Page 2 - Morphoanatomical investigations of cones and pollen in Cathaya argyrophylla Chung & Kuang (Pinaceae, Coniferales) under systematical and evolutional aspects
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V. M. Dörken and H. Nimsch                                        Feddes Repertorium 2014, 125, 25–38

            1990; Sporne 1965). Currently limited data are available   “sporophyll” or “microsporophyll” for the sporangia bear-
            on the morphology and anatomy of Cathaya and espe-  ing structure. Otherwise we would introduce  a priory a
            cially on its cones. Furthermore, the few available mor-  homology with leaves.
            phological data on the structure of pollen- and seed-
            cones are often conflicting (see Callaghan 2011). A very
            detailed study on morphology and anatomy of the vege-  3 Results
            tative organs was published by Hu & Wang (1984).
            Since 2012 an individual cultivated in the living collection   3.1  Morphology and anatomy of seed-cones
            of Hubertus  Nimsch, Bollschweil, St. Ulrich (Germany)
            has developed several pollen- and seed-cones. This was   Seed-cones are developed in distal parts of the crown.
            taken as an opportunity to investigate the cone-   Here they are arranged in distal parts of ascending
            morphology and cone-anatomy in detail. Anatomical   shoots, where several cones (4–10) are formed close to
            data about the seed-scale can be taken from the very   each other (Fig. 1A). The shoot axis and the lateral
            detailed study published by Hu et al. (1989). Thus, in the   seed-cones are developed sylleptically from the same
            present study, only additional data to Hu et al. (1989) are   terminal hibernating bud. Each seed-cone is inserted in
            presented.                                         the axil of a typical needle-like trophophyll (Fig. 1B). Bud
                                                               scales surrounding the seed-cones are absent. At polli-
                                                               nation in May seed-cones are erect (Fig. 1B) and be-
            2 Material and methods                             tween 4.2–5.1 mm long and 3.8–4.7 mm wide. The stalk
                                                               of the cone is between 3.5–5.6 mm long and 2.5–
            2.1 Material                                       3.1 mm in diameter. Several small needle-leaves, sig-
                                                               nificantly smaller than typical trophophylls, are inserted
            Seed- and pollen-cones were collected in the living col-  on the stalk and overtop the distal receptive seed-cone
            lection of Hubertus Nimsch, Bollschweil, St. Ulrich (Ger-  at pollination (Fig. 1C). In ripe seed-cones these leaves
            many) from a 2.5 m high and 14-years-old individual.   can still be found at the  stalk below the cone-scales
            This individual was grown from seed. It is cultivated as a   (Fig. 1E). There are no intermediates between needle-
            potted plant and overwintered in a temperate house.   leaves and cone-scales. The seed-cone consists of
            Pollen- and seed-cones were collected on 05.05.2014.   12–16 cone-scale/seed-scale complexes (Fig. 1D). Only
            Seed-cones were continuously collected at two week   the cone-scales in the middle of the cone are fertile.
            intervals untill September.                        Ovules are absent on the most basal and most distal
                                                               ones. At pollination the cone-scales are 3–4 mm long
            2.2 Methods                                        (Figs. 1D, 2A, B) and significantly larger than the ovu-
                                                               liferous seed-scales (1–1.5 mm) (Fig. 3E). At pollination
            Freshly collected material was photographed and then   only the cone-scales, whose tips are strictly curved up-
            fixed in FAA (100 ml FAA = 90 ml 70% ethanol + 5 ml   wards, are visible externally (Figs. 1D, 3D). The seed-
            acetic acid 96% + 5 ml formaldehyde solution 37%)   scales are deeply hidden  within the cone. The cone-
            before being stored in 70% ethanol. The cone-anatomy   scales in receptive cones are  bright red with greenish
            was studied from serial sections using the classical   bases (Fig. 1D), while the seed-scales are pale green. At
            paraffin technique and subsequent astrablue/safranin   the margin of the basal half of the cone-scales several
            staining (Gerlach 1984). For SEM-analysis the FAA-  glandular hairs are developed (Fig. 2B, C). The base
            material was dehydrated in formaldehyde dimethyl   of the cone-/seed-scale complex is slightly narrowed,
            acetal (FDA) for at least 24 hours (Gerstberger & Leins   however, not pedicellate (Fig. 2A, B). Cone- and seed-
            1978) and critical point dried. Sputter coating was done   scales are congenitally fused in the basal part. Each
            with a sputter coater SCD 50 Bal-tec (Balzers). The   scale is supplied by its own bundle strand (Fig. 3E). The
            specimens were examined with an Auriga  Zeiss  TM.   vascular bundles enter the cone axis as separate
            Macrophotography was accomplished using a digital   strands.
            camera (Canon  PowerShot IS2) and microphotography     At pollination time the  cone is widely open and all
            with a digital microscope (Keyence VHX 500F) equipped   cone-scales are distant from each other (Fig. 1D). After
            with a high-precision VH mounting stand with X–Y stage   successful pollination the cones close first by an elonga-
            and bright field illumination (Keyence VH-S5).     tion of the cone-scales and later by the rapidly develop-
                                                               ing seed-scales. One week after pollination the cone-
            2.3 Special terms                                  scales are 5–7 mm long, the seed-scales 4–6 mm. The
                                                               maturing seed-scales are greyish-green. The ripe seed-
            Most authors regard the coniferous microsporangiopho-  scales are brownish, strongly lignified and woody, be-
            res as microsporophylls.  We avoid using the term   tween   1.4–2.3 cm  long,  and  overtop  the  cone-scales,


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