Flowers should be cross-pollinated for maximum seed production, as self-pollination usually results in limited seed set. (Fig. 3-4 A-C) Within a week after flowers open, pollen is shed from the anthers. At this time the pollen is transferred to the receptive pistils. The pistil is not receptive until the flower sheds its pollen. After pollination and fertilization the ovary swells and in 3-5 months the seed matures. At maturation the former ovary, now the seed pod, will dehisce (split). Seeds are plump and their color varies from tan to purplish.
Once mature, the seed is dried at room temperature for about one week and then sealed in bottles or vials and stored under refrigeration. Stored in this fashion, viability will remain high for 3—5 years. Seed from plants that grow in the southernmost states of the United States such as Florida and Georgia will germinate if planted immediately upon maturation, but the percentage of germination is much lower than if they are given a cold treatment, called stratification. For maximum percentage and uniformity of seed germination, stratify seed as per directions given in Chapter 9. Uniformity of germination refers to the number of seeds sown that will geminate within a few weeks of each other. Some unstratified seed will germinate over a period of several months but some won't germinate until the following year. Provide all species except Sarracenia purpurea ssp. purpurea with at least 2 months of stratification. S. purpurea ssp. purpurea germinates best with at least a 4 month period of stratification.
Sow the seed on the appropriate medium and dust lightly with fungicide, keeping the environment humid, and warm, 70-85°F (21-29°C). Seedlings can be transplanted when they have produced 2 or 3 leaves in addition to the cotyledons.
This genus is physically easier to hybridize than most because of its large floral parts. After the flower has opened, the progress of pollen development can be followed by lifting a petal and looking inside the flower. When mature and ready for pollination, the yellow pollen grains are shed and accumulate in the cup of the umbrella-shaped style. A small brush or flat toothpick can be used to transfer the pollen to a receptive stigma. The brush is dipped in the pollen and then rubbed gently on the stigma of a flower. The stigma is receptive after pollen release. When flowers of 2 plants are cross-pollinated, they must shed their pollen at about the same time. To ensure a successful cross, transfer of pollen should be repeated once a day for 3-5 days. The procedure for hybridizing early and late flowering Sarracenia is explained in Chapter 9.
Before the flower opens, it is important that the flowers be covered with a piece of muslin, cheesecloth, paper bag or gauze to keep out insects that may be carrying pollen from other Pitcher Plants. Also, vitally important is good record-keeping. The crossed plants should be identified with a label made of permanent material such as plastic markers which should be attached directly to the plant if possible. Asexual Reproduction
1. Leaf cuttings: Remove the leaf (pitcher) with a small piece of the rhizome attached, dip end in Rootone powder and place in damp sphagnum moss. Dust the cutting and medium with a fungicide. Keep humidity high and provide bright light. Keep the temperature in the 70-85°F (21-29.5°C) range. Transplant when leaves and roots have developed.
Success rate is fair for cuttings without roots. It is 100% for cuttings with roots. (Fig.
2. Rhizome cuttings: Cut a rhizome into 1 in. (2.5 cm) lengths, being careful not to sever any roots. Dust the cut surfaces with a fungicide. Repot the rhizome pieces in a horizontal position and cover with about Vz in. (1.25 cm) of sphagnum moss. Treat them in the same manner as leaf cuttings. A very successful technique.
3. Crown separation: Some rhizomes have multiple crowns or growing points. Carefully divide the rhizome into separate plants by cutting the rhizome apart between crown regions. Dust cut surfaces with a fungicide. Then repot each crown separately. Very successful technique. (Fig. 3-6)
4. Bud induction (removal of growing point): Carefully remove all the pitchers including their petioles from a rhizome. Next cut off about 1 in. (2.5 cm) from the terminal end of the leafless rhizome and dust the cut surfaces with a fungicide. Plant the rhizome horizontally in the soil so that the top of the rhizome is at or just above soil level. Small buds in the leaf axil that were inactive will now develop into plants.
Plant the terminal rhizome section that was initially cut off the rhizome with the cut surface which has been dusted with a fungicide in the soil deep enough so that about V2 of it is buried below soil level. The tip will develop into a plant. Treat the tip cutting the same as leaf cuttings. By this procedure you can obtain up to 15 buds (the maximum we have ever obtained) or more which will eventually develop into individual plants from the horizontal rhizome. When several leaves and roots develop, the individual plants can be cut from the rhizome. (Fig. 3-7 A-C)
This procedure can be carried out on a growing plant, without uprooting it. This is best done during spring or early summer. Cut off an inch (2.5 cm) from the growing end and carefully remove all the pitchers including the petiole and the soil from the upper surface of the rhizome. In situations where the rhizome is erect, the same procedure is followed except, in this case, the whole upper portion of the rhizome will be above soil level. In many cases the plants with erect rhizomes do not have enough length to the rhizome to cut off an inch (2.5 cm). In this situation remove the pitchers and scrape off the growing tip with a knife or your fingernail.
5. Bud induction (without removal of growing point): There is a variation of the above technique in which the tip is not cut off. Instead, after the leaves have been removed, with a sharp, clean knife or razor blade slits about 3A of an inch (2 cm) apart are cut into the upper surface of the rhizome if it is horizontal, or on one side if it is growing vertically. The cuts should penetrate to about V2 the thickness of the rhizome. (Fig. 3-8)
In the first procedure the source of auxin that inhibits the development of axillary buds is removed, whereas in the latter procedure the cuts prevent the auxin produced by the growing shoot tip from reaching all of the lateral buds and therefore, does not suppress their growth. The former method will yield more plants per rhizome. Both techniques are very successful.
for making leaf cuttings.
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