1. How to design plants according to their light demand in garden plant configuration? How to effectively improve the utilization rate of light energy?
Light is an indispensable energy source for photosynthesis of green plants. Only under light can plants grow, blossom and bear fruit normally. Light can also affect the morphological structure and anatomical characteristics of plants. The influence of light on garden plants is manifested in three aspects: light intensity, light time and light quality.
1. Influence of light intensity on garden plants
Light intensity mainly affects the growth and flowering of garden plants. The requirements of landscape plants for light intensity are usually expressed by compensation points and light saturation points. The light compensation point is the light intensity when the carbohydrate produced by photosynthesis and the carbohydrate consumed by respiration reach a dynamic balance. In this case, plants will not accumulate dry matter. When the light intensity exceeds the need of compensation point, the photosynthetic intensity will increase proportionally, but after the light intensity increases to a certain extent, the photosynthetic intensity will not increase again. This phenomenon is called light saturation, and the light intensity at this time is called light saturation point. According to the different requirements of light intensity, garden plants can be divided into positive plants, negative plants and neutral plants.
(1) Positive plants Positive plants like strong light, are not resistant to shading and have high light compensation points. Only under the condition of sufficient sunshine can they grow normally and exert their maximum ornamental value. If the light is insufficient, the branches are slender, the leaves are yellow and thin, the flowers are small but not bright, the fragrance is not strong, and the flowers are poor or cannot bloom.
Positive plants include most flowers and fruits and a few foliage plants, such as a bunch of safflower, jasmine, hibiscus, pomegranate, citrus, rose, palm, rubber tree, ginkgo and crape myrtle.
(2) Negative plants Negative plants are mostly native to the shady slopes of tropical rain forests or alpine forests, with strong shade tolerance and low light compensation point, and grow well under moderate shade conditions. If the strong light is direct, the leaves will turn yellow and wither, and after a long time, it will cause death.
The negative plants are mainly foliage plants and a few flowering plants, such as orchids, asparagus, Hosta, hydrangea, Eupatorium odoratum, ferns, Pearl Plum, mosquito mother trees, pittosporum, coral trees and so on.
(3) Neutral plants grow best under full light, but they also have different degrees of shade tolerance, and their growth is inhibited under high temperature, drought and full light. Among neutral plants, it includes both positive and negative species. For example, elm, Pu Shu, cherry blossom and Pterocarya stenoptera are neutral and sunny; Sophora japonica, Schima superba, Aesculus chinensis and Acer mono are neutral and slightly tolerant to shade; Abies, spruce, ivy, hydrangea, camellia, rhododendron, pittosporum, honeysuckle, Podocarpus, Phoebe bournei and Pteroceltis tatarinowii are neutral and have strong shade tolerance. The relationship between plants and light intensity is not fixed. With the change of age and environmental conditions, there will be corresponding changes, sometimes even great changes.
2. The influence of illumination time on garden plants
The length of light time has a significant effect on flower bud differentiation and flowering of garden plants. Some plants need to bloom in the season with short days and long nights, while others need to bloom in the season with long days and short nights. The periodic adaptation of plant flowering to different day and night exchanges is called photoperiod phenomenon. According to the different requirements of garden plants for light time, they can be divided into the following three categories:
(1) During the growth of plants with long sunshine, there is a period when they need longer sunshine hours every day, or the length of the night must be shorter than a certain number of hours, that is, the sunshine hours every day need to exceed 12 ~ 14 hours to form flower buds, and the longer the sunshine hours, the earlier the flowers bloom. Otherwise, it will maintain its nutritional state and will not blossom and bear fruit.
Gladiolus is a typical long-day plant. In order to supply cut gladiolus flowers all year round, in winter, in addition to high temperature, electric lights should be used to increase the illumination time. Ornamental plants that bloom naturally in late spring and summer are long-day plants. If measures are taken to extend the sunshine time, it can promote early flowering.
(2) The growth process of short-day plants needs a period of short days and long nights, and the daily light hours should be less than 12 hours, but more than 8 hours, which is beneficial to the formation and flowering of flower buds. Poinsettia and chrysanthemum are typical short-day plants, which only grow nutritionally in the environment of long sunshine in summer and do not bloom; After autumn, the sunshine time is reduced to 10 ~ 1 1 hour, and flower bud differentiation begins. Most plants that bloom in early spring or late autumn belong to short-day plants. If measures are taken to shorten the sunshine hours, it can promote early flowering.
