Reproductive Biology of Angiosperm

GORE-11 Reproductive Biology of Angiosperm (EMBRYOLOGY) Unit-1 Introduction: Sexual reproduction in Angiosperms is a basic and most important feature by which the plant produces seeds to propagate and produce offspring. →Reprodesction biology is a recent term in place of Embryology which deals with total reproduction process starting from forem off gametes till the form of plantlet inside the seed & it's development. Scopes of Embryology: Embryology, which originated as a simple study of the origin and development of gametes, has now expanded its scope to various fields. ⅰ) Embryology, besides a comparative & developmental study of embryo, has been integrated to form molecular embryology, applied embryology, ecological embryology, genetics of embryological features, embryology in plant breeding, crop improvement site. ⅱ) Various new aspects of embryology like the polarity of the embryo, the molecular basis of the embryo, genetics of selt incompatibility, environmental conditions of ditt. parts of eanbryosac, ovule, and ete have been worked out, and new information is being gathered. is Morden embryology now offers a vast scope of study to understand the origin, evolution, phylogeny, and also development talent, species? History :- • The sexual cells of flowers were firstly observed by Leeuwenhoek (1677). → Fore the finest time Grew (1682), stated that Stormens are the male ongan of a flowere. → Another scientist Commercarius (1601694) observed Ricinus & Zea mays & concluded that Anthers ane the male sex organ of the plant & ovary with style&stigona are the bemale sex organs. + J. Kondruenter (1761) studied about signéticance of pollination. He was able to identify the two distinct layers ots pollen grains. G.B. Amici (Giovanni Battista) finally revealed the actual role of pollen in gentilization. He stated that pollentube, after emerging brom pollen greain griew bit by bit and finally come in contact with the ovule. → In 1884, Edward Schottburger observed the fusion of mall gromete with female gamets (eggs), which is called Syngamy. Contribution of Famous Embryologists (Foreign) G. B. Amici Giovanni Battista Amici was an Italian astronomer & a mathematice on. → Armice was well known in the field off optical. instruments. He built d type of catadioptric microscope which wal free froon chromatic abberation. → while examining the stigma of Portulaca oleracea he saw a pollen grain adhering to a stigmatic hair. → Femnally Amici confirmed that the pollen tube emerging from pollen greaën and grew bit by bit & finally come in contact with ovule. He's contribution on the field of biology: i) 6. B. Apmnice observed that the streaming movement of protoplasm in Charra. i) He made remarkable observation in Plant anatomy, physiology, histology & plant pathology. • his discovery fore palisade ii) He is known bore his discove parenchyma in leaves. in) The discovery form which he become very famous was that of the Gentlization in phonerograms, particulady the travel of pollen tube through the pestel of flower. v) He was berest to observe the pollentabe. 2) W. Hotoneiston (1824-1877) Wilhelm Hofmeister was & Germon biologist whose work & contribution in the field of botany remain a landmark. F Hot mister's first botonical paper was published in 1847. → 'Die Entstehung des Embryoder Phenerogram' (The gensy of Embreys in Phenerogram) was written by him which was gave him an honorcany degree from university of Rostock. * His major contributions are - ⅰ) Through conetul dissection involving many species Hotomeiction showed the pollen tube & the egg both made contre bution tori development of embryo. a) Reabayo Mottermeister's second important contribution was the discovery of alternations of generations as a general feature in Plant libe. Li) He demonstrated that plants exist on two indeponderant form dening life cycle- gametophyte & sporcophyte. i) Hotmeister also contributed to many things in cellular studies and plant movements. I contributed phototropem and green troones of plants. 