. Contributions from the Botanical Laboratory, vol. 8. Botany; Botany. Fi^r. I an elon^'ated soap bnbble passes thronjxh the same foi'ms when allowed to shorten as it did when eloiij2:ate(l. Hnt no si^'n of fusion of the droplets appears, until thox are actually in contact with on<' another. Similarly, a globule i'eapproachin<2: the protoplast itself must actually c(une intcv ccmtact with the mass from which it arose l)ef(U'e it loses its spherical shape and starts to flow back into the plasma mass, even though the two are ('(umected at all stages by a thread f plasmalemma. It has been k
. Contributions from the Botanical Laboratory, vol. 8. Botany; Botany. Fi^r. I an elon^'ated soap bnbble passes thronjxh the same foi'ms when allowed to shorten as it did when eloiij2:ate(l. Hnt no si^'n of fusion of the droplets appears, until thox are actually in contact with on<' another. Similarly, a globule i'eapproachin<2: the protoplast itself must actually c(une intcv ccmtact with the mass from which it arose l)ef(U'e it loses its spherical shape and starts to flow back into the plasma mass, even though the two are ('(umected at all stages by a thread f plasmalemma. It has been known for some time (Chodat 1911) that when meso- plasm is included in strands persisting between protoplast and wall on plasmolysis, the cytoplasm rounds into balls on a thin threa ^. FiL'. '2 ,nay be pulled out into a long, slench'r thread, but will nm be droplets on this thread. The layer forming the thn-ad and the layer i'ormnig the balls must l)e distinct. PLASMALEMMA IN TllK DKAD I'Ut HOPLAST The smooth surface of a dead, swollen i)rotoplast can actually be torn awav bv the microneedh- (Fig. 2) allowing the mesoplasm to fh^w out into the' surnmnding m.'dium as a shreddy, granular mass which does n(d mix with the water. | This brittle external layer is the —,...—«t- structure which Pfkffkh rup- tured in acid-killed cells by de])lasmolysis. allowing dyes to penetrate through the crack> so formed into the mesoplasm. It seems to I'etain some of the tlifferential ])ermeal)ility of its living condition, but otherwise is very different from the fluid, extensile living layer from which it arose. Swelling of the pr(d«>- plasm toHows the death (d' unplasmolyze(l as well as plas- Uiolyzed cells. Since the ])roto- plast of an iinplasm«»ly/e pushed throng hthe wall until it pierces the outer layer Imt not th. toim- plast the swollen protoplast willc(dlapse until the tonoplast lies almost flat ,,o,nnst the wall. Appaivntlv the dead plasmalemma held back the thnd whic
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbotany, bookyear1892
