What is the relationship between orchid variation and plant viruses?

Plant virus infectionorchidseffectsorchidsgrowth.OrchidsOrchid plants show various manifestations in response to virus attack, and morphological variation occurs. Some variations, such as dwarfing, various types of yellowing (white stripes, spots) at flowering, toothed leaves, deformities of the floral organs, and variation in flower color, can increase theorchid'sornamental value, and are what orchid fanciers dream of. I. Known orchid viruses According to reports, the plant viruses that infect orchids (including Eupatorium) at home and abroad are:Cymbidium ensifoliummosaic virus,Cymbidium ensifoliumring spot virus,Cymbidium ensifoliummild mosaic virus, Cymbidium ringspot virus, orchid spotted virus, Vanda mosaic virus, Dendrobium mosaic virus, tomato ring spot virus, cucumber mosaic virus, etc. A mentor once told me that he had seen a report that the rhabdovirus of rice yellow dwarf disease can infect orchids. II. Manifestations of virus infection inorchids "Leaf-art orchids": appropriately increasing light, controlling water, and raising the cultivation temperature can make the "variegation" more obvious. This is the experience of some orchid fanciers, and it is also circumstantial evidence indicating that variegated orchids may be formed by virus infection. Of course, the existence of the phenomenon of "leaf art" formed by chromosome changes caused by chemicals or radiation stimulation cannot be ruled out here. The symptoms after orchid plants are infected by viruses include: 1. Yellowing virus: The golden edges of leaf-art orchids. Variegation and spots may all be related to the yellowing virus. For example, "late manifestation" means that in the early stage no lines or spots appear, or they are not obvious, and only later do the lines or spots appear. This is because in the early stage the temperature is lower and the virus does not grow as fast as the plant. In the later stage the plant's growth rate slows down, and relatively speaking the virus increases more, so the plant shows symptoms of virus attack, and yellow or white lines or patches appear on the leaf surface. Golden and silvery "edges", "variegation", and "spots" may, depending on the season and year, appear on some new shoots and not on others, be good on some and poor on others, be present in some years and absent in others. There is also the phenomenon of reappearing after a year. Sometimes "gold turns to silver", that is, golden-yellow lines and patches can turn white; the reason for this should also be related to an increase in the amount of virus in the leaf tissues. 2. The "Damo" phenomenon. Damo is a rare and valuable variety of Cymbidium sinense that was all the rage in Taiwan, China and Hong Kong, China for a time. Damo has various types of leaf and flower changes, which is its special charm. From "green base board" Damo seedlings to cultivating them into famous Damo varieties with various types of leafand flowerchanges requires conditions and skill. A Taiwanese orchid friend once said he had this skill. In Chengdu we also saw green base board Damo seedlings that had been bought for tens of thousands of yuan and then returned because they did not produce art. Cultivating Damo green base boards until they produce art belongs to the "late manifestation" category, and should be the course of the disease when viral disease shows symptoms. The technique may be condition-control methods such as increasing temperature and controlling nutrition. The plant virus causing the yellowing and "art production" of Damo sect (Cymbidium sinense) is very likely the rhabdovirus pathogen of rice yellow dwarf disease. This type of virus can be transmitted by insect vectors such as leafhoppers. Plants are systemically virus-carrying, without. Note that propagation (division) can spread it. But seeds cannot transmit the virus. 3. Dwarfing virus: The various dwarf plant groups appearing in some orchid species have opened a new field for orchid appreciation, and dwarf types sometimes also produce strange flowers. Most such dwarf types should be related to plant dwarfing viruses. Dwarf Cymbidium sinense also has "xinglong", that is, the leaf surface often has longitudinal raised dark stripes, which is consistent with the deformities caused by virus infection. 4. Toothed leaf virus: At present, "crystal" among leaf-art orchids is highly valued. Toothed edges are very rarely seen. "Crystal" refers to the tip of the orchid leaf appearing transparent. This phenomenon is similar to the toothed leaf phenomenon caused by the toothed leaf virus, and should be related to plant viruses. 5. Deformity of flowers The formation of lotus-petal, plum-petal, narcissus-petal and other petal-type flowers, as well as chrysanthemum-petal (multi-petal), few-petal, butterfly flowers, and plain-heart strange flowers, may all be related to orchid viruses. Japanese orchid fanciers once affirmed that deformed flowers are related to high temperature. Strange flowers and rare plants are often found in areas with frequent human activity, while orchids from remote deep mountains and old forests with few human traces rarely produce strange varieties. In plum-petal and narcissus-petal flowers, the tips of the petals appear anther-like; in butterfly-petal flowers, the sepals or petals appear lip-like; both belong to deformed flowers along with multi-petal and few-petal forms. Plain-heart orchids evolved from ordinary orchids; Professor Yan Chujiang once did research on this. They should also be abnormal-color flowers. Abnormal-color flowers and deformed flowers often have rich colors in flower color and are especially loved by people. They are related to virus infection. Under changed conditions of temperature, light, fertilizer, water, and other horticultural traits, some changes may appear. 6. Instability of traits Becausecultivationconditions differ, the flower shape and flower color that bloom vary greatly, and this also includes some traditional famous flowers. For example, Ningmei also includes plain-heart ones, and on one scape there are flowers of different forms, such as "Shiyangjin". 7. Weakening of vitality. According to information,Cymbidium goeringiithe famous lotus-petal variety Luyun was formerly very rare. The reason is that when one new shoot grows, basically one old shoot dies, making it very difficult to propagate. It shows the weak vitality of the variety. Moreover, Luyun leaves also produce multi-petal flowers. III. Misjudgment, use, and utilization of orchid viral diseases. The diagnosis of plant viral diseases should be determined by combining methods such as electron microscopy, serum testing and identification, and artificial inoculation. However, in view of the high price of various orchids and the time-consuming and laborious identification procedures, apart from some work done and some results obtained by relevant departments, efforts are still needed to clarify the effects of all types of orchid viruses. How can we preliminarily determine whether an orchid has been attacked by a virus? 1. Under the samecultivationconditions, when a plant or orchid is seen to differ in morphology and color from ordinary orchid plants and orchids, after excluding damage caused by insect pests and fungal and bacterial diseases, it may be considered the result of virus infection, because the chance of gene changes altering plant traits is very small, while the possibility of virus infection is quite large. 2. If changes in orchid plant and orchid traits increase ornamental value, we should try to increase the degree of their change. If the trait changes are caused by virus infection, we can regulate temperature, nutrition, water, and light based on the principle that the growth rate of the orchid plant is controlled while virus multiplication remains unchanged. This should be the key to improving the grade of most leaf-art and flower-art orchids. 3. Those with the conditions can clarify the mechanism by which the traits of rare and valuable orchids are formed. If it is confirmed to be caused by virus infection, then artificial or vector inoculation methods can be used to make ordinary orchid varieties richer and more colorful. Excerpted from "Flower World Express" by Wang Guoxing