Kato, Kazuo

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RIGHT:URL:CITATION:AUTHOR(S):ISSUE DATE:TITLE:A Phenomenon in the Early Stageof Pollination in Secale cereale ; theStigma ReactionKato, KazuoKato, Kazuo. A Phenomenon in the Early Stage of Pollination in Secale cereale ; theStigma Reaction. Memoirs of the College of Science, University of Kyoto. Series B 1953,20(3): 203-2061953-08-05http://hdl.handle.net/2433/258395Memoirs of the College of Science, University of Kyoto, Series B,             Voj. XXI, No. 3, Artic]e 11, I953          A Phenomenon in the Early Stage of PollinatioR              in Secale cereale ; the Stigma Reaction                                 By                           Kazuo KATO                    Botanical Institute, Kyoto University                        (Reeeived Marclt 31, 1953)    Despite its importance, our knowledge of the ehanges and activities inboth of tl}e stigma ce]ls and ti]e pollen grains, especially at a very earlystage after pollination, is surprisingly meagre, exeept for the works ofSTRAsBuRGER Q886) and FITTiNG (1909, 1910), and a further investigationis needed. .    en the effect of pol]en grains on stigma cells, it was found by STRAs-BuRGER (1886) in crosses betwee]x species ef Orchis (O. masculataÅ~O. Morio>that the short pellen tube once emerged on the stigma is disorganized andt}ie papil]ae of tlie stigma are turned brown in colour at the coiitact pointwith tlie pol]en tube. According to him the colour change of the papillaernay also be eaused by ungerminated pollinia of Orchts pttsca on O. Morto.From these facts it is seen tlrat the pollinia give a certain change on thenature of the stigma ee]Is by tlieir contact at the pol]ination. Along asimilar line remarkab}e investigations, both in observational and experimental,were made by FiTTmG (1909, 1910) on Orclzis.    In Secale cereale, it has been found by the present author that the stigmacells differ in stainability ef their nucleus, according whether they are po]li-nated or not. This subiect has been taken up again and an investigationis in progress, a part• of which will be reported here under as preliminaries.    The style of SecaZe cereale is bi-forked into twe stigmas at its base, andnumerous stigma fxlamsnts are bem on these two stigmas for their entirelength. The stigma cells composing the filament are arranged in four rowsand their upper end is bent outwards, forming a shelf on which a po]len grainmay easily be placed <Figs. I and 2>. In the stigrna cells their nucleusoccupies the central position, and at both ends ef the cells a ]arge vacuo]eis sqeB. AloRg the cell wall and around the nucleus there is scanty cyto-p}asm in a thin layer, in whieh a few leucoplasts are contained.    When the pollinated style placed on a slide glass is stained with ordi-nary aeeto-carfnine, it is recoogniizab]e, in a s}iort while, that in the stigma fila-ment into whieh the pollen tube has been entered, the nulceus is stainea deeply,  204 Kazue itTo whereas other stigma filaments free from pollen grains, remain unstained (Fig. 1). As shown in Fig. 1, the difference in tlte stainabiiity of the nuclei is distip.ct at a eertain time after application of the aceto-earmine. This difference, however, is lost in about 20-30 minutes after the preparatien, the nuclei being stained equally in th.e twe kinds of fi]aments, pollinated aR(l non-pollinated (Fig. 3).     In order to determine the shortest time necessary for stigma cells staining by pol}ination, the action time of the pollen, narnely, the interval between the po}]ination and the application of aceto•carmine, was gradually shortened. By tlius shertening tke action time, one observes that in cases where the pol}en grain has net put out a polle)t tube, the stigma cell to which this ungerminated pol}en attaches is stained deeper in celour than otlter non- attaching cells.     In SecaZe cereale, the po]len tube, in favourable condition, emerges from the germ pore, in one minute or more but in less than two, after the fa}l of pollen grains on the stigma. So tlte action time of the pollen was shortened.from the grade of minu'tes to that of seconds, namely, from 50, 40, 30, 20 to 10 seconds;k. In all these cases an easy stainability of the pollinated cell is reeo.optizable. Accordip.gly, in order to manifest the easy stainability it is not necessary to etater the po!len tul}e into the stigmatic tissue but suracient only to contact the pellen grain on the surface of the stigma cell for a short while (Fig. 2). ffowever, as tlte action time of the pol]en is shortened, the time that reguires for being stained ef the nucleus is preioBged.     In consequence of the po}}ination., various c}ianges, other thalt the easy stainabiiity, take place in the stigma cells. Among the changes, those in permeability to various stains and other substances; in shape and structure of t.he nucleus; and withering of the stigma cell, may be enumerated. To all physico-chemical changes wliich oecur in the stigma ce}ls by pellination, the term `stigma reaction' is proposed, and for convenience ef description this term will be used in the fol}owing.     