多糖和激素对珠芽魔芋多叶形成的调控作用

【目的】探究多糖和激素对珠芽魔芋多叶形成的作用,为调控珠芽魔芋多叶萌发生长提供理论依据。【方法】2020年,分别采集自然生长珠芽魔芋1叶期至4叶期幼苗,以当年仅着生1片复叶的花魔芋为对照,测定各时期的叶柄长、球茎鲜质量和根长,以及各器官中还原性多糖、淀粉以及玉米素（ZT）、赤霉素(GA₃)、生长素（IAA）和脱落酸(ABA)含量变化;2021年,分别以20 μg/L ZT溶液和40 μg/L IAA溶液喷施珠芽魔芋幼苗,以喷施清水的珠芽魔芋幼苗为对照,分别采集幼苗1叶期至4叶期最新萌发嫩叶,测定各时期新叶中ZT、GA₃、IAA和ABA含量。【结果】（1）2020年,随着生长期延长,珠芽魔芋幼苗各生长时期的叶柄长、球茎鲜质量和根长均呈增加趋势,但是均低于花魔芋。各时期珠芽魔芋幼苗各器官中还原性多糖、淀粉含量均随着生长期的延长而增加;新叶中的还原性多糖和淀粉含量比老叶低。随着生长期的延长,珠芽魔芋幼苗叶片和根的ZT含量均明显增加,各时期新叶ZT含量比老叶低;而叶柄和球茎的ZT含量明显降低。随着生长期的延长,珠芽魔芋幼苗各器官中GA₃、IAA和ABA含量逐渐上升,新叶GA₃、IAA和ABA含量总体比老叶高。随着生长期的延长,各时期花魔芋不同器官糖和激素含量变化幅度较小,且均低于珠芽魔芋。（2）2021年,与对照相比,喷施ZT后,珠芽魔芋幼苗嫩叶ZT含量明显增加,且明显促进了幼苗侧叶形成速度;喷施IAA明显增加了幼苗IAA、GA₃和ABA含量,显著抑制了珠芽魔芋幼苗侧叶形成。【结论】珠芽魔芋中较高含量糖分和ZT及较低含量GA₃、IAA和ABA有利于珠芽魔芋侧叶萌发和生长。     

Lightwood induction in Pinus sylvestris by means of mechanical wounding

In a field experiment the influence of different girdling patterns like wide girdling, longitudinal debarking, debarking with one or several bridges, narrow girdling and bark crushing on resin soaked wood formation (lightwood) in Pinus sylvestris L. trees was investigated. Four years after treatment the concentrations of total extractives and resin acids were measured. It is shown that treatment methods differently affected concentrations of total extractives and resin acids. Longitudinal debarking with a wide bridge and debarking with several narrow bridges were the most successful methods for lightwood induction.     

Newly emerged nulliparous Culicoides imicola Kieffer (Diptera: Ceratopogonidae) with pigmented abdomen

The method of segregating nulliparous and parous females of Culicoides spp. based on the presence of burgundy-red pigment inside the abdominal wall of parous Culicoides midges, is used worldwide. Out of 320 females of Culicoides imicola trapped by emergence traps, set over an artificial breeding site for 10 and 24 days, 73 (22.8%) showed a red-pigmentation despite the fact that they were nulliparous. This finding indicated that 23% of the “parous” females that are examined for the presence of arboviruses and other pathogens or for age-grading purposes, are actually old nulliparous females, which had no chance of acquiring pathogens. This bias in parous rate distorts upward the calculation of vectorial capacity.     

三熟制油菜秸秆还田条件下施氮量对早稻产量形成和氮肥利用率的影响

为明确油-稻-稻三熟制油菜秸秆还田条件下早稻的适宜施氮量,2017-2018年以超级常规早稻中嘉早17为材料,设置0、75、120、165、210kg/hm ²等5个施氮量,探究油菜秸秆还田条件下施氮量对早稻产量形成及氮素吸收利用的影响。结果表明：在油菜秸秆还田条件下,适宜施氮量有利于早稻分蘖成穗,灌浆期维持较高的叶面积指数、光合势和干物质积累量,同步增加单位面积有效穗数和保持较多的每穗粒数,从而扩大总库容量。在施氮量为165kg/hm ²时早稻即可达到较高产量,同时维持较高的氮肥吸收利用率。采用线性加平台模型拟合得出最佳施氮量,2017和2018两年分别为155.91、160.37kg/hm ²,产量潜力分别达8 241.17和8 387.32kg/hm ²。     