3) E. Strasborgen (1844-1912) → Eduard Starsburger was one of the most admirable scientist in plant biology bong in Warsaw, Poland. →His text books ane Das botomische Practicum, pauteshed Lehrbuch der Betonik bur Hochusen →The govt honoured stors borgen with the title of a Geheimer Regierungrasten 1887 Contribution is the wat the first to provide ein arccurate description of cambryosae in gymnaspenn ongiosperm and also double pentelization. i) He observed discovered tove fertilizatio ond syngamy. iy Me originated some leums like, photodoxis, chlorpart, cytoplasm, nucleuplarn, haplaid ok. ev) He concluded mom his observation that nucleus wat responsible for heredity of that it contained within the filaments the divided in substance which the halver beth the daughter. v) Strasbingen considered the male & female gov cells to be equivalent & beanere of heredity. He also concluded that bertilization depends on only he cell nu cei. vi) From his studies he viewed that asexually reproducing organisms were the cardien bonoms from sexually reproducing regimin. He presented thit in his article in Biologische Centralbclat M. Su Nawaschin (1857-1930) Sergey Coavrilovech Nawaschin way an Russion scientist mone knoom in embryology beled though he started hit ne seach in Mycology. In 1904 Russion Academy of Science neunded in the first Bon Promum. the firetame Contre bution is Hit hasic reasearch was. developed to the morphology and tournomy of Moctes and pororistic lengi." He dis commed Hen on the Chalazogamy in binches in 1985 and ing Discovery of double fertilization in 1898, by Nawraschin was the most significant contributin evs The last phase of his work on karyology. He contreituted Ito the comporateve Karyological trond in Cytology 5) WA-Jenson (1927-2014) → Dn. Willion August Jencen has a great American embryologist has a great contributin in bield of entryology. → I'm the field of embryology Pros. Jenson hai done a number oft works in cotton embryogenesis. Capsella, onchid embrysbry. Contribution i) Jensen had analysed the entrance & discharge of the polles tabe into the embryo sac • with the light of electron-mucrcoscopes. (4) the studied the zygote of cotton before it developed to embryo & described details the structinal & orgonellar chonger inside the zygote ) He had also made ultrastructural studies of early endosperm development & synerged changes in umbentilized cotton ovales. in vitme in He had also studied embryogenesis in Capselle by using dectron microscope. vs the had studiod cell development docing plant embryogenesis and the ultra structive & histochemistry of syneg synengids of coton J. Heslop & Harrison John Heslop-Horrison was a British Bauct "Known to the world bom hit countes on pollens and pollen pistel interaction. He was popularly known as Jack. He neciered on distinctione & awarde such as Disc brom Queen't eimeverity, The Gumar Endtmann Internatend Medal boc plan palynology, etc. Contribution i) me studied the pollengrain developrunt, also the appemance & home of cytoplasmic connections bom meiocyfer in onthers. is the major contributions of Jack wave in the triald of pollen, pollen wall & pollen-pisti'l interaction. se His coonk stated that outer pollon was a певно repository ture mobêle protein traction which ane neteared shantly aftere pollens alight on the neceptive stigma surface. in the chowed that stigma confolchas an extra- cuticulan glycoprotein layer (pellicle) which contain lecken-bonding race ptonsile. vy we had alto dove works in the belld of torxonomy and proved geography. Contribution of Famous Indian Embryologut 1. P. Mahesware (1904-1966) I'm the early 30-40's of 20th century India started taking lead in the field of embryology and the name Panchanan Maheswari stands foremost. → His book "An introduction to the Embryology of Angiosperms." (1950) is a masterly exposition of the subject & is still consup unsurpassable. This book was published by McGraw Hill book compang in 1950 ia milestone in En Embryology. → He debined experemental embryology the initiation & with a Iar that branch" not embryo embryological modification of view to under chemistry of various events. the physics and Contribution: ⅰ) Maheswari classitied embryology into - descriptive, phylogenetic and experimental aspects. > He used embryological features for taxonomic purpose. He investigated the embryological features of toxa & showed that in conjuction with morphology & anatomy embryology could be useful in identification of tara. iin ne recognised that embryology & morphogenesitare linked & should be studied together.. iny Mahesware joined in the University and bounded the dept. of of Dacca (Dhaka) botany in 1949. He & his group in Dept. of Botory of Delhi Univ. studied many