密植条件下种植方式对夏玉米群体根冠特性及产量的影响

选用平展大穗型品种鲁单981(Ludan981,LD981)和紧凑中穗型品种鲁单818(Ludan818,LD818),在两种种植密度(60000和90000株/hm2)和两种种植方式(单株和双株)下,研究了密植及种植方式对夏玉米冠层和根系结构与功能以及子粒产量等的影响.研究发现,随种植密度增加,冠层垂直分布呈现干重比例权重上移的趋势,根系则呈现下移的趋势.密植条件下,LD981冠层对生长空间更为敏感,其根系对生长空间的竞争强于冠层,其群体产量限制因素是子粒库容;LD818根系对生长空间更为敏感,冠层对生长空间的竞争强于根系,其群体产量限制因素是单位面积穗数.60000株/hm2下,LD981的群体结构质量和功能较优,双株种植可缓解其冠层竞争,根、冠协调,表现增产;在90000株/hm2下,LD818的群体结构质量和功能较优,双株种植可缓解其根系竞争,部分改善冠层群体结构质量和功能,根、冠协调,表现增产.     

行距对晚播冬小麦群体的调节效应

为了明确行距对晚播冬小麦群体的调节效应,在2011—2013年度,以"济麦22"为试验材料,在晚播条件下设置3个行距处理(12、20、30 cm),比较了不同行距类型群体生育后期的冠层结构和冠层下部环境的差异、群体内植株个体性状及变异程度、产量和产量构成因素的变化。结果表明:行距缩小至12 cm,群体生育后期的叶面积指数显著提高,中上部冠层的光能截获显著增加、冠层下部的漏光损失显著减小;与20 cm和30 cm行距相比,12 cm行距群体内部的最高温度分别降低0.9和2.5℃,相对湿度增加0.3%和0.9%;行距缩小后,群体内单株性状的变异程度缩小,穗长和小穗数显著增加,单株穗粒重变异系数缩小,群体产量的稳定性提高,产量增加7.8%~24.5%。研究认为,窄行距(12 cm)播种有利于提高华北平原干旱缺水地区晚播冬小麦的群体产量。     

水平结构配置对冬小麦冠层垂直结构、微环境及产量的影响

作物的冠层结构是影响产量的重要因素, 群体微环境反映了作物冠层内小气候的变化, 与作物的冠层结构及产量形成密切相关。该研究在大田试验条件下, 设置等行距(R₁, 20 cm + 20 cm)、宽窄行(R₂, 12 cm + 12 cm + 12 cm + 24 cm)两种不同行距和低(D₁, 120.0 kg·hm^-2)、中(D₂, 157.5 kg·hm^-2)、高(D₃, 195.0 kg·hm^-2) 3个播量配置组合, 分析了不同处理组合下冬小麦(Triticum aestivum)生育后期冠层垂直结构、群体微环境及产量表现, 旨在优化小麦绿色栽培措施, 在不增加水肥投入情况下, 挖掘冬小麦的生产潜力和进一步增产的可能性和可行性。结果表明: 冬小麦上、中、下3个层次冠层开度(DIFN)、平均叶倾角(MLA)及叶面积指数(LAI)均表现为R₂大于R₁, 且R₂行距上层和中层DIFN、各层次MLA及LAI显著高于R₁, 在相同行距下, D₃播量LAI下降迅速, D₂播量的LAI及其中层和下层的MLA最高, 并与D₁、D₃差异显著; 冬小麦冠层温度和群体CO₂浓度均随着播量的增大而降低, 而相对湿度随播量增大而增大; 在相同播量下, R₂行距较R₁更具有降温保湿能力, 冠层平均温度较R₁下降了0.06-0.5 ℃, 相对湿度较R₁提高了1.85%-3.15%; 在相同播量下, R₂行距千粒质量、穗粒数都显著大于R₁, 因此R₂籽粒产量也显著高于R₁。综上所述, 冬小麦的水平结构配置可显著改变其冠层的垂直结构及群体微环境, 有利于冬小麦生长发育后期籽粒的灌浆, 在不减少穗数的情况下, 提高穗粒数及千粒质量, 从而达到增产目的。在该试验中以R₂D₂配置的冠层结构、群体微环境及产量最佳。     

