繁殖棉黄萎病菌培养料的改进

为了选育抗黄萎病的棉花品种,必须具有病圃人工繁殖黄萎病菌。过去惯用棉籽;但是黄萎病菌在棉籽上生长较慢,容易感染杂菌。为了改进这一问题,我们借鉴啤酒制造业用玉米代替大麦的经验,从1980年开始,多次用玉米糁等培养料试验比较。四种     

转基因棉籽培养料对平菇厉眼菌蚊的影响及相关因子分析

测定表明,转基因棉中30棉籽培养料中平菇厉眼菌蚊的死亡率均高于普通棉中16,20%棉籽含量时差异显著;转双价基因棉SGK321棉籽培养料上的死亡率略高于普通棉石远321,但差异不显著。用ELISA检出平菇厉眼菌蚊体内含有Bt蛋白,36 h后Bt蛋白降解到检测底限。转基因棉籽对平菇厉眼菌蚊的生长有抑制作用;普通棉中36棉籽配制的培养料在3%棉籽含量时,对平菇厉眼菌蚊有显著的抑制作用,显然,除了Bt蛋白外,培养料中还有其他因素在起作用。和普通棉中16棉籽相比,转基因棉中30棉籽总黄酮含量高出其约一倍,棉酚含量高76.92%,单宁含量高66.40%;转基因棉中30配制的培养料中,幼虫死亡率高于其亲本对照棉,差异显著。比较普通棉石远321,转基因棉SGK321棉籽总黄酮含量、棉酚含量和单宁含量均有所降低;转基因棉SGK321配制的培养料中,幼虫死亡率高于其亲本对照棉,差异不显著。     

利用汤普森多毛菌防治柑桔锈壁虱试验

汤普森多毛菌(Hirsutella thompsonii)是天然抑制多种植食性螨类的主要菌类;能侵染多种瘿螨,为柑桔锈壁虱(Phyllocoptes oleivorus Aahmead)的重要寄生性真菌。该菌自1950年美国人Fisher鉴定以后,30余年来,世界上已有10余个国家、地区先后发现该菌的分布,并正在开发利用。1972年浙江柑桔所从台州一个桔园内分离到该菌株,进行了研究     

棉花黄萎病种籽带菌检验

黄萎病菌生长缓慢,使用普通方法作带菌分析,常因镰刀菌茂密生长而不易看到,仇元等的种子检验法操作程序复杂,我们在现有方法的基础上,进行了一些探索。由于病原菌能以棉籽上生活,如果具备一定温湿度,利用种子内的养分使其生长估计有一定的可能性。据此我们设计了用流水直接冲洗棉籽、湿室进行培养的方法。试验方法:1963年4月22日取1962年在当地采得的黄萎病株种籽50粒,放入500毫升三角瓶中,瓶口用纱布罩紧,流水(系用本所自流井)冲洗24小时后,放入无菌室内,再用灭菌水振洗三次,以备接种。     

进口棉短绒中棉花枯黄萎病菌检测研究

棉花枯、黄萎病是棉花生产中最重要的病害,主要依靠土壤和种子调运进行远距离传播。近年来,由阿拉山口口岸进口棉短绒量不断增加,2008年口岸进口棉短绒货量为3.8153947万t,大部分棉短绒都含有大量的棉籽,可能携带棉花枯萎病菌(Fusarium oxysporum Schl.f.sp.vasinfectum(Atk.)Snyder&Hansen)和棉花黄萎病菌(Verticillium dahliaeK leb)。为保护新疆及我国棉花产业安全,防止棉花枯、黄萎病菌随进口棉短绒中棉籽传入,对进口棉短绒中棉籽是否携带棉花枯黄萎病菌进行了检验。结果,只在进口棉短绒中棉籽上检测到棉花枯萎病病原菌尖孢镰刀菌(Fusarium oxysporum Schl.f.sp.vasinfectum(Atk.)Snyder & Hansen),未检出棉花黄萎病菌。     

顶斑筒天牛的研究

頂斑筒天牛是梨、苹果、沙果、李、桃等的钻蛀性害虫,幼虫蛀食当年生新梢和二年生小枝,致使枯死。一年发生一代,以末龄幼虫在被害枝內越冬,4月中下旬至5月下旬变蛹,5月上中旬至6月上旬羽化。幼虫的孵化期,始于6月上中旬,終于7月中旬。根据各期习性观察,提出冬季結合整枝,剪除被害虫枝;在幼虫初孵期間,經常检查剪去虫害枯枝;选育质优产高的短枝型品种以及注意果苗检疫等一系列措施,在实施地区,已收到較好效果。     

