Texte-livre de botanique, morphologique et physiologique . stnown est les cellules de baste d'Apocynaceoe fourni avec le pouvoir de l'extension et de la contraction. (Mohl, Vegetabilische Zelle, Fig. 27.) * la théorie de la croissance de la paroi cellulaire (comme de toutes les structures organisées) par intussusceptitionétait d'abord née par Nigeli dans son grand travail sur Les granules D'Amidon (1858). Comparer aussi Sachs,Handbuch der Experimentalphysiologie der Pflanzen, §114. 32 MORPHOLOGIE DE LA CELLULE. Organisation dans le même sens que nous parlons de l'eau de cristallisation; et comme le Latteris est indispensable à la formation de nombreux cristaux, s

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Text-book of botany, morphological and physiological . stknown is the bast-cells of Apocynaceoe provided with power of extension and contraction. (Mohl, Vegetabilische Zelle, Fig. 27.) * The theory of the growth of the cell-wall (as of all organised structures) by intussusceptionwas first originated by Nigeli in his great work on Starch-granules (1858). Compare also Sachs, Handbuch der Experimentalphysiologie der Pflanzen, §114. 32 MORPHOLOGY OF THE CELL. organisation in the same sense we speak of as water of crystallisation; and as the latteris indispensable to the formation of many crystals, so is the former to the structure of the cell-wall. It ismoreover, as weshall see, a peculi-arity of all organ-ised structures, thatthey contain waterof organisation, atleast as long as theygrow, because theyall alike grow by-intussusception. From what hasbeen said, it caneasily be seen thatthe concentric for-mation of layers ofa cell-wall growingby intussusceptionessentially differsfrom the repeatedformation of cell-wall round one andthe same proto-. FlG. 35.—Macrospores oiPilnlaria ^lobidifei-a, in optical longitudinal section ; to the left a stillunripe spore, in which the outermost gelatinous layer of the cell-wall is still wanting, which ispresent in the ripe spore to the right; the two outermost layers of the cell-wall of the latter(c and d) have assumed a prismatic structure, which is especially clearly manifest at <r; at rfstratification is feebly indicated at the same time. Seen from the surface the prisms appear likeareolae; the boundary surfaces of the prisms are, in the corresponding cell-wall-layer of Marsileasahuitrix, more solid and cuticularised, by which the appearance of a honey-comb is obtained.(Cf. J. Hanstein, Berliner Monatsbericht; Feb. 6, 1862, Fig. 17, and Book II. Rhizocarpew.) plasmic body; cell-walls enclosed one within another may be produced in this manner; these, however, must not be considered as layers of one cell-wall. This process is very

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• bookcentury1800
• bookdecade1870
• booksubjectbotany
• bookyear1875