不同群体结构夏玉米灌浆期光合特征和产量变化

大田试验以夏玉米为试料,采用裂裂区试验设计,密度设计包含75000、90000\,105000株/hm² 3个密度作为主区,每个密度处理包括: ①等行距60 cm×单株留苗,②等行距60 cm×双株三角留苗,③宽窄行距(宽行70 cm + 窄行距50 cm)×单株留苗和 ④宽窄行距×双株三角留苗共12种方式进行处理,测定光合及叶绿素荧光参数。研究不同群体结构对夏玉米灌浆期群体光合特性的影响。结果表明,在吐丝期,随着种植密度的增加,群体光合速率提高;蜡熟期以90000株/hm²最高,种植方式上表现为宽窄行大于等行距种植,双株留苗种植方式大于单株种植方式,差异均达到显著水平;随着种植密度的提高,群体内3个层次叶片最大光能转换效率(Fv/Fm)、光化学猝灭系数(qP)逐渐降低,种植方式基本表现为宽窄行大于等行距,留苗方式表现为双株大于单株。试验条件下,以90000株/hm²,宽窄行,双株三角留苗产量最高。     

黄土塬区不同品种玉米间作群体生长特征的动态变化

不同玉米品种间作,品种间的竞争对群体结构和产量可能有促进作用.为了明确不同密度下品种间作对不同生育期群体生长特征的影响,以及在不同生育期的变化规律,选用郑单958和沈单16两个不同株型的玉米品种在中、高两种密度条件下进行隔行间作田间试验.研究结果表明:不同密度间作群体叶面积指数(Leaf Area Index,LAI)显著增加,同密度不同品种间作LAI在生育后期显著增加,有利于形成合理的冠层结构以获得更多的光照;中等密度下品种间作单株叶面积较单作显著增加,而高密度间作显著降低了单株叶面积;中等密度下,品种间作地上部干物质积累量显著增加,郑单958尤为突出,但高密度间作时的增加幅度较小,这与高密度下株高、茎粗相对减小有关.品种株高、茎粗随间作密度的增加而有所增加,对间作竞争的响应与品种特性密切相关;在不同生育期,郑单958和沈单16号表现不同的生长规律,前者在整个营养生长过程中对间作竞争的响应明显、持续和稳定,而进入生殖期后,间作的生长优势逐渐消失;后者在营养生长期干物质积累量大,但持续时间较短,表现出较弱的竞争性.品种间作可有效改善群体冠层结构,增加群体物质生产力,更好的为增产鉴定基础.     

种植密度对川中丘区夏玉米冠层结构、干物质积累及产量的影响

通过设置4.50×104、5.25×104、6.00×104、6.75×104、7.50×104株·hm~(-2)(分别用T1、T2、T3、T4、T5表示)5个密度,研究种植密度对玉米冠层结构、干物质积累及产量的影响,为川中丘区夏玉米高产栽培提供理论依据和技术支撑。结果表明:随种植密度增加,玉米叶面积指数显著增加,茎粗、茎叶夹角和透光率显著降低;密度每增加1×104株·hm~(-2),茎粗分别降低1.4 mm(2015年)和1.3 mm(2016年),穗下、穗上第1叶夹角分别降低3.601°、1.440°,吐丝期和灌浆中期底层透光率分别降低3.73%和2.82%;玉米单株干物质积累随种植密度增加显著降低,T5较T1在成熟期分别降低37.13%(2015年)、25.95%(2016年);而群体干物质随种植密度呈增加趋势,2016年T5较T1在吐丝后7天、成熟期分别增加了26.72%、23.41%;玉米产量随种植密度呈先增后降的变化趋势,在密度为6.00×104株·hm~(-2)下产量最高;该密度下玉米群体和个体功能达到协同增益,玉米产量构成(有效穗数、穗粒数和千粒重)协调,是产量提高的主要原因。     

密度、种植方式和品种对夏玉米群体发育特征的影响

在豫北高产灌区的生产条件下,以郑单958和浚单20为试验材料,研究了不同密度和种植方式对夏玉米群体发育特征的影响。结果表明:密度和种植方式对两个品种的株高、茎粗、穗位、叶面积指数(LAI)、叶绿素含量、干物质积累量、穗部性状、籽粒产量和经济系数的影响达到极显著水平。郑单958在宽窄行种植方式和90000株/hm2的密度下产量最高,达到14236.97kg/hm2,浚单20在宽窄行种植方式和82500株/hm2的密度下产量最高,达到13333.51kg/hm2。     

