursa-pastoris serves as a good model for dicot embryogenesis. ▪ Embryogenesis stages : proembryo, globular, heart, torpedo, and cotyledon stages. Monocots: proembryo, globular, scutellar and coleoptilar stages Pro embryo stage Following fertilization of the egg and sperm nuclei, a pro embryo is formed Pro embryo stage by a transverse cell division to form an apical and basal cell. Globular stage ▪ Basal cell derivatives in globular embryo form hypophysis that develop into radicle. ▪ Tissue differentiation becomes evident in 16-celled globular embryo Globular stage Cotyledon stage ▪ Cotyledon primordium evident in heart-shaped stage of embryogenesis. ▪ These primordia elongate to give a typical torpedo stage embryo In heart and torpedo stages, embryo has organized to form apical meristem, radicle, cotyledons and hypocotyl Mature stage ▪ embryo is fully formed and separate cotyledons can easily seen as well as a distinct shoot and root meristem. ▪ suspensor and basal cell begin to disappears Perkembangan embrio pada Arabidopsis Scutellar stage globular Proembryo stage late globular stage Coleoptilar stage  Gymnosperm embryogenesis –Pine Micropil Tabung polen Seludang luar = integument luar Seludang dalam = integument dalam “free nuclear” Gametofit betina “seluler” Gametofit betina egg sperm Compared to angiosperms, embryo formation in gymnosperms differs in several important ways. 1. Seeds of gymnosperms are not contained within a carpel (fruit) → gymnosperm means "naked seeded". 2. No true triploid endosperm in gymnosperms. Developing embryo is nourished by haploid female gametophyte tissue  Pine Ovule The female cone consists of : ▪ stem (or axis) bearing scales, each of which is a modified branch, not leaf. ▪ These ovuliferous scales each have a pair of ovules on their upper surfaces. ▪ Each ovule contains a megasporangium (or nucellus) surrounded by an integument ▪ An opening in the integument, the micropyle, is where the pollen grain will enter for fertilization. Inside the megasporangium, 4 megaspores will be formed by meiosis. 3 megaspores will disintegrate but the fourth will develop into the haploid female gametophyte or megagametophyte. At maturity, the megagametophyte will consist of about 2000 cells plus a few archegonia each with an egg cell. Archegonium formed after pollination inside female conifer cones (megastrobili) Free nuclear stage After fertilization, several embryos begin to develop within a single gymnosperm seed but rarely does more than one of these embryos mature. The fertilized egg cell divides to form a free nuclear stage without cell walls between nuclei Suspensor tier stage Suspensor: primary suspensor cells (rosette Following cell wall formation,cells cells) and organize to form an embryo tier of cells and a suspensor tier. The suspensor differentiates into a set of embryonal suspensor primary suspensor cells (rosette cells) tubes and embryonal suspensor tubes suspensor Proembryostage The suspensor cells elongate and there are several cleavage events to give multiple embryos (polyembryos) inside a single seed. Usually, only one of these embryos continue to develop Cotyledon stage The pro embryo continues to differentiate an epidermal layer prior to multiple cotyledon primordia becoming evident in the cotyledon stage. Also, the shoot and root meristem has been developed  Although several eggs in an ovule may be fertilized, usually only one develops into an embryo. When more than one embryo forms (about 3-4% of the time), then one seed will be able to produce two or more seedlings upon germination. Female cones develop in the spring and are pollinated and then close when only 0.5 cm long. Fertilization takes place after the pollen matures, generally 12 to 14 months later. Pine cones then, are not mature until the fall of the second year following their formation. At maturity, they are large and woody and bear seeds on the upper surfaces of their scales. Pairs of seeds on the seed (ovuliferous) scales of