Báo cáo lâm nghiệp: "Studies on Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) needle cuticles"

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Nội dung Text: Báo cáo lâm nghiệp: "Studies on Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) needle cuticles"

Studies on Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) needle cuticles J. Reinikainen S. Huttunen M. Turunen Department of Botany, University of Oulu, SF-90570 Oulu, Finland dies, needles were covered with gold-palladium Introduction (45 nm) with sputter equipment (Polaron E 5100) and micrographed with a scanning elec- The structure of plant cuticular mem- tron microscope (Jeol JSM-35) at 15 kV and an exposure of 45 or 90 s. For TEM, the needles branes and their permeability have been prefixed in 2% glutaraldehyde in a 0.1 M were studied intensively (Holloway, 1982). Bec- phosphate buffer, then washed with the buffer ker et al. (1986) studied the water per- and posffixed in 1% O in the same buffer. 4 0 S meability of plant cuticles and suggested Samples were dehydrated in an alcohol series and then embedded in Ladd’s epon. The light that cuticles are primarily mobility barriers microscope was used to evaluate the cuticles as far as water transport is concerned. and to select areas suitable for electron micro- They also showed that thin cuticles tend to scopic evaluations with a Jeol JEM 100 CX II be better and more efficient water barriers scanning-transmission electron microscope. than thick cuticles. In dusted leaves, a The enzymatic (4% pectinase, 0.4% cellu- naturally occurring clay significantly in- lase) isolation of cuticles was made by a creased water loss when deposited onto method adapted from Orgell (1955) and Sch6n- cuticles of young leaves (Eveling and herr and Schmidt (1979). The method (20% Bataille, 1984). However, the direct water, pectinase, 2% cellulase) developed by Lend- zian et al. (1986) was also used. gas, ion and anion permeabilities of coni- fer needle cuticles are less known. of Kt was studied using The penetration Recently, Lendzian et ai. (1986) and Heis- isolated cuticles from young pine or freshly ka and Huttunen (1987) studied enzymati- spruce needles. The equipment used for pene- tration studies has been described by Heiska cally isolated conifer needle cuticles. and Huttunen (1987). The needle material studied so far comprised different populations of Finnish pines and Materials and Methods spruces, some pine tree clones and seedlings following acid precipitation treatment, as well as some individual trees from polluted and clean pine and Norway spruce needle cuticles Scots forest environments. studied with SEM and TEM. For SEM stu- were
June under northern Finnish conditions, Results the Scots pine (Pinus sylvestris L.) needles about 2 wk later. The develop- The young needles of Norway spruce ment of a waxy cuticle takes a few weeks (Picea abies L. Karst.) develop in early
Discussion and Conclusions fully developed cuticle should be and the July. During the cold at the end of seen and rainy summer of 1987, the epistoma- The foliar response of conifers to simu- tal waxes of P. sylvestris remained unde- lated acid rain has been ranked as less veloped. The young cuticles can be easily sensitive (Percy, 1987). However, the cuti- isolated from needles (e.g., 3 d old pine cular permeability and structural integrity needles, 8-15 d old spruce needles) with have revealed a wide range of responses. a short incubation period of 1-3 d. The The K penetration through isolated + young cuticles are very brittle and easily cuticles of Norway spruce was lower than damaged. In young needles, the cutiniza- that of pine cuticles. This could be caused tion and lignification of epidermal cell walls by needle age differences. The pine are still incomplete and unstrengthened. In needles were about 20 d old, whereas the July, the incubation period needed for iso- spruce needles were over 30 d old. An lation of cuticles is about 7 d (20% pec- age difference of 10 d can be of impor- tinase, 2% cellulase) and these were used tance in young needles. Percy (1987) for penetration studies (Fig. 1The KCI found increased foliar uptake of 86 at Rb leaching from pH 3-treated spruce and pH 2.6 in one clone of Sitka spruce. ton pine needles was many-fold that of un- mobility within leaves or needles was only treated dry spruce and pine needles when affected at pH 2.6. Our observations of in- tested in early July. The cuticles used for creased K penetration after acid rain + penetration studies were also micro- treatment at pH 3.0 are similar. Damage to graphed. forest trees in northern areas has been attributed to the acid deposition and cold The needles of pine or spruce seedlings climate. The young needle development have less cutinized cells and the isolation seems to be one of the phases most of cuticle is easier than from adult trees. sensitive to acid rain. The needles in adult test trees around an industrial area have ’abnormal’ cuticles, therefore causing many difficulties with respect to isolation studies. Structural References changes and changes in water economy of needles have been observed. Becker M., Kerstiens G. & Sch6nherr J. (1986) On Lappish and northern Finnish pine Water permeability of plant cuticles: perme- needles, the extensive cutinization of both ance, diffusion and partition coefficient. Trees 1, 54-60 the anticlinal and inner periclinal walls of the epiderm was evident, which might be Eveling D.W. & Bataille D.W. (1984) The effect of deposits of small particles on the resistance one reason for the poor isolation results. of leaves and petals to water loss. Environ. Over the central periclinal region, the Pollut. 36, 229-238 thickness is about 1.3 ,um and the cuticu- Heiska E. & Huttunen S. (1987) Havaintoja lar layer traversed by greater cellulose minnyn neulasesta eristettyjen kutikulien lApAi- microfibrils about 1.2 gm thick. The cor- sevyysominaisuuksista (Preliminary measure- responding values for spruce cuticles ment of penetration through isolated pine nee- varied from 0.5 to 1.5 gm and the layer dle cuticles. In Finnish with English abstract). Aquilo Ser. Bot. 25, 32-38 with cellulose microfibrils was about 1 gm thick. The cuticles show a high degree of Holloway P.J. (1982) Structure and histochem- istry of plant cuticular membranes. An overview. structural integrity.
OrgeJl WtH. (195!) The isolation of plant cuticle : n t The Plant Cuticle. (Cutler D.F,, AMn K.t.. & with pectic erizyrrte5. Plant Physiol. 30,78-80 Price C.E., ods.), Linnean Society Symposium Series no. 10, Academic Press, London, pp. 1- Percy K.E. (!i981) Effects of simutated acid rain 32 leaf cuticular characteristics and surface pro- on perties. Ph.t3. Thesis, University of Bristol, U.K. Lsrtdzian K.J.. Nakiiama A. & Ziegler H. (1986) Sehonherr J. & Schmidt H (1979) Water per- W. : Isolation of cuticular membranes from various nmeability of plant cuticles. Planta 144,391 -400 conifer needles. Trees 1,47-53