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飘逸君子:ffice ffice\" /> FYI: Plant sexualityFrom Wikipedia, the free encyclopediaJump to: navigation, search <!-- start content -->
Close-up of an Echinopsis spachiana flower, showing both carpels (only the styles and stigmas are visible) and stamens, making it a complete flower. Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants. Among all living organisms, flowers, which are the reproductive structures of angiosperms, are the most varied physically and show the greatest diversity in methods of reproduction of all biological systems.[1] Carolus Linnaeus (1735 and 1753) proposed a system of classification of flowering plants based on plant structures, since plants employ many different morphological adaptations involving sexual reproduction, flowers played an important role in that classification system. Later on Christian Konrad Sprengel (1793) studied plant sexuality and called it the \"revealed secret of nature\" and for the first time it was understood that the pollination process involved both biotic and abiotic interactions (Charles Darwin's theories of natural selection utilized this work to promote his idea of evolution). Plants that are not flowering plants (green alga, mosses, liverworts, hornworts, ferns and gymnosperms) also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction. The breeding system, or how the sperm from one plant fertilizes the ovals of another, is the single most important determinant of the mating structure of nonclonal plant populations. The mating structure or morphology of the flower parts and their arrangement on the plant in turn controls the amount and distribution of genetic variation, a central element in the evolutionary process.[2]
Flower, showing both carpels (only the styles and stigmas are visible) and stamens, making it a complete flower. PEONY CULTURAL INSTRUCTIONS Peonies are easily grown and have minimal requirements, but respond beautifully to a little extra care and attention by producing their best quality flowers. We offer the following suggestions so your peonies will provide years of enjoyment. When To Plant Peonies may be planted in September through November before the ground freezes. Spring planting is not as desirable because the plants begin their top growth before the roots have become well established. Fern leaf peonies are usually planted in August and September. Where To Plant Select a sunny, well-drained location for peonies. They will tolerate some shade, but should have at least a half-day of sunshine. Do not plant near large trees or shrubs where they would be robbed of light, moisture, and plant food. If you want large specimen plants, space them three to four feet apart. Peonies prefer a soil with a 6.5 to 7.0 ph. Peonies will grow in one location for many years and do well. Once a plant has been dug, do not reset another in the same spot unless you have removed/replaced the soil. Peonies use rare elements from the ground when they fed, and these elements are difficult to replace. In addition, planting in a new location will eliminate the possibility of peony diseases that could occur where peonies grew before. How To Plant If you can’t plant immediately, keep the packing material moist and the plant cool. Before planting, remove the moss or other packing material from the roots. Prepare the soil before planting. For each plant dig a hole a minimum 18 inches deep and at least the same diameter. Heavy clay or very sandy soils should be amended with compost or replaced with good garden soil. If well rotted manure is available, use about three inches in the bottom of the hole, pack well, then cover with soil so the manure does not come in contact with the roots. Depth of planting is very important. The soil below the plant should be packed well so that it will not settle. When planting is completed the eyes of the plant should be 2” below the surface. From mid-Missouri mouth, the eyes can be planted one inch below the ground surface. Planting may appear to be difficult, but it’s a small task when you realize a properly planted peony will grow and bloom a lifetime. Fertilizing Fertile or properly prepared soil will require little fertilization for years. ffice:smarttags\" />Sandy soils lose fertility faster since it is washed out by rain. Keep fertilizer away from the crowns of plants as it will damage eye development. Spread fertilizer 6” - 18” from the crown and incorporate it into the soil. Use fertilizer sparingly as over-fertilized plants will not bloom well. About a half handful of low nitrogen commercial fertilizer per plant is sufficient. Use a fertilizer mix with a NPK ratio of approximately 5-20-30 or 6-24-24. Watering Water peonies thoroughly after planting so the soil settles well around the roots. During spring months there is usually enough moisture. However, if several weeks pass without rain, water every two weeks. Water peonies during dry summer months after the peonies have bloomed to help ensure a good crop of flowers the following year. Winter Protection Newly planted peonies should be protected the first winter after planting. After the ground has frozen, cover the peonies with straw or marsh hay about 3” deep. This covering will protect the plants against heaving due to alternate freezing and thawing. Remove the covering in early spring. Established plants need no winter protection, with the exception of fern leaf. Flowering The first spring after planting, your plant will make one or more stems. Do not be discouraged by lack of flowers. This is normal. First year flowers may be true to color but not to size or form. Growth/flowering increases each year. Plants produce normal blooms by the third year. Most varieties develop small lateral or side-buds near the base of the terminal bud. If larger flowers are wanted, remove the side buds so the strength will go into the terminal bud. Remove side-buds as soon as they are pea-sized by pulling downward and side ways. If you want, leave side-buds to prolong the bloom since they bloom later than the terminal bud. Disease Botrytis and other blights may attack peonies. In the spring, new shoots may suddenly turn black and die. Buds may turn brown and atrophy. The infection may spread downward on the stem and cause it to die and may even extend down to the roots. Leaves may develop brown spots, which spread and may kill the leaf. Spores from infected parts are carried by water and wind to other plants and are carried over winter in plant debris. Damp spring weather and poor air circulation tend to increase infections. Using fungicide sprays such as Bordeaux when peonies are emerging in the spring will help. In the fall, cut foliage at ground level, remove and burn | 
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发表于 2009-4-27 06:50:18
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