受寄主调节的病原物基因型互作

将大麦白粉菌(Erysiphe graminis f.sp.hordei)的毒性和无毒性分离菌接接种顺序接种于具有不同抗性基因的大麦品种。不亲和反应所诱导的抗性能降低毒性分离菌的侵染,相反亲和反应诱导的感病性其程度足以增加无毒性分离菌侵染抗性寄主的能力。互作的净效应与单由某一种毒性分离菌接种相比能减少分生孢子的产生最。分离菌之间的每一个互作取决于所采用的寄主品种、病原分离菌和接种次序。先接种无毒性分离菌再接种毒性分离菌常常最易观察到诱导抗性。若先按种毒性分离菌,诱导感病性常常更加明显。不过,在品种Wing上先接种无毒性分离菌,诱导感病性更加明显。在品种Hassan上,先接种毒性分离菌,虽常诱导感病性,但某些时候以先接种无毒性分离菌时诱导更强的感病性。在后一种情况下,尽管无毒性分离菌所致侵染相对较少,但所产生的孢子大多数是由无毒性分离菌形成的。某些事证表明,无毒性分离菌可获得侵染不亲和性寄主的能力。如果没有毒性分离菌的存在,经过几个世代以后这种作用就会消失。     

蓖麻常见病虫害的防治

1　蓖麻枯萎病　　蓖麻枯萎病 Fusarium oxysporium Schlecht f.sp.ricini( Wr.) Gordon是蓖麻最严重的病害之一 ,其病原菌为半知菌类尖孢镰刀菌。蓖麻苗期发病常全部毁灭 ,成株期发病也往往成片枯死。病原菌除危害蓖麻外 ,还危害黄瓜、辣椒、豌豆、蚕豆、菠菜、胡萝卜、麻类等多种作物。1 .1　蓖麻枯萎病症状　　蓖麻从苗期到成株期 (直至花蕾期 )均能发病。苗期多从根部和茎基部开始发病 ,然后发展到整个茎部和叶柄、叶片。根部受害 ,初时只有少数变褐色 ,后来大部或全部变黑腐烂 ;茎基部和茎部的病斑初为水渍状 ,后纵向凹陷 ,暗褐色或…     

棉红铃虫为害棉籽损失考查

红铃虫为害棉籽后,造成虫蛀籽,导致棉籽重量减轻,品质下降,棉籽含油率显著降低.棉籽损失也是红铃虫为害损失的一部份,但由于棉籽收购价格低,且棉籽油不常为食用,所以在估量红铃虫损失时,常不计算在内。然而,由于棉籽中含有十分丰富的蛋白质和氨基酸、棉籽壳和短绒等都具有重要的利用价值,是廉价的工业原料,有待于开发和利用。1983年在协作组的安排和县糠醛厂的协助下,我们进行了有关红铃虫为害棉籽的损失测定,测定结     

棉籽携带棉铃疫菌及该菌的致死温时

冬季用显微镜镜检患有疫病的棉铃种籽，能检查到棉铃疫菌的游动孢子囊或卵孢子；重病棉铃种籽所带的卵孢子比轻病棉铃种籽多。疫病占整铃面积１／４以上时，其中的种籽可分离到疫菌；疫病在铃面的面积较小时，在其种籽上未分离到疫菌。将疫病棉铃中的自然带病种籽、健铃种籽与疫菌混合，或土中接种疫菌后播种，都能在铃期表现烂铃，烂铃数比播种健铃种籽多；但８月少雨时，种籽带菌对铃期烂铃影响不明显。疫菌在５５℃５分钟即死亡；     

Influence of after-ripening environments on the germination characteristics and seed fate of Italian ryegrass (Lolium multiflorum)

Italian ryegrass ( Lolium multiflorum Lam.) is an exotic winter annual weed that recently has seriously infested wheat fields in central Japan. To understand the influence of tillage systems on the germination ecology and seedbank dynamics of naturalized Italian ryegrass, we compared the fate of the seeds that were after-ripened in the soil with that of the seeds on the soil surface, and then examined the germination characteristics of the seeds retrieved from both treatments by germination tests in both a light/dark (12 h photoperiod) condition and in constant darkness. The seedling emergence was greater initially for the seeds after-ripened on the soil surface than for the seeds in the soil. The component of emergent seeds after-ripened on the soil surface increased as time passed during the summer, whereas that of emergent seeds in the soil scarcely increased. This contrasting emergence was, in part, attributable to the ability of the seeds to germinate at higher temperatures in the light/dark condition than in constant darkness. These results suggest that untilled systems, which leave many seeds on the soil surface, might promote the rapid depletion of Italian ryegrass seeds through germination before wheat sowing in early winter. In contrast, seed burial by tillage might inhibit the germination of the seeds and form a large transient seed bank available to germinate during the wheat-growing season.     

