Meetings of the Royal Botanical Society Of
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Acta Bot. Neerl. June 161-171 40(2), 1991, p. Meetings of the Royal Botanical Society of The Netherlands MEETING OF THE SECTION FOR PLANT MORPHOLOGY, ANATOMY AND CYTOLOGY ON 26 OCTOBER 1990 al. Anatomy and Pyrolysis Mass Spectrometry unknown) (van der Heijden et 1990, Proceedings Peat 90, (ed. Sopo, R.), 148-163). Anatomical ofPeatified PlantTissues pp. changes were observed, however: the pith, as well E. van der Heijden and J.J. Boon. Unit for Mass cortex as the are easily decomposed, although the Spectrometry ofMacromolecular Systems, FOM cell corners are often retained. In areas where Institute for Atomic and Molecular Physics, decomposition is severe, high fungal activity is also Kruislaan 407, 1098 SJ Amsterdam and Unit for observed. Molecular Paleobotany, Hugo de Vries-Laboratory, University ofAmsterdam,Kruislaan 318, 1098 SM Amsterdam,The Netherlands Effect ofGrowth Rate and Age on Wood Aselection ofpeatifiedplant tissues, handpickedfrom Structure of East-Liaoning Oak and a Dutch peat deposit, were anatomically mass S. Zhang and Y. Zhong. Rijksherbarium, P. O. Box spectrometrically characterized and compared with 9514,2300 RA Leiden, The Netherlands native tissues. In this way, insight is obtained in the chemical and anatomical selectivity of the The effect of growthrate on wood structure of East- in Oak decompositionprocess peat deposits. Liaoning (Quercus liaotungensis Koidz.) was A selective removal of polysaccharides and a studied, and compared with the effect of age (ring trees structural modification of the lignin macromolecule number from the pith). Five dominant were are observed in both peatified Calluna stemwood and collected from Mt. Zhongtiao, North China. The Ericaceous rootwood. These chemical changes coin- studies revealed that age is a decisive factor controll- cide with severe anatomical changes, although the ing wood structure, while the effect of growth rate is state of preservation between different wood forming less important. tissues is rather variable: in peatified Calluna fibres, The effect ofage on anatomical characters shows the combined layer is whereas the S optimum curves which differ from character to S,/S2 gone 3 layer and compound middle lamella are preserved. character. For fibre proportion, the effect shows a Sporadically, fibres with a higher or lower grade of parabolic curve, with an optimum age from 25 to 35 observed. The wood show- for maximum size. decompositionare vessels, years ing swollen and gelified cell walls, are better preserved The effect of growth rate varies not only with than the surrounding fibres. A uniform thinning of anatomical characters but with the position within a the cell wall is observed in the rootwood fibres, which growthring (earlywood, latewood or the whole ring), often better in the of the width and The effect of are preserved centre root. ring range age. growthrate on Decomposition resistent wood vessels, as found in sizes of wood elements (fibre length & diameter and Calluna stemwood, are not observed in the wood of vessel diameter) is not significant. However, growth the root. rate shows a greater effect on tissue proportions. The bark of the Calluna stem is highly resistent Growth rate does not influence characters of either to decomposition. The periderm, which is the most earlywood or latewood significantly, but it shows a resistent tissue, is not modified. Minor anatomical greater effect on characters ofthe whole growthring. modifications such cell wall and Within of width than as thickening gelifica- a narrower range ring (less tion, are observed in the phloem parenchyma and about 1 -5 mm), with increasing ring width (or growth cambium. Mass spectrometric analysis of peatified rate), fibre proportionincreases rapidly, while vessel not bark reveals that polysaccharides are decomposed and parenchyma proportion (including vasicentric during peatification. tracheids) decrease markedly, then more slowly, and The stems of Sphagnum are very resistent to finally they remain more or less constant when ring The of width is than decomposition. mass spectrum peatified beyond a specific range (wider c. Sphagnum is still characterized by intense mass 3 0 mm). Growth rate shows little effect on the struc- peaks of polysaccharides, which points to an excel- ture of juvenile wood, but a significant effect was lent preservation of these compounds (mechanism found in mature wood. 161 162 MEETINGS of cell differentiation cell Bi- and Unitegmy in Impatiens express some type or even degeneration. F.D. Boesewinkel. Hugo de Vries-laboratory, It be hypothesized that, perhaps as a result of University of Amsterdam,Kruislaan 318, 1098 SM may unfavourable small occur in a Amsterdam, The Netherlands conditions, rings