水稻冠层光合有效辐射的时空分布特征

以2个不同株型水稻品种为材料,设置高、中、低3个施氮水平,利用SunScan冠层分析仪于灌浆期系统测定了不同施氮水平下不同株型水稻品种植株形态和冠层内光合有效辐射（PAR）的时空分布状况.结果表明：施氮量对水稻株高、穗弯曲度和茎叶夹角有明显影响;群体叶面积的垂直分布呈中部>上部>下部的分布特征,最大分层叶面积指数（LAI）出现在0.60相对高度处.冠层内平均PAR透光率从顶部向下递减,且在冠层上中部递减迅速,下部递减缓慢;平均PAR透光率随施氮量的增加而递减;平均PAR透光率日变化表现为早晚较低,中午较高;平均PAR透光率随向下累积LAI的增加呈指数递减,群体消光系数K的日变化表现为早晚较高,中午较低,灌浆期的K值介于0.35～0.50.水稻冠层内PAR的三维空间分布表现为冠层上中部水平面上PAR透光率高,光斑面积大;下部水平面上PAR透光率低,光斑少;同一冠层高度水平面上的PAR光强呈不均匀分布.株型紧凑的水稻品种,冠层透光率高,透光率日变化大,群体消光系数小.     

遮阴和种植密度对东北春玉米穗部发育和植株生产力的影响

探讨遮阴对玉米穗部特性的影响及其产量效应,可以为应对气候变化与密植栽培条件下的玉米品种选育和高产栽培提供参考依据.本研究选用2个品种(紧凑型‘中单909’、平展型‘内单4’)和2个种植密度(4.5、9.0万株·hm^-2),在吉林省公主岭市开展田间遮阴试验,设置遮阴(遮阴度65%,小喇叭口期-成熟期)和不遮阴(对照)2个处理,研究遮阴和种植密度对不同株型玉米的穗部发育和植株生产力的影响.结果表明: 遮阴显著影响春玉米雌穗发育,造成散粉和吐丝期推迟,导致散粉吐丝间隔期延长3～15 d;遮阴显著降低春玉米干物质积累,籽粒产量下降50%以上(50.8%～87.0%);密植条件下春玉米穗部特性和产量性能受遮阴的影响显著高于稀植栽培;不同玉米品种相比,紧凑型品种的穗部特性和产量受遮阴和种植密度的影响低于平展型品种,紧凑型品种对生态环境变化的适应性较强,耐阴性和耐密性表现出一致性.     

超高产小麦冠层光辐射特征的研究

在超高产栽培条件下,对多穗型小麦品种豫麦49的冠层光辐射特征进行了研究.结果表明,豫麦49叶面积指数 LAI 全生育期变化为单峰曲线,由越冬期开始逐渐增大,于开花期达最大值,之后下降.开花后D2 基本苗为150×104株/hm2 处理绿叶面积保持时间较长.其叶片分布 LD 处理间存在显著差异,但以D2处理的LD较为合理.各时期处理间平均叶倾角 MFIA 均为高密度的大于低密度的,返青以前不同处理间的差异较小,拔节以后差异增大,灌浆后期各处理MFIA均有减小趋势.消光系数 K 随天顶角增大而增大,D2处理冠层消光系数适中,且分配较优.冠层直射辐射透过系数 TR 随天顶角增大逐渐减小,开花期各处理之间差异显著,灌浆中期各处理之间差异减小.D2处理因其产量三因素协调而产量显著高于其它处理.综合以上结果可知,豫麦49在超高产条件下以D2处理的冠层结构最优,表现为LAI大小适中,叶片分布均匀,冠层消光系数分布合理,光能利用率较高.     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.     

The mechanism of hatching of eggs of Haemonchus contortus

Fluid collected from hatching eggs of Haemonchus contortus contained a lipase which hydrolysed 2-naphthyl laurate (about 0·7 μmol naphthol freed /h/10⁶ eggs). The fluid also hydrolysed l-leucinamide (about 2·3 μmol leucine freed/h/10⁶ eggs). The fluid when added to normal or heated eggs caused ‘hatching’. ‘Hatching’ also occurred in exsheathing fluid from infective juveniles and in a preparation of pancreatic lipase containing leucine aminopeptidase. A purified mammalian leucine aminopeptidase in combination with several different lipases did not attack egg shells.The ‘spontaneous’ hatching of eggs of H. contortus was strongly inhibited by 1,10-phenanthroline, 10^?3M, and this inhibition was reversed by Zn²⁺. However, the inhibition of ‘hatching’ of eggs in externally applied hatching fluid, or the hydrolysis of leucinamide in hatching fluid was generally less marked.