种皮和环境温度对橡胶树种子萌发的影响

在人工气候箱控制的条件下,研究了种皮和环境温度对橡胶树(Hevea brasiliensis)种子萌发的影响.结果表明,种皮对橡胶树种子的吸水和萌发具有明显的机械限制作用;去除种皮后种子萌发速率加快,萌发指数增大,但萌发率从83.8%下降到47.8%,幼苗活力指数从332.3下降到187.9.15℃以下的温度明显推迟种子萌发,且萌发率下降.去除种皮后的种仁萌发率、萌发指数和幼苗活力指数均随着温度的升高而增大;有种皮种子的萌发率、萌发指数和幼苗活力指数分别在20℃(94.7%)、30℃(1.86)和25℃(374.4)时最大,而萌发速率系数随着温度的升高先增大后减小.在橡胶树栽培和胶园建设中,可利用种皮对种仁水分散失的限制作用以及对低温的不敏感性,有效延长橡胶树种子的贮藏时间,提高萌发率和籽苗质量.     

‘勐海大叶茶’种子萌发特性

以大叶茶品种‘勐海大叶茶’ （Camellia sinensis var. assamica cv. Menghai Dayecha） 种子为材料,进行种子萌发特性的初步研究。研究发现,种皮对‘勐海大叶茶’种子的萌发存在一定的作用,含水量较高时,人为破除种皮有助于种子的萌发,随着含水量的降低,人为破除种皮反而降低了种子的萌发率。‘勐海大叶茶’种子的最适萌发温度为30℃,15℃以下时萌发率较低,容易发生低温伤害,变温处理对提高种子萌发率的效果不明显。基质对大叶茶种子萌发的影响不明显,四种不同种植基质条件下,种子的萌发率趋于相同水平,证明基质类型并非影响种子萌发的关键因子。     

顽拗性竹柏种子的贮藏特性?

文章对竹柏( Podocarpus nagi)种子的脱水耐性和贮藏特性进行了研究,结果表明：竹柏种子成熟时初始含水量约为(35±0?7)％,种子对脱水敏感,其最低安全含水量约为(16?86±0?73)％,具有顽拗性种子的典型特征;湿藏和半干藏都可以作为短期保存竹柏种子的方法,且以4℃保存优于15℃保存,但不管种子含水量如何,零下低温保存对竹柏种子都是致命的;半干藏法保存实验中,未进行脱水处理的种子(对照)在4℃贮藏6个月,种子萌发率没有发生明显下降,但贮藏期延长到9个月时,临界含水量的种子萌发力保存最高;不管贮藏介质的含水量高低,也无论贮藏在4℃还是15℃,湿藏种子在9个月的贮藏期内萌发率均没有明显的降低,但当贮藏到12个月时,15℃湿藏种子的萌发率显著高于4℃贮藏的种子,但15℃湿藏的种子在贮藏到3个月时即发现种子在贮藏期间萌发,且随着贮藏介质含水量的升高和贮藏期的延长,萌发的种子增多;竹柏的离体胚经过2h硅胶快速脱水至含水量7％后再冷冻即可获得90％以上的融后存活率,且超低温保存1年的离体胚解冻后,与只保存1周的存活率没有明显差异,表明超低温长期保存竹柏种子是可行的。本研究可以为进一步探究顽拗性种子的短期贮藏和长期保存提供理论基础和基础资料。     

狼毒种子萌发特性与种群更新机制的研究

研究了采集于植株上的和收集于土壤种子库的狼毒(Stellera chamaejasme)种子在不同温度、光照和5种预处理(即破裂种皮、去除种皮、98％H2SO4浸种5min、0．2％KNO3浸种24h、10℃低温保存1周)条件下的萌发力。结果表明,狼毒种子萌发率较低,25℃恒温、黑暗条件下萌发率为13％,较适宜的萌发温度为30℃恒温或10～30℃变温,破裂种皮和去除种皮萌发率显著提高,25℃恒温、光暗交替条件下萌发率分别为49％和47％,浓硫酸浸种5min处理萌发率可达到32％,KON3浸种和10℃低温保存两个处理对促进狼毒种子萌发效果不明显,狼毒种子萌发对光照条件不敏感,种子硬实性是导致狼毒种子萌发率较低的主要原因,取自土壤种子库内的狼毒种子萌发率高于当年采集的种子,在自然条件下,并非每年都有狼毒种子萌发长成幼苗,种群更新时机是随机的或周期性的。     

温度、土壤水分和NaCl对黄顶菊种子萌发的影响

光照和黑暗条件下的黄顶菊种子萌发无显著差异;种子萌发的适宜温度为25—35℃;种子萌发率随着NaCl浓度的升高而下降;种子萌发的最佳土壤含水量为35％-45％。在最适温度下,种子萌发耐受NaCl的临界值为89．919mmol·L^-1极限值为218．92mmol·L^-1;不同温度和NaCl以及二者共同作用使黄顶菊种子萌发受到的抑制都极显著。     