(3) Among sunshine plants, sunshine plants are not sensitive to sunshine time. As long as it is mature and the temperature is suitable, it can bloom all year round, such as rose, hibiscus, geranium and canna.
The further study of photoperiod proves that in the photoperiod phenomenon of alternating day and night, the length of night plays a decisive role in plant flowering. That is, long-day plants must bloom at a critical night shorter than a certain length, while short-day plants must bloom at a critical night longer than a certain length. It is generally believed that the length of night affects the formation of flower primordium, and the length of sunshine affects the number of flower primordium. Therefore, whether it is a long-day plant or a short-day plant, sunlight is beneficial to a large number of plants after satisfying the cycle of alternating day and night.
The requirement of flowering time for plants is the result of their long-term adaptation to some photoperiod changes in the distribution area. Short-day plants all originated in the south of low latitude, while long-day plants originated in the north of high latitude. Generally, short-day plants are introduced from the south to the north. Because of the long sunshine time in the north, the vegetative growth period is often prolonged, which makes them vulnerable to freezing injury. When long-day plants are introduced from north to south, although they can grow normally, their development period is prolonged and they can't even blossom and bear fruit. Therefore, attention should be paid to the demand of plant growth and development for photoperiod in plant configuration.
3. The influence of light quality on garden plants
According to the different wavelengths of sunlight, it can be divided into short-wave light (wavelength 390 ~ 470 nm), extremely short-wave light (wavelength 300 ~ 390 nm) and long-wave light (wavelength 640 ~ 2600 nm). It is generally believed that short-wave light can promote plant tillering and inhibit plant elongation; Long wave light energy promotes seed germination and plant growth; Ultrashort wave promotes the formation of anthocyanins and pigments. This is why the extremely short waves near the mountains and equator are strong and brightly colored. In addition, the presence or absence of light and the intensity of light also affect the opening time of plant buds. For example, Scutellaria barbata can only be opened and closed after sunset under strong light; Epiphyllum blooms at night.
2. How to rationally allocate plants according to their adaptability to water?
According to the different requirements of garden plants for water, they are generally divided into four types:
(1) Drought-tolerant plants Drought-tolerant plants are mostly native to tropical drought or desert areas. These plants have developed roots, succulent plants can store a lot of water, have high cell osmotic pressure, and their leaves are hard, rough or completely degraded, such as cactus, Haloxylon ammodendron, black birch and Lespedeza.
(2) Mesophytes Most garden plants belong to this type, and they can't stand conditions that are too dry and too humid. Common varieties are Clivia, Rose, Fusang, Jasmine, Pomegranate, Lilac, Osmanthus fragrans, Liriodendron chinense, Platanus acerifolia, Loquat, Red-leaf Plum and Sophora japonica.
(3) Humidity-tolerant plants Humidity-tolerant plants are mostly native to tropical rainforests or mountains and streams, and like to live in an environment with high air humidity. In dry or moderate environment, they often die or grow poorly. Such as narcissus, bamboo, calla lily, taro, Metasequoia glyptostroboides, weeping willow, Fraxinus mandshurica, Guangdong Evergreen and so on.
(4) The roots or stems of aquatic plants generally have well-developed aeration tissues and are suitable for growing in water, such as lotus, water lily and Wang Lian.
1). Waterfront plants should pay attention to artistic composition. In China gardens, weeping willows have been planted at the water's edge since ancient times, so that soft strips can be brushed with water. At the same time, planting Pinus tabulaeformis, Pinus densiflora, Metasequoia glyptostroboides and Ficus microcarpa with drooping air roots near the water can play a role in composition. However, the arrangement of waterside plants should not be equidistantly planted, shaped or trimmed, so as not to lose the meaning of painting. In composition, pay attention to the use of branches and trunks that explore the water surface, especially those trees that seem to have fallen by the water, so as to increase the level of the water surface and be full of wild interest.
