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鑑别寄主接种和抗血清沉淀试验、防虫栽培试验以及病毒干扰作用试验都证明未退化的马铃薯“男爵”品种的种薯中已经普遍存在着x和y两种花叶病毒。休眠期及发芽期的高温处理显著降低种薯中的x-病毒浓度,但是当处理停止后回到正常的貯藏或催芽的温度条件下的时候,浓度又升到未经高温处理的对照的水平。经过高温处理的退化种薯长出皺缩花叶症状特别严重和块莖产量大大降低的植株。对于含有病毒而未退化种薯的同样处理的后果远不如此显著。土壤温度对于新形成块莖的病毒抵抗力的作用显然是马铃薯退化的决定性环节。在高海拔地区和在秋播的气候条件下形成的块莖含有显著较少的x-病毒。种薯的病毒浓度与下一代植株的症状是正相关的。但是,漫有发现叶片中x-病毒浓度与生态条件相联系的规律性差异。从1956年以来,曾经利用特别设计的土壤条件调节床进行自然感染病毒的未退化种薯和实生苗后代无病毒种薯的栽培试验。调节床建在具有滑动玻璃顶棚的防虫铜纱室内,使植株地上部暴露于北京的一般温湿度条件下。在25℃恆定土壤温度条件下,两种种薯长出的植栋当代都没有症状,而所形成的新块莖不但产量很低而且都是畸形的并提早发芽。在下一代,无病毒的产生细弱的幼苗,但无任何花叶症状,而自然感染病毒的则产生94.4%具有皺缩花叶症状的植株。在15℃恆定土壤温度下自然感染病毒种薯所形成的新块莖在下一代产生了19.4%花叶植株。接种病毒的实生苗后代植株当代就表现出典型症状。高土温显著加重了症状程度,在下一代士温影响所引起的差异尤为突出。x和y两种病毒的混合接种不但使植株发生最严重的症状,而且使x-病毒在体内达到最高的浓度。盆栽的无病毒马铃薯植株接种前的35℃高温三天处理促进了接种的x-病毒在叶内的数量累积和植株的症状表现。同样处理不影响烟草对于同一病毒的反应。显然,马铃薯在良好的环境条件下具有对于已经侵染到其体内的花叶病毒的抵抗力。这可以表现于抗病毒繁殖上、抗病毒变异上或抗病毒损害上。究竟每一类型的抵抗力对于x和y两种病毒各起多大作用还有待于进一步研究。
Identification of host inoculation and antiserum precipitation tests, pest-resistant cultivation tests and virus interference tests all demonstrated that both x and y mosaic viruses were prevalent in the seed of the “baron” potato varieties that did not degenerate. High temperature treatments during dormancy and germination significantly reduced the x-virus concentration in the seed tubers, but again returned to normal storage or sprouting temperature conditions after treatment was stopped, again to the level of the non-hyperthermal control . Degraded seedlings that have been subjected to high temperature treatment have plants that exhibit particularly pronounced symptoms of wrinkled mosaic leaves and significantly reduced tuber yield. The consequences of the same treatment for viruses that are not degenerate are far less pronounced. The effect of soil temperature on the virulence of newly formed tubers is clearly a decisive factor in potato degradation. Tubers formed at high altitudes and in autumn seasons contain significantly less x-virus. The virus concentration of seed potato is positively correlated with the symptoms of the next generation of plants. However, the regular differences in the correlation between x-virus concentration and ecological conditions in the leaves were found. Since 1956, specially designed soil condition conditioning beds have been used for the cultivation of virus-free seedlings of naturally-infected viruses and seedless offspring of seedlings. The conditioning bed was built in a pest resistant copper gauze with sliding glass ceiling, exposing plant shoots to normal temperature and humidity conditions in Beijing. At constant soil temperature of 25 ° C, the seedlings of both seed potatoes are contemporary without symptoms and the new tubers formed are not only low in yield but also deform and prematurely germinate. In the next generation, virus-free seedlings were produced faintly but without any mosaic symptoms, while naturally infected viruses produced 94.4% of plants with wrinkled mosaic symptoms. The new tubers formed by naturally infected virus seed plants at a constant soil temperature of 15 ° C produced 19.4% of the mosaic plants in the next generation. Progeny plants vaccinated with virus show typical symptoms in the contemporary era. High soil temperature significantly aggravate the degree of symptoms, especially in the next generation caused by temperature differences. Inoculation of both x and y viruses not only causes the most severe symptoms in the plant, but also maximizes x-virus in the body. Potted virus-free potato plants before inoculation at 35 ° C for three days promoted the accumulation of inoculated x-virus and the symptom appearance of the plants. The same treatment does not affect the response of tobacco to the same virus. Obviously, the potato has good resistance to the mosaic virus that has invaded its body under good environmental conditions. This can be manifested in antiviral multiplication, antiviral variation, or antiviral damage. Whether or not each type of resistance plays a role in both the x and y viruses remains to be further studied.