顽拗性竹柏种子的贮藏特性

文章对竹柏(Podocarpus nagi)种子的脱水耐性和贮藏特性进行了研究,结果表明:竹柏种子成熟时初始含水量约为(35±0.7)%,种子对脱水敏感,其最低安全含水量约为(16.86±0.73)%,具有顽拗性种子的典型特征;湿藏和半干藏都可以作为短期保存竹柏种子的方法,且以4℃保存优于15℃保存,但不管种子含水量如何,零下低温保存对竹柏种子都是致命的;半干藏法保存实验中,未进行脱水处理的种子(对照)在4℃贮藏6个月,种子萌发率没有发生明显下降,但贮藏期延长到9个月时,临界含水量的种子萌发力保存最高;不管贮藏介质的含水量高低,也无论贮藏在4℃还是15℃,湿藏种子在9个月的贮藏期内萌发率均没有明显的降低,但当贮藏到12个月时,15℃湿藏种子的萌发率显著高于4℃贮藏的种子,但15℃湿藏的种子在贮藏到3个月时即发现种子在贮藏期间萌发,且随着贮藏介质含水量的升高和贮藏期的延长,萌发的种子增多;竹柏的离体胚经过2 h硅胶快速脱水至含水量7%后再冷冻即可获得90%以上的融后存活率,且超低温保存1年的离体胚解冻后,与只保存1周的存活率没有明显差异,表明超低温长期保存竹柏种子是可行的。本研究可以为进一步探究顽拗性种子的短期贮藏和长期保存提供理论基础和基础资料。     

白木香种子脱水耐性的发育变化及贮藏特性

研究白木香种子发育进程中种子性状、萌发能力和脱水耐性的变化,以及不同光温条件对种子萌发的影响和种子的贮藏特性。结果表明：白木香种子在花后78d获得最大干重,进入生理成熟期,此时萌发率接近最大值;胚在花后57～85d,脱水耐性逐渐增强,并在花后85d获得最大脱水耐性。种子萌发的适宜温度范围为25℃-35℃,光照对种子萌发有一定的抑制作用。新鲜自木香种子（含水量27．45％）在4℃低温条件下贮藏1个月后萌发率仅为30％左右,而含水量7．38％的干燥种子在4℃低温条件下贮藏120d,萌发率仍有53．33％,因此,4℃低温和适度脱水有利于种子短期贮藏。白木香种子能忍耐一定程度的脱水,但干燥至含水量7．50％以下时种子会发生损伤,因此推测白木香种子是一种中间性种子。     

温度、土壤水分和NaCl对黄顶菊种子萌以的影响

光照和黑暗条件下的黄顶菊种子萌发无显著差异;种子萌发的适宜温度为25～35℃:种子萌发率随着NaCl浓度的升高而下降;种子萌发的最佳土壤含水量为35%～45%.在最适温度下,种子萌发耐受NaCI的临界值为89.919 mmol·L-1,极限值为218.92 mm01.L-1;不同温度和NaCl以及二者共同作用使黄顶菊种子萌发受到的抑制都极显著.     

温度和硬实对金花菜种子萌发的影响

为科学指导金花菜的田间生产,以不同来源的5份金花菜(Medicago polymorpha L.)种子为试验材料,研究其在不同温度(5、10、15、20、25、30、35、40℃)下和破除种皮后的萌发情况。结果表明:海门、扬中、江都金花菜种子萌发率在20℃左右达到最大值,分别是43%、60%、59%。海安金花菜种子在25℃下萌发率最高,为24%;温岭金花菜种子则在15℃和25℃下萌发率达最高,均为22%。40℃时金花菜种子均无法萌发。金花菜的种皮硬实是限制其萌发的重要因素。不同来源金花菜种子的硬实情况差异较大,海安、海门、扬中、江都、温岭等金花菜种子硬实率分别为84.67%、50.83%、40.50%、37.67%、67.67%。破除种皮硬实可明显提高金花菜种子的萌发率。     

温度和土壤含水量对青冈栎种子萌发的影响

运用直播法,研究应用人工气候箱控制温度和土壤含水量对野生青冈栎种子萌发和幼苗生长的影响。结果表明:在12h光照条件下,青冈栎种子在变温为10℃/15℃时,萌发率很低,仅为(12±12.29)%;变温为30℃/35℃时,萌发率达最大,为(81±13.7)%。土壤含水量为30%～40%时,萌发率为(79±15.9)%;土壤含水量为90%～100%时,萌发率为(56.67±19.36)%。青冈栎种子萌发呈现出迅速萌发和推迟萌发的特点;温度对青冈栎幼苗的苗高、叶长和叶宽影响显著,对幼苗的地径、叶片数量影响不显著。恒温下,不同梯度土壤含水量处理对幼苗的苗高、地径、叶长、宽影响不显著。     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV     

Similar aerosol emission rates and viral loads in upper respiratory tracts for COVID-19 patients with Delta and Omicron variant infection

Highlights
1 Aerosol emission rates of Delta or Omicron patients were similar.
2 Viral loads in upper respiratory tract of Alpha, Delta and Omicron patients were similar.
3 Viral loads in upper respiratory tract of vaccinated or unvaccinated Delta patients had no difference.     

Recombinant human interferon-α1b inhibits SARS-CoV-2 better than interferon-α2b in vitro

Highlights
1) A comprehensive evaluation method for anti-SARS-CoV-2 drugs was established based on RT-qPCR, TCID₅₀ method, and immunofluorescence.
2) A significant antiviral effect of rHuIFN-α1b was shown with EC₅₀=0.12 IU/mL in Vero cells and EC₅₀=0.52 IU/mL in Calu-3 cells, which was better than rHuIFN-α2b (EC₅₀=0.25 IU/mL in Vero cells and EC₅₀=2.48 IU/mL in Calu-3 cells).
3) rHuIFN-α1b has a good potential in the application of anti-COVID-19 therapy.     

Continued antigenic variation of highly pathogenic avian influenza A (H7N9) virus in laying hens in China, 2020–2021

Highlights
1. 13 strains of H7N9 viruses from laying hens in 2020 and 2021 were identified.
2. H7N9 viruses in China comprised at least 11 genotypes.
3. H7N9 viruses are high pathogenic in chickens, not in ducks.
4. The most H7N9 viruses cross-reacted poorly with H7-Re3 antiserum.
5. The H7-Re3 vaccine was unable to prevent H7N9 infection.