Báo cáo lâm nghiệp: "Seasonal development of female strobilus of stone pine (Pinus pinea L.)"

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Seasonal development of female strobilus of stone pine (Pinus pinea L.) B. Abellanas J.A. Pardos Laboratory of Plant Anatomy, Physiology and Genetics, E.T.S. Ingenieros de Montes, Ciudad Universitaria, 28040 Madrid, Spain clone bank located Introduction pinea L. grafts growing in a at Castell6n, Spain. were taken monthly from Buds and strobili The stone pine (Pinus pinea L.) prevails July 1988, fixed in FAA (for- 1987 to July malin-acetic acid-ethanol), and stored in 70% as a fruit tree rather than as a timber tree. ethanol until dissection. Then the samples were Therefore, maximizing cone crops must dehydrated and embedded in paraffin. Serial be a primary goal for breeding perfor- microtome sections were cut 7-9 pm thick, mance (Pardos and Abellanas, 1988). stained with safranin and fast-green, and Establishment, by grafting, of clone banks examined under a light microscope. from selected provenances is a valid way to progress (Magini, 1965). Precise know- ledge of the 4 yr reproductive cycle of this Results species is necessary for an accurate eval- uation of cone production and manipula- tion of the selected clones in the banks. In April, just after flowering occurred, the development of the new long-shoot bud The object of the research described begins. The apical meristem enlarges and herein was to examine the morphology of initiates primary cataphylls and the first the female strobilus and to describe the axillary primordia. phenology of the reproductive cycle from seed-cone bud initiation to appearance of In July, the axillary primordia begin to the embryo. form secondary cataphylls, but they do not reach the differentiation stage, into either vegetative or reproductive structures, until December and Janua- December. During Materials and Methods secondary long-shoot buds diffe- ry, the rentiate, i.e., seed-cone buds and lateral- branch buds appear on the upper region Female strobili and potentially reproductive of the primary long-shoot bud. buds were collected from randomly selected P.
the embryo begins its development, which In February, the different bud types are will be finished at the end of this summer. distinct. At this time, the female buds initiate the first ovuliferous scales. How- ever, the short-shoot buds are still undif- ferentiated, and appear as simple primor- Discussion and Conclusion dia covered with a number of secondary cataphylls. They continue forming new cataphylls until March, when almost all the pinea L.) has a peculiar The stone pine (P. ovuliferous scales have appeared and the reproductive cycle because it takes one ovules begin to form in their axils. more year to complete than most of other Around late March early April, the or Pinus species (Owens and Molder, 1984; mature seed-cone buds open and pol- Pattinson et al., 1989). lination takes place. Afterwards, the stro- The main conclusion of this study is that bilus scales enlarge and the cone closes. the phases of female strobilus develop- Near the end of April, a hyaline cell ment in this species are similar to those of appears in the center of each ovule. other pines but the timing of some of them Division of this cell initiates the spongy is delayed. The first steps are similar but tissue. During the whole next year of female gametophyte development and development, few changes in the ovule fertilization are delayed over one year. occur; the spongy tissue enlarges, the pollen tubes grow through the nucellus and the different layers of the integument, which will become the seed coat, begin to References differentiate. Not until February of the third year of Magini E. (1965) Esperienze sull’innesto development does the free-nuclear stage all’aperto del pino domestico (Pinus pinea L.). of the female gametophyte appear in the Firenze, pp. 20 center of the greatly enlarged spongy Owens J.N. & Molder M. (1984) The re- tissue. From now on, the development of productive cycle of Lodgepole pine. Information the female is very fast. gametophyte Service Branch, Ministry of Forestry, British Columbia. pp. 29 the next month, the cell wall forms During and separates the female gametophyte Pardos J.A. & Abellanas B. (1988) El pino pinonero: especie forestal de interds fruticola. into many small cells. In April, the Frut Rev. Fruticultura 3, 162-170 0 archegonia appear at the nucellar end of J. & Geary TF. (1969) Pattinson J.V., Burley the gametophyte, with the egg cell well Development of the ovulate strobilus in Pinus formed. In early June, the egg cell has kesiya Royle ex Gordon (syn Pinus khasya developed large vacuoles and soon Royle) in relation to controlled pollination in afterwards fertilization occurs. In mid-July, Zambia. Silv. Genet. 18, 108-111l