Digitaria ciliaris seed banks in untilled and tilled soybean fields

We gained an understanding of the vertical distribution and seasonal dynamics of Digitaria ciliaris (Retz.) Koeler seed banks in untilled and tilled soybean fields using studies on naturally established seed banks and on seeds stored in the field. In untilled fields, D. ciliaris seeds were highly concentrated on or near the soil surface from late autumn to spring, whereas only a few seeds were found on the soil surface in the following summer. One year after tillage, there was a high concentration of the seeds on the soil surface. In the tilled fields, seeds were distributed uniformly throughout the soil profile and were present all year long, with only a few seeds found in the following summer. A study of seeds that were artificially buried or stored on the soil surface verified that D. ciliaris seeds were extremely short-lived in the field and could not form a large, persistent seed bank, even when the seeds were buried by tillage. Tillage contributes to suppression of D. ciliaris seedling emergence by reducing the number of seeds that are on or near the soil surface. Furthermore, D. ciliaris seeds showed a greater need for light in order to germinate throughout the year, even when they were stored on the soil surface. Particularly, light was critical for germination during summer. The light requirement for germination should be one reason why viable D. ciliaris seeds on the soil surface are carried over into the next season in untilled fields.     

真空熏蒸对种子发芽的影响

利用ZXX-65真空循环熏蒸设备对23种蔬菜、花卉和林木种子进行了真空熏蒸实验.结果表明,真空熏蒸(5000Pa)对种子的发芽率影响较小;一些种子的发芽期产生提前或推后,但幅度很小(1～2d);发芽后幼苗均生长正常.在满足除害处理要求的前提下,真空熏蒸对种子基本不会产生药害,可以用于种子检疫除害快速处理.     

Behaviour of hard and permeable seeds of Abutilon theophrasti Medic. (velvetleaf)

Experiments were carried out on seeds of Abutilon theophrasti (velvetleaf) to examine the germination behaviour of hard (impermeable) and soft (permeable) seeds and to test various physical and chemical treatments against hardseededness. There was no evidence, in fresh or in old seeds, of leachable germination inhibitors or of leachable compounds affecting hardseededness. Marked differences were found between hard and soft seeds in respiration and leakage. Oxygen uptake was negligible in hard seeds. A rapid efflux of K⁺ ions from hard and soft seeds was detected during the first minutes of immersion. Subsequently, the rate of leakage of hard seeds decreased markedly. After 4 h of imbibition, conductivity measurements differentiated individual hard and soft seeds. Abrasion, percussion and immersion in sodium hypochlorite had no effect on hard seeds, but mechanical scarification and immersion in sulphuric acid reduced hardseededness. Gamma radiation did not affect the hard coat but damaged the embryo. A. theophrasti seeds were exposed to organic solvents such as acetone. ethanol and methanol, and to pesticides such as butylate, EPTC, metham-sodium, vernolate and methyl bromide, in liquid or gaseous phase. Some of the treatments reduced germination of soft seeds, but none, even methyl bromide, had any significant effect on the number or viability of hard seeds, proving their complete impermeability.     

Aerial seed germination and morphological characteristics of juvenile seedlings in Commelina benghalensis L.

Seed germination, seedling emergence, and the morphological characteristics of juvenile seedlings of Commelina benghalensis L. were observed. For aerial seeds collected in September and October, seedling emergence peaked in April and June for large seeds and from June to August for small seeds, whereas seedling emergence for large seeds collected in November showed peaks in March and April under natural rainfall conditions, and in April and June under irrigation conditions. Seedlings from small seeds emerged intermittently over a longer period from April to August under both conditions. Aerial seeds of C. benghalensis germinated on wet filter paper on the second day after seeding (DAS) for large seeds and the fourth DAS for small seeds. The germination percentage for large seeds was higher than that for small seeds by the 14th DAS. The germination percentage for large aerial seeds showed no significant difference between light and dark conditions. However, the percentage for small aerial seeds was higher under light than under dark conditions. Seedlings from large aerial seeds emerged on the third DAS at 0–50 mm soil depths. The percentage of emergence at 0 and 1 mm soil depths increased until the 30th DAS, whereas those at soil depths of 5–50 mm showed no change after the 9th DAS. There was no emergence at a soil depth of 100 mm. Seedlings from small aerial seeds emerged on the 6th DAS at 0–1 mm soil depths, with the percentage increasing until the 30th DAS. Although seedlings at 5 and 10 mm soil depths also emerged on the 6th DAS, there was no change in the percentage after the 12th DAS. There was no emergence at soil depths of 20–100 mm. The hypocotyl and taenia (part of the cotyledon connected to the seed) in juvenile seedlings that emerged from soil depths of 50 mm were longer than those in seedlings emerging from a soil depth of 1 mm.     