2) Plant arrangement of revetment Revetment is divided into earth embankment, stone embankment and concrete embankment, and its plant arrangement principle is that it can not only integrate mountains and water, but also play a leading role in water space landscape. The arrangement of plants on the embankment should be combined with the layout of topography, roads and coastline, which are near and far, sparse and dense, intermittent and continuous, tortuous and natural. Stone bank lines are blunt and boring, and the principle of plant configuration is Mei Lu, which covers up ugliness and makes it soft and changeable. Generally, willows and spring flowers are arranged on the embankment, so that the slender and soft branches are vertical to the water surface to cover the stone embankment, and at the same time, flowering shrubs and lianas such as Potentilla discolor, Acorus calamus, Swallow flower and Parthenocissus tricuspidata are used for local coverage (avoiding full coverage, regardless of beauty and ugliness) to increase the lively atmosphere.
3). The plants on the water surface are arranged neatly. The water landscape is lower than people's sight and echoes the waterside landscape, and the reflection in the water is the most suitable for viewing. Plants in the water are matched with lotus flowers to reflect the artistic conception of "lotus leaves are infinitely bright in the sky, and lotus flowers have different colors when reflecting sunlight". However, if there are pavilions, terraces, buildings, pavilions, towers and other garden buildings on the shore, or when designing beautiful and colorful flowers and foliage trees, the plant configuration in the water should not be congested, and enough empty water surface should be left to show the reflection.
4). Dike Island Plant Configuration Setting up Dike Islands in water is the main means to divide the water space, and the Dike Islands are often connected by bridges. The arrangement of plants on the dike island not only increases the level of water space, but also enriches the color of water space, and the reflection becomes the main landscape. There are many types and sizes of islands. Around the island, willows are the main plants, and arborvitae, acacia, wisteria, crape myrtle and other trees and shrubs are planted alternately, which is dense and orderly, increasing the level and has a good guiding role. In addition, a pool of clear water can be used to expand space, break the closed environment and create a natural and lively landscape. For example, small waterscape gardens can be built in some scenic spots in parks, gardens in residential areas, roof gardens, flower gardens in exhibition greenhouses, gardens in large hotels and other places. Work with aquatic plants to create a clear pool and a full moon.
3. What are the characteristics of the urban environment?
Urban environment: a highly artificial living environment created by human beings using and transforming the environment.
The city has modern industry, architecture, transportation, transportation, communication, cultural and entertainment facilities and other service industries, which has created superior conditions for residents' material and civilized life. However, the dense population, numerous factories and traffic jams in cities have caused serious pollution and damage to the environment.
Urban environment is the sum of human and natural conditions that are interrelated with the whole city. Including social bad environment and natural environment. The former consists of basic elements such as economy, politics, culture, history, population, nationality and behavior. The latter includes geology, geomorphology, hydrology, climate, animals and plants, soil and other elements. On the one hand, the formation, development and layout of cities benefit from urban environmental conditions, on the other hand, they are also restricted by local environment. The unreasonable development and excessive expansion of cities will lead to the deterioration of regional environment and urban internal environment. The quality of urban environment directly affects the production and life activities of urban residents. It is also one of the main contents of urban geography and urban planning.
4. What are the main ways for garden tree species to adapt to the site and trees?
The meaning of a suitable tree is:
1) Selecting tree species to adapt to the local environment and climate, that is, planting trees under suitable environmental conditions, is the embodiment of the principle of selecting tree species according to local conditions, and adapting trees to the site is the basic principle of planting plants in landscaping.
2) Choosing native tree species to grow healthily and giving full play to the role of trees is an important principle of garden planting.
Ways to adapt the site to the tree:
(1) Select tree species suitable for a certain site condition (survival+comprehensive function+market).
(2) Transformation (tree adaptation and tree adaptation)
A. Adapting trees to the right place: transforming some characteristics of tree species through seed selection, introduction and domestication, and breeding.
B. Improving the land for tree planting: measures such as soil replacement, fertilization, irrigation, temperature and land management-changing the growing environment. Such as: greening under the overpass, ten contributions, octagonal gold plate, ivy, peach leaf coral, france holly (coral tree)