aspects of embryology such as - -control of fertilization → invitro cultime of ovary & ovale isolated nucellus tissue, embryo, ceed & →Anthere culture vi) Mahesware & his group of students studied on the cause of seltsincompatibility and the methods to how to overcome it on various plant.. viy His keen interest in this subject & his obrenvationt and descriptions of the various aspects of his tudies have been described in his famous book "The embryology of angiosperm." vice) He laid boundation stone fore nucellare culture to obtain true clones of citrus & the endosperm cultiore bore the production of triploid plant in case of litrus, Oryza & Putranjiva Roxburghi ix) He is the foundere to editore of a journal normed Phytomorphology." & He also discovered the pseudo embayprac in podostemaceae... P. Mahesware was a popular speaker and cunitex alto on science subjects. The popular topics cini'ten by him" The planks that India gave to the world", "what coads "Botany in ancient India", "Plants history and politics ete. → He was corbenced the honorary degnse of doctim of science deneng the international Botanical. Congress held at Paris in 1954. He died dearth hu on 18th May 1966 in Dithi After his studies and school of embryd Dahi fat have been carried out by out by embrydogy.in his studente and colleguer like 8.M. Johuri, H.Y. Mohantom et a) B.M. Johni (1909-2003) Brij Mohan Johai was an embryologists next to P. Make swari. Johri coas the student of P. Make swani → Ar a Ideal student Johre take forward the studies of his teacher and became tomonl embryology in all over the could in the field of emb → Affere the death of Mahesware he headed. the Dept of Botory, Univ of Odli fream 1964 th → He was also eliced as a bellow of Indian national science academy & of Indian Botonical society. He got Sunderlal Hora Medal (1996) son his leve time achievement in Botany. The way also awarded the mone prestegeous Berbal Sahni gold medal of IBS in 1970. contribution: Johrik her neacconthou made a detailed soonk ots the morphology & embryology of taxa belonging to wide variety of angeosperm families. is Johne mainly wonhed on snluing taxonomical anomalies by the embryological beate features. ing on this bars Cuccutor wat removed from Convolvulaceae & raised to a new tomily for wecutaceae, come larly Trapa was included in ene new fommely Trapaceae. a in He worked on Sanatanalys especially and demonstrated that seeds of parasitic Contonales com be genominated in culture in the absence of natureal host on its stiroulue ) He also observed that Rousforaia have been deffecentiated from callul masses deweloping from the cultured embryo & endosperm. This i can unprecedented featine in angeosperme 1974. ve Another imp contribution was the development of a triploid shoot (briam cultimed endospor ton the Ist terme. vi) I'm 1964 Johri became succentull in onducing oxagonagensie short generation in endospeon cultiune. This expt was done in Expercapry coperessiformis plant. vui) He edited on contributed on worked on various international formour books such as ⅰ) Experimental Embryology of Vasaulen plant (1982) Embryology of Angiosperm (1984) ily Batory in India History & Progress (1994-15) ex) The symnosperms (1997) v) Dictionary of Economic Plants in India (6) ete Anthen & Pollen Biology Androecium whorl is the male neprostutive whored in a flower and the storment are the male Reproductive organs of a Howeve →Atypical starven has a belament, om onther & coronective. → Anthen is present at the terminal and of stamen the tilement of starven. Anthon Coremeztéve Fellarment Starmen Anthen: Structure & bunction A typical onther is tetras pocorngiate & bileted. → It has a column of sterile tissue, called commethin The lobes of anther is attached to the top of filament of stormen and bened by a midrib called connective - Each onthen lobes contren & longitudinal chamber called microsperangea me pollenicar. Anthere has produced which pallen grains ( Labere the two microspirangia of each lobe bure to forma single polentac. Anthare wall The cross section of a anthen reveals a wall di Henntiaed in to 4 layere: 1. Epidaurois 2. E victo the ceum 3. Middle layers 4. Tapetem. It is the outer most layer of onthere wall which consiste of blattened & streteched colle i At the maturity of onthen some epidermal cette at specific site got differentiated into small, speccattered cells that split at