打鼓坪林场常绿阔叶林群落类型分析

对打鼓坪林场常绿阔叶林的物种及植物群落进行调查,结果表明:该地区共有木本植物85科、240属、559种,植物区系属于热带、亚热带性质,并有较强的过渡性质;对群落植物生活型的统计分析说明该地群落植物生活型是相当丰富的;对植物群落类型统计得出该地拥有9个群系,并分别对每个群丛进行了群落类型、特征和分布的简要描述.     

MgH2-X(X=Si,Ge,Sn,Pb)体系解氢能力的第一原理计算

采用基于密度泛函理论的第一原理赝势平面波方法,研究了MgH2-X(X=Si,Ge,Sn,Pb)合金化体系的能量、几何与电子结构.负形成热的计算发现:合金化元素X在镁氢化合物(MgH2)中少量固溶时,体系相结构稳定性变差,预示着解氢能力得到改善.电子态密度(DOS)与电子密度的进一步分析发现:镁氢化合物X合金化后,X与其周围的H原子相互作用不明显,而Mg-H之间的成键作用减弱.体系Ge合金化解氢能力增强的理论计算与实验结果一致,预测Si,Sn,Pb少量固溶于MgH2能提高体系的解氢能力.     

Regeneration and transformation of cassava

A prerequisite for the development of a successful transformation system is the availability of efficient regeneration systems. Up to 1995 the only available regeneration system in cassava was an organized type of somatic embryogenesis. Transformation of these organized somatic embryogenic cultures with particle bombardment or Agrobacterium tumefaciens resulted in chimeric transformed embryos. However, the transformed sector was lost after repeated cycles of secondary somatic embryogenesis. After 1995 a less organized system of somatic embryogenesis was developed, so called friable embryogenic callus (FEC) and a system of adventitious shoot regeneration. The FEC regeneration system was combined successfully with particle bombardment. Selection of transgenic plants was based on either luciferase activity, or resistance to the aminoglycoside paromomycin or the herbicide phosphinothricin. Furthermore, protoplasts of FEC are able to regenerate into plants and can be transformed by electroporation. The adventitious shoot regeneration system was combined successfully with Agrobacterium tumefaciens. For this mature somatic embryos were cocultivated with Agrobacterium and cultured for adventitious shoot development. After selection based on the aminoglycoside geneticin or on hygromycin transgenic plants were formed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Indentification of strong and weak yield determining components of winter oilseed rape compared with winter wheat

Yield formation of winter oilseed rape was compared with that of winter wheat in terms of absorption of PAR, radiation use efficiency and harvest index by means of crop growth simulation. Cumulative incoming PAR from April 15 until maturity, cumulative absorption of PAR, radiation use efficiency and harvest index were lower for winter oilseed rape compared with winter wheat. To improve potential seed yield of winter oilseed rape, a crop type with increased cumulative absorption of PAR, radiation use efficiency and harvest index is desirable.     

茄子离体培养研究进展和展望

综述了茄子不同组织、器官产生愈伤组织，胚胎发生，根芽分化以及植株再生的影响因素和诱导条件。对茄子组织培养中器官发生规律、种质资源利用及技术实用化提出看法。     

In vitro chromosome doubling of Miscanthus sinensis

The aim was to develop an efficient chromosome doubling method for Miscanthus sinensis to enable the production of triploids and so avoid seed dispersal to the environment. Antimitotic treatments with colchicine or oryzalin were tested in M. sinensis cl. MS‐88‐110 on: (1) in vitro shoots and plants established in soil; (2) during propagation of embryogenic callus; and (c) during the initial stages of callus induction. All systems produced chromosome‐doubled plants. A higher percentage of tetraploids was found after antimitotic treatment at the explant or callus level compared with treatment of in vitro shoots or plants established in soil. In general, oryzalin was more toxic to plant material than colchicine. A higher frequency of chimeras was found among plants with altered ploidy level when the target was formed shoot buds compared with adventitious shoot formation from callus. Antimitotic treatment of embryogenic callus from shoot apices also resulted in a high degree of albinism.