Retention and distribution of dry powder and liquid formulations of insecticides and fungicides on commercially dressed cereal seed

Analysis of samples of seeds, mostly wheat, treated commercially with insecticides and fungicides showed that many carried much less than the theoretical dose, some less than one-tenth. The average loadings of seeds treated with dry powder formulations were nearly always small, but the distribution of insecticide between seeds was fairly uniform. The average loading of seeds treated with liquid formulations was closer to the target, but the distribution was irregular, most of the seeds carrying little insecticide and a few seeds amounts large enough to be phytotoxic. Insecticides applied as dry powders do not adhere strongly to the seeds, but they remain in association with seeds contained and carried in bags. Applied as liquids, insecticides are difficult to remove from seeds. The ratio of insecticide to fungicide on seeds dressed with powders containing both usually resembled the ratio in the original powder. With liquid seed dressings of insecticide and fungicide applied separately in different formulations, the ratio of insecticide to fungicide often differed widely from the theoretical. The average loading of fungicide was close to the target, but the average amount of insecticide was often much less. With either wet or dry dressings, the amount of pesticide on seeds was consistently greater from some merchants than from others. This was independent of the machinery used. Loadings were not consistently affected by type of seed-dressing machinery or formulation, stage of operation, weather or variety of seed.     

东北稻区稻田杂草稻控制措施的探讨

东北稻区自生杂草稻在目前常用的稻田除草剂常规剂量处理下株防效为0,种子埋深10 cm以下才能控制其萌发出土,灌水深度10 cm对种子发芽没有明显的抑制作用.在秋季灌水条件下越冬的种子冻死率为100％,而在干燥态土壤中多数种子可安全越冬.     

The Relationship Between Wheat Seed Weight, Infection by Fusarium culmorum or Microdochium nivale, Germination and Seedling Disease

The distribution of seeds by weight for three lots of winter wheat cv. Avalon infected by Fusarium culmorum and three lots of winter wheat cv. Riband infected by Microdochium nivale was determined. The distribution of infected seeds within each seed lot was then determined by isolating F. culmorum from seeds on moist filter paper and M. nivale from seeds on potato dextrose agar. The distribution of M. nivale infected seeds between seeds of different weight was similar to that of the seed lot as a whole, whereas the distribution of F. culmorum was greater in light seeds than heavy seeds. The percentage germination of infected seeds decreased with seed weight. A similar situation was found with respect to seedling emergence in compost for F. culmorum infected seeds. However, with M. nivale infection, similar numbers of seedlings emerged from both light and heavy infected seeds. Seed treatment with guazatine increased seedling emergence for both light and heavy seed infected by M. nivale. However, seedling emergence from F. culmorum infected seed was poor even following treatment with guazatine. Poor emergence was most evident from light seed.     

SEED GERMINATION OF AGROSTIS GIGANTEA ROTH

Summary. To assess the role of seed production and seedling behaviour in the biology of the perennial grass weed Agrostis gigantea Roth, seed germination and seedling emergence of the species were investigated in the glasshouse and in the laboratory. These studies showed that the species may produce a large number of seeds: panicles collected from a cereal field in 1971 and 1972 contained about a thousand viable seeds in both years. Mature seeds of the species are mostly non-dormant and germinate readily on moist soil surfaces. Freshly-harvested seeds require light and alternating tempratures for germination, but older seeds can germinate in constant temparature in the dark. Covering seeds with 0·6 cm soil halved the percentage emergence and few seedlings emerged from seeds sown deeper than 3±8 cm, but many seeds survived under enforced dormancy. A. gigantea seeds may also persist long in frequently cultivated shallow soil. The species flowers late but its seeds become viable quickly—in 1969 a third of the number that were finally viable became so within a week of flowering.
Germination des semenes d' Agrostis gigantean Roth.     

Evolution de l'aptitude à germer des graines d'Amaranthus retroflexus L. récoltées dans différentes conditions, au cours de leur conservation

Development during storage of germinability of seeds of Amaranthus retroflexus L. harvested under different conditions The effect was studied of dry storage at 20 ± 1°C for 6 months or in soil 15 cm below the surface during one winter, on the germination behaviour of seeds of Amaranthus retroflexus L. harvested at the level of the main inflorescence on the parent plants grown under natural conditions or in different conditions of controlled photoperiod or temperature. At harvest, the seeds from plants which had developed late (July) in natural conditions were less dormant than those from plants appearing earlier (April); in controlled conditions, plants grown at 20°C in long days (16 h) produced seeds more dormant than those harvested from plants grown either at 20°C in short days (8 h) or at 25°C in long days (16 h). After dry storage or in the soil, this variation in germinability decreased but was never totally suppressed; the seeds retained the characteristics acquired during their formation and maturation. At harvest, for a defined growing condition, the dormancy of the seeds produced depends on the physiological state of the parent plants; after storage, the seeds which were the most dormant at harvest germinated more than the less dormant seeds. Finally, burying has a more favourable effect on breaking dormancy of the seeds than has dry storage.