tran- sition where function available stage, they as a readily Within the the transition of bi- to genus Impatiens F-actin pool. unitegmy occurs. Impatiens glanduliferais one of the bitegmic, I. noli-tangere one of the intermediate and Deposition and Reorientationof Cellulose I. congolensis one of the unitegmic species. The Microfibrils in Cells of unitegmic condition arises by the upward growth of Elongating Stylar Petunia subdermal cells under the dermal outer integument, hybrida togetherwith the arrested growth and shifting of this A.M.C. Wolters-Artsand M.M.A. Sassen. integument along the inner integument to a more Department ofExperimental Botany, University of apical position. In the unitegmic species the earlier Nijmegen, Toernooiveld,NL-6525 ED Nijmegen, does and the The Netherlands outer integument not develop anymore single integument consists mainly of the former inner According to the Multinet-Growth-Hypothesis integument and the subdermal cells which grow far (MGH) (Roelofsen & Houwink, Acla Bot. Neerl. upwards. The endothelium becomes the inner layer of 1953, 2: 218-225), originally transversely deposited the singleintegument. microfibrils become gradually re-oriented towards This isafourthwayfor ovules to become unitegmic. In more axial orientations during cell expansion. order Other in which ovules become ways may unitegmic to establish the extent ofmicrofibril reorientation, we are: quantitatively studied microfibril deposition and the (a) reduction ofthe outerintegument, texture during elongation in stylar parenchyma and (b) fusion oftwo dermal integuments,and transmitting tissue cells of Petunia hybrida. (c) integumentary shifting of the inner integu- of From the inner surfaces very young cells in styles ment by a subdermal outer integument. smaller than 0T cm, the following sequence in depo- The study ofovules in taxa in which the change over sition was inferred: microflbrils were deposited in of bi- to unitegmy takes place, gives information on alternating S- and Z-helical orientations. First nearly the evolution of the unitegmic ovule. axial orientations, followed by oblique and nearly transverse orientations. Together with the increasing Actin Rings are a Regular Constituentof pitch, the density increased. Only nearly-transverse PlantCells S- and Z-helical orientations were deposited during H.M.P. of Kengen. Department Experimental elongation. The wall maintained its thickness and Toernooiveld Botany, University of Nijmegen, 1, initial texture. 6525 ED The Netherlands Nijmegen, In cells the from axial young stylar sequence to transverse microfibril orientations reflects the way in Rhodamine-labelled phalloidin was used as a probe which microfibrils are deposited. Duringelongationa to study F-actin distribution in suspension cells of continuous deposition of nearly transversely oriented Nicotiana and Tagetes, and pollen tubes ofLilium. In microfibrils takes place. However, no perceptible addition, we also studied elongating suspension cells, changes are observed in the total texture during cell protoplasts from the suspension cells and subproto- expansion. The initial texture is maintained asa result plasts from pollen tubes in Nicotiana. Actin rings were ofpassive re-orientation, asdescribed by Roelofsen & present in all cells studied. In each preparationring- Houwink. The extent of passive re-orientation is in like structures were observed in about 5% of the cells with the theoretical calculations of Preston which occurred after fixation with paraformaldehyde agreement (Planla 1982, 155: 356-363) and shows that the total in PIPES-buffer (Traas, 1984, Protoplasma. 119, reorientation is limited to 40° in transmitting tissue buffer 212-218), as well as after extraction in PIPES cells and 59° in stylar parenchyma cells. with non-ionic detergents (Traas el al. 1987, J. Cell Biol.. 105: 387-395), Simultaneous visualization offluorescent and phase The Apertural System in Nephelieae Pollen contrast images revealed no perceptive association (Sapindaceae): Form, Function, and with organelles.The ofrings duringorganelle presence Evolution division (Hasezawa el al. 1988, Proloplasma, 146: R.W.J.M. Van der Ham. Rijksherbarium/Hortus 61-63) could not be confirmed. Botanicus, University of Leiden, P.O. Box 9514,2300 As the rings are present in a limited number ofcells RA Leiden, The Netherlands of the (about 5%), they may express a specific stage The cell cycle. At present, their occurrence in synchron- Nephelieae represent a rather eurypalynous tribe ized cell cultures is studied. Alternatively, they may ofthe family Sapindaceae, both with regard to exine MEETINGS 163 architecture and apertural system. The apertural 1989, New Phytol. Ill, 323-358). These distributions system is tri-aperturate. Three types occur in the 12 were observed in pollen