Pinus sabiniana cone (tip of cone cut away) Pinus coulteri cone http://www.kbg.fpv.ukf.sk/studium_materialy/morfolo gia_rastlin/webchap10epi/10.2-4.htm Perkecambahan Biji Seed Germination (uni-hamburg.de) Ada pertanyaan? STRUKTUR BIJI Bagian-bagian biji Eksternal (luar) 1. Arilus, jaringan yang berkembang pada permukaan biji e.g. 1. Durio zibethinus, arilus tebal berdaging 2. Nephelium lappaceum, putih berdaging, enak dimakan 3. Myristica fragrans, arilus berdaging kering, berwarna merah 2. Elaeosoma, arilus yang mengandung minyak/lemak. Fungsi : penyebaran biji oleh semut  Carunculate seed of Euphorbia mafingensis Elaiosomes (elaios- oil, some- body): fleshy structures attached to seeds of many plant species. rich in lipids and proteins, may be variously shaped. attract ants, which take seed to their nest and feed the elaiosome to their larvae. *Elaioplasts is another name for fat-producing cells (plastids). in family Euphorbiaceae is called caruncle. Seeds that have a caruncle are carunculate, seed that do not have a caruncle are ecarunculate. 2. Testa Berkembang dari satu atau 2 integumen, dan (kadang) nuselus Struktur anatomi kulit biji/testa. A. Sinapis alba; Lapisan testa : B. Citrus aurantiaca 1. Sarkotesta – lapisan terluar 2. Sklerotesta – bagian tengah, tebal dan keras 3. Endotesta – lapisan terdalam, selaput tipis & berdaging Pada Gnetum gnemon, i. sarkotesta berwarna hijau/merah ii. sklerotesta keras berlignin iii. endotesta, berupa selaput tipis penutup endosperm Pada Punica granatum, sarkotesta berair 3. Rambut atau sayap Gossypium lapisan epidermis terluar dari testa membentuk rambut yang panjang Swietenia macrophylla – sayap 4. Mikropil, pori/lubang pada ovulum di tempat tabung polen mengantarkan sperma 5. Hilum: ‘scar‘ tempat/sisa pelekatan (titik temu) ovul ke ovarium 6. Raphe: bagian/tempat pelekatan funikulus dengan integumen pada biji dengan ovulum anatrop, kampilotrop 7. Karunkula: tonjolan lunak berwarna putih Hilum Radicle emergence Hilum mikropil  Eksternal (dalam) 1. Endosperm (poliploid) ❖ hasil pembuahan inti polar + inti sperma ❖ penyimpanan cadangan makanan & nutrisi untuk embrio Pada beberapa tumbuhan dikotil, i.e. Fabaceae, endosperm menghilang saat pendewasaan embrio Pada Nicotiana tabacum, Ricinus communis, endosperm persisten dan besar Pada tumbuhan monokotil, endosperm mengisi 70% biomassa biji 2. Embrio, bakal sporofit t.d. radikula dan plumula 3. Kotiledon ▪ Merupakan daun pertama ▪ Tempat penyimpanan cadangan makanan ▪ Organ fotosintesis pertama untuk tumbuhan  BUAH Struktur reproduksi tambahan pada tumbuhan Angiospermae Perkembangan dirangsang oleh adanya polinasi atau fertilisasi Di dalamnya mengandung biji (kecuali buah partenokarpi) Buah partenokarpi 1. Buah berkembang tanpa didahului oleh adanya polinasi, e.g. Musa sp., Ananas comosus, Citrus 2. Buah berkembang akibat adanya stimulasi polinasi tanpa dilanjutkan dengan fertilisasi, e.g. Poa sp. 3. Buah berkembang akibat adanya polinasi dan fertilisasi, akan tetapi terjadi aborsi embrio sebelum buah dewasa, e.g. Prunus, Vitis, Pyrus sp Fungsi Buah ▪ Organ tempat perkembangan biji ▪ Membantu proses penyebaran biji ▪ Air / angin ▪ Hewan ▪ Mekanik Asal Buah ▪ Ovarium/ bakal buah → buah sejati ▪ Ovarium dan/atau bagian bunga yang lain → buah semu Pada umumnya buah sejati memiliki dinding buah yang berdaging atau perikarp ▪ Eksokarp/epikarp – bagian terluar dari dinding buah umumnya tipis dan berkutikula ▪ Mesokarp – bagian tengah umumnya tersusun oleh jaringan parenkim ▪ Endokarp bagian terdalam, umumnya tipis MAJOR FRUIT TYPES Type Definition Examples SIMPLE From a single pistil DRY INDEHISCENT At maturity dry; does not split open Achene Close-fitting pericarp surrounding a single seed Sunflower Grain Close-fitting pericap fused to a single seed Corn, wheat Nut Thick, woody pericarp surrounding a single seed Walnut, hazelnut DRY DEHISCENT At maturity dry and splits open Legume Pod that splits along two opposite sides Beans, peas Capsule Fruit