Unit 4: Reproductive Biology

Unit-4 Pollination: *It is the process of treansgere of poll- -engrains from anthere to the stigma is called pollination It is of two types: 2% self-pollination 79 cross-pollination" sell-pollination It is also called autogamy. *It is, the treanster of pollengreeins groom antherc to the stigma of scame anthiere flower / to a flowere on the same plant. *It takes place both unisexual and bisexual flowers of the same plant. → It is of two types. Autogamy by Gertonogamy Autogamy It is the pollination of flowers by it's own pollen. Transger of pollengrain takes place ficom the anther to the stigma of same Flowere. It takes place An bisexual plants like wheat, rice, tea..ete. Geitonogamy dit *It is the trecenster of pollen grains ben. two lowers boren by the same plant. CL gunctionally enase poniration but gonosi cusera-potination. *Adaptation/contrivances for e019- pollination Cax Homogamy → 99 the condition in which asthens + and stigma of a flowers mature simultaneously. >>It is found in mirabilis, wheat, nice..etc. by Cle istogamy + C These are the bisexual Flower which nev en upens called creistagarny/crosed Flowert. The self-pollination is carricied out within the closed buds. is found in the prants oxalis etc. /Flowers like commelina 2 * The Flowers which are uponed & exposed arre called chasmogamous. -It is also found in commelina specios Sigrificance of self-pollination *Fertilization & production of progeny are always certain. It mainterin purrity veriety of trace and superiority of the Their is less wasteesse of pollens Disadvantages itt lecoeds to the loss of vigour & viability in Long reun. It is an extrrecen from of inbreeding.. *cross pollination mmm It is called allogamy... It is the transfere of pollengrains grom the anther of the flower of one plant to the stigma of the grow- -ere on another plant. Cross pollination within a species is called xenogamy. Adaptation/contreivances of cross pollination "It is a condition wherce pollens of the Hower do not grow orci, grow very slowly, 9f they goll on the sigma of the same flower. *It is gound in solanum, nicotiana.... etc. by Dichogamy It is found în bisexual flower, where star -men & caurpel mature at difgn, types * when gynocium matures earlier than canthen it is caused protogany. It is found in magnolia, cose, ete + when anthere maturces earlier than stigma, it is caled protoandry. ex: salvia, china rose-sete * It is the condition wherce aut autogamy is mech -nically ammposible due to the dif97, streuctural patte -rons in anther & style. ex: cruciferi, carryophyllaceae, gloriosa dy Hetercostyle It is the condition from which styles of diggn Length are found in hetercomorephic flowers. Ex: Dimorphism is found in jasmin, and trimorphism is found in oxeris. significance of crass-pollination It always results in heathy our offsprings, which can adaptation digan, climatic con- ditions. Hybrids are produce...... →Morre abundant & viabilities with greater storcage capacity are produce. It helps in elimination of digfective character & produce new varieties... Disaddvantages *It is a wastefull process as leerige no.af pollengreains are damaged. The chance of fertilization is Umited. Agents of ercoss pollination →Agents can be biotic (living.component& abiotic component): Biotic agent Entomophily-insect by zoophily - Animal cornithophily-Birds cheircopterciphily-Bap ex Malacophily snae, Abiotic agent Anemophily-wind (Air) by Hydrophily-water Self-incompatibility *The inability of certain garnets even gram genetically similar plant species to fuse with each other which is called self-incompatibility. (53) →It may be due to - *prevention of pollen germination *Retardation of growth *Detercioration of pollen tube aryeven дашик од писiear qusion. The terem (SI) was first coined stout in 1917. However kpermeater reported si in verbascum → si is found in arreound 116 Jarmilies of Angiospare Angiosperm. → some example incrudes poaceae, Fabaceae, solana -ceae. →s species doesn't produce seed ensest pollination. on Lead to normal seed on cross pollination. * Hence si is a mechanism to promode cross pol -ination. * Types: It is 09 70110wing types 1) Interspecific incompatibility →It regers to the incompatibility beth, species that prevents fertilization ben, gamets of distantly related species. 20 Intrraspecific incompatibility a when viable pollens of same or other individuals of same species preventing Fertilization it is called interspecific. *Based on metre types morphological geaturce si is again swo as Heteromorphic in this, there is morphological dign in Flower morphology like length of style & stamen. Each making like produce only one types of flower. It is of tuso types- ix Distyly & regers to two types of styje (short & Long) & starmen (low & high). It is found in the family prrimulaceae. fix Tristyly I refers to three types of style means cantheres & style arre 3 diggn, position in the glower which include short, medium & Long. *It is found in the family lythreaceae, * Homomorphic It is characterized by occurence of only one types of flowers in all the individuals 0f a species. It is governed by multiple lleis coured s-curvers It is found in the family poaceae, Nicotiana, petunia & breasica. → It is of two types a sporophytic si (SSI) by Gametophytic SJ (GSI) ab sporophytic S7 (SSI) C *when it occurs due to genotypes of sporcophytic/stigmatic tissues of plants from which the pollen is derived. It is seen the members of Brassicaceae, Astraceae by Gametophytic s (GSI) →It is controlled by genotypes of male gamet on pollen grain. It is found in the family Lilyaceae, Poaceae → ot always sabours ereass pollination.. Diggerence between GSI and SSI SSI 1 The pollens aarce 3 cells ix The pollens arce a cells. fi) vai viability of pollen in its viability of pollens is cong short lived. Lived. iii) Invitico germination is fri Invitro germination is easy. difficult. ivy stigma oen pistil always ivy stigma or, pistil always is weight position. is dry position. vy The intraction occures on vy The interactions occurs on stigma. style we got *Methods to overcome self-incompatibility (xerox) Invitro fertilization. It is a technique which is developed to over- -come incompatibility and other beracions. in this process the male gamets (pollengrain) & the Female gamet (pistil) arce isolated & induced to fuse under controved conditions. *It is genereelly involves 3-basic technique- 96 Isolation and selection of mare & Female gamets fis Fusion of gamers in isolated condition. fith single rygore condition It is found in the plants like Nicotiana, Brassica Plumbago.etc. The fusion of gamets can be done by ay Electric Fusion by carcium induced fusion. CY PEG (Polly ethylene glycol) include fusion. Significance not overcome on incompatibility barricion, It is tool for gametosomatic cell hybreid gerumation. *It is useful for studing moleculare basis for embryo -genesis & endosporte, gormation. fore reaising hybrids of unrelated plants. It is useful for reaisir way in crop development programme. It is a easy way in Cybrid *It is also called cytoplasmic hybreid on, somatic hybrid. It is gormed by the fusion of protoplast. → prrotoplast is the part of the plant which are forme mechanically or enzymatically by removing the cell wall of the plant cellu The protoplast Fusion is induced by BEG * Cybreid are cells or plants containing nucleus of bond species but cytoplasm of the both parents, The process is called cybrridazation. *Advantages of Cybreid www ivo diggercent parcental genoms that can't reproduce sexually arre recombined. *t overccomes sexual incompability baruciores. It is used to study mitochondicial researcch, her- biside resistance plant. It is used to study cytoplasmic male sterility 70 tomato & tobaco 4