5. How to establish mixed tree species?
Cold temperate coniferous forest and temperate coniferous and broad-leaved mixed forest. It is an extension of the coniferous forest belt in the north of the world to the south, mainly distributed in the mountainous and hilly areas in the north of Daxing 'anling. This is the northernmost forest area in China. The terrain in this area is small, the slope is gentle, the top of the mountain is round, the altitude is about 1 100 m, the soil layer thickness is uneven, and there is an island permafrost layer. The forest coverage rate is 53.6%, the annual average temperature is below 0℃, and the annual rainfall is 350~500mm. The rainfall period is mainly concentrated in July and August when plants grow. The characteristics of this area are as follows: Larix gmelinii is the dominant tree species in the forest, accounting for 70% of the forest area; Followed by birch forest and Pinus sylvestris var. mongolica forest. Quercus mongolica forest and a small number of Quercus mongolica forest, Populus davidiana forest and Picea koraiensis forest are secondary forests formed after larch destruction. Most of the tree species constitute a single-layer pure forest, with simple structure, underdeveloped plants outside the layer, and many temperate forest plants, such as Schisandra chinensis, Stichopus japonicus and Acer.
Gradually transition to the temperate coniferous and broad-leaved mixed forest belt to the south. The forests in Xiaoxing 'anling and Changbai Mountain are typical coniferous and broad-leaved mixed forests with rich forest species. The elevation of most mountainous areas is below 1000m; The annual rainfall is 600 ~ 1000mm, decreasing from Changbai Mountain to the north. This is the largest forest area in China, with dense forests. There are many pure coniferous forests in the middle and high mountains of Changbai Mountain (1000 ~ 1800 m). In addition to Korean pine, the main conifers are Picea koraiensis, Abies, Picea, etc. Most of them are coniferous and broad-leaved mixed forests. The mixed broad-leaved trees include Betula platyphylla, Populus liaotungensis, Ulmus chunensis, Ulmus pumila, Quercus mongolica, Tilia amurensis, Fraxinus mandshurica, Bo Huang radish, Betula platyphylla, Juglans mandshurica, Acer negundo, Populus davidiana and so on. After the coniferous and broad-leaved mixed forest is cut, it usually forms a secondary broad-leaved mixed forest dominated by oak forest, Populus davidiana forest and birch forest. Korean pine broad-leaved forest is concentrated in Xiaoxing 'anling, which is a representative type of this area.
Northeast Forest Region: The most important natural forest region in China at present, with an existing forest area of 30.94 million hectares, accounting for 26.9% of the country; The forest stock is 2.89 billion cubic meters, accounting for 32% of the country; The forest coverage rate is about 37.6%, mainly coniferous forest and mixed coniferous and broad-leaved forest. After cutting, regeneration and artificial transformation, the proportion of artificial forests has gradually increased. Daxinganling in northwest China is mainly Larix gmelinii forest, birch forest and Populus davidiana secondary forest. Xiaoxing 'anling is mainly Korean pine forest and mixed coniferous and broadleaved forest, with many tree species, such as Korean pine, larch, spruce, fir, linden, Fraxinus mandshurica and birch. The forest in Changbai Mountain area is similar to Xiaoxing 'an Mountains, but there are more broad-leaved trees, Sha Song and Pinus sylvestris var. mongolica. Changbai appears.
Southwest: Located in the southeast of Qinghai-Tibet Plateau, it is mainly composed of alpine coniferous forest and coniferous and broad-leaved mixed forest. The height difference in this area is very large, and the forests are mostly distributed in the middle and lower part of the hillside below 4000 meters above sea level. The forest area is 22.45 million hectares, accounting for 19.5% of the whole country. The forest stock is 3.58 billion cubic meters, accounting for 39.7% of the country; The wood coverage rate is 28.3%. The main tree species are fir, spruce, larch, alpine pine, birch and alpine oak. There are many rare animals living in the forest area, such as giant pandas, golden monkeys and pronghorn.
Southeast forest region: China's southeast mountainous region is vast, with good climatic conditions and great potential for forestry production, which is suitable for vigorously developing timber forests, bamboo forests and various economic trees. The proportion of artificial forest and economic forest in forest area is significant. The main tree species are Pinus massoniana, Pinus taiwanensis, Cunninghamia lanceolata, Cryptomeria fortunei, various bamboos (such as Phyllostachys pubescens, Phyllostachys pubescens, Phyllostachys pubescens) and various evergreen broad-leaved trees (such as Cinnamomum camphora, Phoebe bournei, Quercus acutissima, Quercus microphylla, Zelkova schneideriana, etc.). ) and various oak species (such as Quercus variabilis, Quercus acutissima and Quercus microphylla). The main economic forest species are camellia oleifera, tung oil tree, Ubuntu, lacquer tree and palm tree.