It is usual that the stained ce}ls are foulidi more numerous in nllmber in the aniiccal direction of the filament from the pollb:ated cell than in the basal direction. It seems that when a stigma reaction takes p]ace in a stigma ce}l this reaetion is not only restricted withiR this cel} but it may pass to neig}ibouring cel}s of the same filament, as seen below•     A case was observed where between two closely placed filaments one po}}ell grain was lodged, and its poi}en tube had penetrated into one of these filaments. In tliis ease the stigma reaction was reeo.ffnized in botli these filaments. In other words, in order to eause a stigma reaction it is not    ee ll\LtBiaSaht?gkEning of the action time diMculties are accompanied in n]aking the         A Phenomenon in the Early Stage of Po}lination in Secale cereale 205necessary to attaeh the pollen grain to a stigma cell at the germ pore butsufficient te attach it at any place of the pollen surface. This subcrgeststhat the pollen grain }ias a su})stance w}}ich acts on the stigma cells to changetheir nature, and that at the ineeptioii of germiRation this suppesed sulbstanceis activated a]l oveT the surface of thepoUen grain. The stigma cells be-tween which the po]]en tube has entere{i are more readilly stained with theaeeto-carmine as eempared with tlaose io which the ungerminated po]]en grainattaches. JJkis indicates that the pollen tabe also sets free a .similar sul]-stance which cau.ses the stigma reactio]i.    T.he stigrna reaction oceurs in immature as we]l as in mature stigmas.In their immature state the stigma filamaents are of a form of smooth celumnand not feathery (Fig. 4). 6n tl}e surface ef sueh stigma filame3its too,pollen grains may germinate and their po]]en tube presents a winding form,since between the cel]s no gap has not been formed iwato whieh the pol}entube to enter. In the young stigma filametats the aeeto-carmine penetratesso easily into the ce3]s that the stigma reaction is recognizable only in a shortduvation after an app]ieation of aceto-carmine.     S• cereale is knDwn to have a strong tendency to self sterility, }]ut thestigma reaction is seeR in both cases of neighbeur pollixxation and strietly efse}f pollinatien. .     In the stigma reaction, its first manifestation is the increase in permea-bility of the eell membrane in the pollinated stigma cel]s. To this changefollow changes of the nucleus in shape and strueture. In a n4tural andnon-pollinated state, the nuclei in the stigma cells are spherical in shape andtheir inner structure is apparently gTanular. Within a short minutes afterthe pellen attachment ne discernible change is seen in the nuclear structure,even where the pollen tube has enteretf eneugh in the stigmatic tissue.Twenty minutes or more after the pollination, withering of the stigma fila-ments is conspicuous. Due to the withering the stigma ce]]s become moreer less narrow in wi{ilth and in which the nuc}ei change their shape fremspherical into e}}ipsoidal. These nuclei are $till granular ane no discerniblecliatage is seeii in the stTuctuTe, but they take up readily the stain beingcoloured more deeply than the spherieal nuclei. The e}lipsoidal nucleus hasa tendency to move towards the ap!cal in tke cell.     In cases wlien the pel]en grain attaches anywhere midway of the stigmafilement and the action time of the pollen is long enough, the el]ipsoidalnuc]ei are fouud to be more numerous in number in the upper cells of tliefilament from the polnt of the pollen attachment than in the lower cel]s,This situation eorresponds with the above-mentioned fact that the easierstainabi]ity ef the stigma cells <nuc}ei) is presented in the apical part of thefilament from the peint of po]]en attachment than in the hasal.     When the action time of po]leB grans is long iA grade of 1iours, tlie 206 Kazao KAvenuclei take other shapes than spherial or ell!psoiGal, and t}]ere may be foandthose of fasiform and vermlferm. IR suck nuc]ei, the nuc]ear ti}reads coa}escein  pi lgez i fs.gh.'a5::,2aeg,nv,"iggem}igwa2,[Sli3 Z Y81I?.ig,,&O.'me8,\gh,the nucleu$ becomes obseure in conteur and is melted into cytoplasm(karyelysis). In very withered stigma ee]ls, pollixated naturally in the field,it is usual t}}at tlke nucleus is broken into pieces as giobules stained rea withtlie carmine. In these globules no structure can be seen.                             Literature CitedI"vrTiNG, H. (19C}9) Die Beeinfliissung der Orchideenbttiten dtirch clie Besttiubung und aiideye     Umsttinde. Zeit. Bot. Bd. I.- -t----------•m.-- (l910) Weitere EntwicklungsphysiologiscineUntersuchungen anOrchideenblitten.     Zeit. Bot., Bd. 2.SmAsBuRGER, E. (l886) Ueber fremdartige Bestgubung. .lahrb. f. wiss Bot., Bd. 17.                         Explaiiation oÅí PlateFigs. 1-4s, are photomicrographs oÅí' stigma fltaments in Seca•Le cerea•Le. 'Yhey are taken     from aeeto-earmine pTeparations. Magnlfication in a]i Åíigares is ca. 300x, except fQT     Fig. 4i, which is ca 600Å~.Fig. 1. While nuclei are stained in two stigma filaments, into each of which a pQilen tube     has entered, those in otheT filaments witli no polien grain, remain unstained.Fig. 2.. Nuelei are stainecl in only one filament, to whic} a pollen grain attaclaes.Fig. 3. 'Stigma fj]aments in prolon,cred staining. A'uciei are stainecl in al} filaments, whether     they are pollinated or net•Fig. 4,. Young stigma filaments shewing no projection oÅí their compo$in.cr cells.

A Phenomenon in the Early Stage of Pollination in Secale cereale ; the Stigma Reaction

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A Phenomenon in the Early Stage of Pollination in Secale cereale ; the Stigma Reaction

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