opening by several splits or pores Cotton, poppy Schizocarp Fruit splitting into 1-seeded segments Dill FLESHY Mostly fleshy at maturity; do not usually split open Drupe 1- to 2-seeded; innermost pericarp layer, stony Plum, peach and enclosing the seed(s) Berry 1- to many-seeded; no stony innermost layer of pericarp Tomato, grape, (all citrus fruit are berries of a special type termed a hesperidium) AGGREGATE Formed by fusion of several separate pistils of one flower Raspberry, cherimoya MULTIPLE Formed by fusion of several separate pistils of several Pineapple, fig grouped flowers Bean fruit x20. A "green bean" which is actually a fruit with seeds inside. The three layers of the ovary wall can be seen. The seed is obviously a dicot seed, with the two cotyledons filling most of the inside space of the seed. JENIS BUAH A. Buah berdaging 1. Beri, baka Buah yang memiliki daging buah lembut/lunak dan berdaging, kadang mengandung banyak biji e.g. tomat, pisang a. Hesperidium Buah baka yang terspesialisasi memiliki daging buah yang berminyak mengandung kelenjar skizolisigen. e.g. Citrus, grapefruit b. Pepo Buah baka dengan kulit/daging buah tebal bagian eksokarp memiliki tonjolan (accessory rind) e.g. Cucurbita moschata, Cucumis melo 2. Drupa Buah umumnya berbiji satu, dinding buah yang berdaging di bagian luarnya dan keras di bagian dalamnya (endokarp mengeras) Mangifera indica, aprikot, plum, olive, ra e.g. Apricot, Cocos nucifera ▪ Close-up view of 3 germination pores on the endocarp of a coconut. Only one pore is functional, each pore represents one of the three carpels of this monocotyledonous plant. ▪ An ordinary paper clip can easily penetrate the functional germination pore → allows the developing shoot to grow out of the hard, woody endocarp. The other two pores are impenetrable woody depressions. ▪ "Blind" coconuts apparently do not have germination pores. They are rarely produced and are the alleged source of coconut pearls. 3. Pome Pear flesh Buah semu berdaging dengan bagian tengah yang memiliki struktur menyerupai tulang rawan e.g. Pyrus malus B. Buah kering 1. Buah yang tidak pecah saat matang a. Buah Caryopsis (grain) buah berbiji satu, dinding buah bersatu dengan kulit biji e.g Zea mays, Oryza sativa b. Cypsela Buah semu berbiji satu, buah berasal dari ovarium inferior (bunga matahari) 2. Buah kering yang memecah saat matang alur perut Legume/polong Buah berasal dari satu karpel yang memecah sepanjang alur perut alur punggung  Fruit = a legume Gynoecium = 1 Carpel Bookmarks From fruit to flower ▪ Single Carpel http://www.google.com/imgres?imgurl=http://www.bot ▪ Dry any.hawaii.edu/faculty/webb/BOT201/Angiosperm/Legu meFruit ▪ Dehiscent on two sides Siliqua ▪ buah yang berkembang dari dua karpel ▪ memecah pada dua alur ▪ melepaskan kedua karpelnya dan menyisakan sekat ▪ Tipe buah ini merupakan salah satu ciri khas buah tumbuhan Brassicaceae A dehiscent elongated fruit, characteristic of the mustard family, having two fused carpels with the length being more than three times the width. as the fruit dries, two valves fall away leaving a central partition. Schizokarp (Splitting Fruits) ▪ Buah terdiri atas 1 - 2 merikarp ▪ Masing-masing merikarp tersusun atas satu karpel ▪ Pada saat buah matang, merikarp akan terpisah dan masing- masing terikat pada carpofor. ▪ e.g. buah Foeniculus vulgaris on ripening fruit divides into one-seeded segments or mericarp; but the mericarps remain un-ruptured. Pembagian Buah Berdasarkan Asalnya  Buah Tunggal, Majemuk, Agregat BUAH Buah Sejati, Semu Simple fruits : fruits that develop from a single ovary of one flower. This ovary may be either simple or compound.  BUAH MAJEMUK BUAH TUNGGAL  BUAH AGREGAT Fragaria/strawberry fruit x30. Strawberries are aggregate achenes. The fleshy part that you eat is swollen receptacle (flower stalk). You can see a dicot embryo in one of the tiny little achene fruits on the surface of the strawberry.  BUAH SEMU Buah tunggal semu Buah majemuk semu Ada pertanyaan?