激素及光照对甘薯茎尖分生组织培养的影响

根据不同基因型甘薯茎尖分生组织在不同激素水平的生长反应,将４个河南主栽甘薯品种分为３类;激素不敏感硬成苗型、激素敏感易成苗型和激素不敏感难成苗型。光照时数不是甘薯茎尖培养成苗的根制因素,以不低于１４ｈ／ｄ为好。     

毛竹退笋及丰产技术的研究

对毛竹退笋原因和影响退笋的因子进行调查研究,认为毛竹营养不良和虫害等是退笋的主要原因;竹鞭年龄及入士深度、母竹营养状况、竹笋形状及出土期等因素与退笋都有一定关系。据此,提出了培育优质竹林,留养小年笋,及时挖退笋的对策技术措施。     

Seasonal shoot and needle growth of loblolly pine responds to thinning, fertilization, and crown position

The impacts of thinning, fertilization and crown position on seasonal growth of current-year shoots and foliage were studied in a 13-year-old loblolly pine (Pinus taeda L.) plantation in the sixth post-treatment year (1994). Length of new flushes, and their needle length, leaf area, and oven-dry weight were measured in the upper and lower crown from March through November. Total shoot length was the cumulative length of all flushes on a given shoot and total leaf area per shoot was the sum of leaf areas of the flushes.

By the end of June, first-flush foliage reached 70% of the November needle length (14.3 cm) and 65% of the final leaf area (15.0 cm²). Cumulative shoot length of first- and second-flush shoots achieved 95% of the annual length (30.3 cm), whereas total leaf area per shoot was 55% of the final value (75.3 dm²). Fertilization consistently stimulated fascicle needle length, dry weight, and leaf area in the upper crown. Mean leaf area of upper-crown shoots was increased by 64% six years after fertilization. A significant thinning effect was found to decrease mean leaf area per shoot in the crown. For most of the growing season, the thinned-fertilized trees produced substantially more leaf area per shoot throughout the crown than the thinned-nonfertilized trees. These thinned-fertilized trees also had greater needle length and dry weight, longer first flush shoots, and more leaf area per flush than trees in the thinned-nonfertilized plots. Needle length and leaf area of first flush shoots between April and July were linearly related to previous-month canopy air temperature (T_a). Total shoot length strongly depended on vertical light gradient (PPFD) within the canopy, whereas shoot leaf area was a function of both PPFD and T_a. Thus, trees produced larger and heavier fascicles, more and longer flush shoots, and more leaf area per shoot in the upper crown than the lower crown. We conclude that thinning, fertilization, and crown position regulate annual leaf area production of current-year shoots largely by affecting the expansion of first flush shoots and their foliage during the first half of the growing season.     

白肋烟打顶技术探讨

通过对白肋烟的烟叶经济性状、烟株株型、烟叶成熟度及烟叶化学成分的比较分析认为,开花始期打顶的烟株,上下部叶片长势成熟均匀,烟叶成熟适宜,内在化学成分协调,因此,开花始期是最适宜的打顶期;留叶２０片左右烟叶化学成分协调,产量、产值高,是适宜的留叶数;打顶位置以倒数第４片叶和第５片叶之间为宜,留叶部位以此下数至适宜留叶数．     

关节间隙对机器人末端执行器位姿误差的影响

影响机器人末端执行器位姿的因素很多,其中关节间隙的影响历来为人们所关注。本文讨论了关节间隙对机器人末端执行器位姿误差的影响,推导出了由关节间隙引起的机器人末端执行器位姿误差的精确计算公式,且给出了算例,本文的工作为提高机器人的工作精度及有效地控制机器人,提供了理论依据。     

植物生长调节剂对不同马铃薯品种茎尖分生组织离体培养的影响

通过观测４个马铃薯品种剥离茎尖在１３种培养基上的生长发育,比较不同浓度的ＧＡ３、ＮＡＡ、６－ＢＡ、２,４－Ｄ及其组合对茎尖成活和成苗的诱导作用,表明以０．０５ｍｇ／Ｌ分别添加上述４种生长调节剂最适于马铃薯３３ｄ前的茎尖成活;ＧＡ３对茎尖成活和成苗存在促进作用。     

喷焊余温淬火改善深松铲尖铁基涂层耐磨性

针对深松铲尖耐磨性能差、失效频繁等问题,采用火焰喷焊技术在45钢基体上制备了铁基合金涂层,并利用喷焊后试件余温对其进行了淬火处理。利用扫描电镜、能谱仪、X射线仪分析了涂层显微组织、元素构成及物相组成,利用显微硬度计、磨损试验机测试了涂层显微硬度及磨损性能。结果表明,涂层与基体呈良好冶金结合,淬火涂层主要由碳化物Cr_(23)C_6、Cr_7C_3,硼化物Fe_2B,复合相(Cr,Fe)_7C_3以及固溶体γ-Fe(Cr,Ni,C,Si)等组成。与未淬火涂层相比,组织得到细化,涂层显微硬度平均为800 HV左右,较未淬火涂层提高了约100 HV。淬火涂层试件(45钢基体)和未淬火涂层试件(45钢基体)平均磨损质量分别为0.30和0.35 g;田间试验的涂层淬火深松铲尖(65Mn基体)磨损质量为32 g,无涂层65Mn铲尖为70 g,涂层深松铲尖具有较好的耐磨性,该研究可为延长深松铲尖使用寿命提供参考。     

掌叶半夏微茎尖培养脱毒和快繁体系的建立

研究了茎尖大小、激素浓度、培养基成分对药用植物掌叶半夏脱毒效果的影响以及影响无病毒苗快速繁殖的因素等,结果表明：茎尖大小是影响茎尖成活和脱毒效果的主要因素,0.2~0.5mm的茎尖培养在MS+6-BA 1.0mg/L+NAA 0.1mg/L+蔗糖30g/L+琼脂7g/L培养基上,成活率为53.3%,病毒脱除率为76.7%,培养基中附加247mg/L NH₄ ⁺可有效提高茎尖成活率至86.7%,同种培养基上继续培养,可一次性成功诱导形成试管苗,移栽成活率高达100%。MS+6-BA 2.0mg/L+NAA 0.5mg/L+GA₃ 0.5mg/L组合最有利于试管茎的形成和发育,从而建立了以掌叶半夏微茎尖为外植体的脱毒和快速繁殖体系。     

长白山单花橐吾茎尖离体培养研究

以单花橐吾(Ligularia jamesii)茎尖作为外植体进行幼芽诱导,探索单花橐吾的离体快繁途径。结果表明:在MS+6-BA(3.0 mg·L^-1)+NAA(0.3 mg·L^-1)+蔗糖(35 g·L^-1)培养基上的幼芽诱导效果最好,诱导率高达90.1%;增殖培养时在MS+6-BA(2.5 mg·L^-1)+IBA(0.1 mg·L^-1)培养基上的平均增殖系数4.9,幼芽生长健壮,可继代培养6次以上;生根培养采用1/2MS+NAA(0.5 mg·L^-1),生根率达95%,生根白色粗壮,且数量较多。