anker matinity. This site is stormim cies The cells of epidermis divide by onbeclinal division only. A matune onthen usually pentanm protective forme to the inner ticeved by preventing unterclose. Endothecium:- 1) Endothecium is the hypabermal layer of the ontherwall presunt fust below the epidermis. ⅱ) Normally endothecirm is sinale layered, but in some plants it may become multilayered. ily It is originates trom parieted layer & presunt in the protichescant part of onther. The radially clongated, highly cell of endothecium και vacuolated, uninucleated and often spend on noticulate thickenings. ) Mox. development of this layan attains when anthen is ready to dehisce tore the discharge of paten. viy calls of this byen develop tibnove bande which arice (mom the contre tongenteal walld & nun outwond and upward, candong rieradle cadradle vu) The watere ngential wall nemains thin and the watere tongential endo thesial layons around the junction of two sporangia dalt exihibit secondary thickening. vil) Endothecium librous bond provides mechanical fonce ton anthen dehiscence. 3) Middle layen- 1) Ove to these layere of celle below the endotheceum constetute is middle bayor. ux Middle byens may contain more than 3 tayar (Lilium) on. have be no midte layens (Wolbia, Vallisneria) in the callt of middle Cause one blattened, thinsellad, tiriinucleate & vacunlated. in Middle layana generally ephimenal ie they become crushed dereng bone of misraspore by meiosis The cellt of Manch raiddle bayon in many species contain which An development. mobilized during pollen Tapetun: is Tapeturn is the innermost layer of anther wall of attaint its marcemum development at the tatrad stage oft microsponagenesis. as st completely sorrounds with the sporogenow tissue in all four micro sparargea ⅲ) Typically tapatum is sing single layer of cells worth sad har dence cytoplasm & a prominent ruckus. iv) Tapetum is of great physiological signéticoncs or its bumeteand ane related to pollen developnient, and passing of all bond materiale through the layar to sponogenous teszw wy Taquatorian gote degenercated by berg kreging begining off anthere dehiscence. vi) According to Maheswane tagation is always parietal meand formed from the priman parietel layan during anther deudopront. Types of Tapetam Bating on the behaviour ott tapetal cells, tapetum. as Anveksid Tapetum (invasive / Paréplar media/syneigh b) Seinstong Tapetion (altoknown as Parietal/andalen A. Amoeboid Tapetum: The type of tapetin which shows candy breakdown of their innen & radial walls of cells old shows movement of the protoplast mare in is called amoeboid tapetum. to antharecovery 2) In this type, brusion of tapetal protoplast exccarey to multe nuclei tapetal periplasmodium on gates the beveloping microsomes. syncytium which engules Lii) These cells have high metabolic activity. is form of orbicules do not occur in such of tapetion. 1) Arnoebeod tapetion is except Hapetum. ction commonly zeen in monocots members of Paraces which have ser secnetory 8. Serestony tapeten ⅰ) This tapetiro is characterized by no change in the position of the constituent cely throughout the microscope development. iny There cells only degenerate at the time off pollen matinity wy Such type of tapetam a common in decale & in some monocota like members of peaceee-fleliacon in Presence of sporenpalenin geangels called orbicules & the characterstic features of suchtype of tapetam. Orebicules, are too bon med from pres-ocbicules se pro-ubinh bodlee. Ther pro-uhish bodies are continously bormed in the topetal eytoplarm. unis A tapetal mombrane is formed in the ceactor tapetum at the tetread stage. seanctory is It' originates trom the secretion of itapetel relly. wi) It is composed ofs sponapallonin, polysacharides like cellulose, small amount of pectin & Callose. Fane" of Tapedum: It helps in the ot pallems. supply of nutriente bon the developount It helps in break down st callore by seeneting an enzyme called callare. Ereakage off calloco is very imp for pollen development supplies the precursors bore horen oft sporeling span sparealexin which requires bon bormation of exine of pollens. ins Tapetum also provides the pollon wall proteins, there proteins play a nake compatibility en determining porophytic sellt They also supplice pollon couts substances called ar pollon hit & tryphine. HCONNECTIVE MICROSPOR Fig Ts of anthor MICROSPOROCYTES