断根对玉米幼苗根系生物学特性及水分代谢的影响

本研究以玉米（Zea mays L.）为试验材料,通过水培法研究了断根对玉米幼苗根系特性及水分导度的影响。结果表明：断根使玉米幼苗的整株根系水分导度提高,玉米叶片的光合速率、蒸腾速率及气孔导度下降,其中对蒸腾速率的影响最大;断根降低了玉米幼苗根系的根系总长、根表面积及根尖数,增加了根轴的平均根长,而断根后的根系平均直径与对照相比差异并不显著。     

UV-B辐射增强对甘薯光合特性和紫外吸收物质的影响

为探索UV-B辐射增强对甘薯光合特性和紫外吸收物质含量的影响,以徽薯为试验材料,以自然光为对照,设2个UV-B辐射增强处理[在自然光基础上增加UV-B辐射3.6和7.2kJ/(m ²·d)分别编号为T1、T2处理],测定不同辐射强度下光合色素含量、光合作用参数和紫外吸收物质含量。结果表明：叶绿素a（Chla）、叶绿素b（Chlb）、类胡萝卜素（Car）和叶绿素a/b的值均随UV-B辐射强度的增加而降低,且Chla、Chlb和Car分别在处理第100、80和40天时对辐射变化最敏感;净光合速率（P_n）显著下降,气孔导度（G_s）降低,胞间CO₂浓度（C_i）和蒸腾速率（T_r）无明显变化规律,气孔限制值（L_s）的变化趋势与C_i相反;紫外吸收物质显著升高,呈CK相似文献   

玉米自交系叶片水分利用效率差异性及其生理变化

为选育抗旱性强、耗水少、水分利用效率高的品种.以22个玉米自交系为材料,采取正常灌溉和适度水分胁迫处理,对自交系叶片水分利用效率(WUE)、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)、相对叶绿素值( SPAD)和荧光动力学参数进行研究.结果表明,不同自交系WUE差异显著,而且对水分的敏...     

甘蓝型油菜叶片和角果气体交换参数差异的比较

为探究油菜叶片与角果间光合特性的差异,以双低高油甘蓝型油菜杂交种秦优7号为材料,在不同光照、CO2浓度、温度和一日之内不同时间点等条件下比较了叶片和角果间气体交换参数的差别,结果显示:叶片和角果的气体交换参数随光强、CO2浓度、温度、一日之内时间的变化趋势基本相同。在同等光照条件下,叶片的净光合速率、气孔导度、水分利用效率和气孔限制值均高于角果,而胞间CO2浓度蒸腾速率低于角果;叶片的光饱和点、光补偿点、光呼吸速率明显比角果低,而光量子效率显著高于角果。在同等CO2浓度条件下叶片的净光合速率、水分利用效率、气孔限制值均明显高于角果,而胞间CO2浓度低于角果;叶片的CO2饱和点、CO2补偿点均比角果低,而羧化效率则显著高于角果。叶片进行光合反应的最适温度低于角果,在各自最适和相同温度范围内叶片的净光合速率、气孔导度、蒸腾速率、气孔限制值均明显高于角果,而叶片的胞间CO2浓度、水分利用效率则比角果明显降低。在整个日变化范围内叶片的净光合速率、气孔导度、气孔限制值、水分利用效率明显比角果高,而叶片的胞间CO2浓度、蒸腾速率则明显比角果低。     

液膜对棉花叶片蒸腾特性及水分利用效率的影响

研究了液膜不同浓度对棉花叶片净光合速率、蒸腾速率、气孔导度、叶绿素荧光诱导动力学参数及水分利用效率的影响。结果表明，液膜不同浓度均能降低棉花叶片的蒸腾速率和气孔导度；较高浓度液膜增大叶片qN值，降低叶片净光合速率；适宜浓度液膜(40～50倍)显著提高叶片水分利用效率，对净光合速率无明显影响。     

叶面肥“天达-2116植物细胞膜稳态剂”对烟草叶片气体交换特征的影响

摘要：为了揭示叶面肥“天达-2116”对烟草光合速率的影响,本试验对比分析了喷施和不喷施叶面肥“天达-2116”两种处理下,旺长期叶片的光合速率、蒸腾速率、气孔导度以及水分利用率对光强响应特征。结果表明：喷施叶面肥时烟草的光合速率、蒸腾速率、气孔导度都随光强的增强而逐渐增大。不喷施条件下,蒸腾速率和气孔导度随光强的增强而逐渐增大,而在高光强（>1200μmol s-1m-2）下,会产生光饱和现象。喷施叶面肥“天达-2116”条件下的光合速率、蒸腾速率、气孔导度均高于不喷施的,但并未改变水分利用效率。因此,适量喷施叶面肥“天达-2116”可以显著改善烟草叶片的的光合生理性状和气体交换能力。     

玉米叶片气孔特征及气体交换过程对气候变暖的响应

气孔是植物叶片表面控制大气与植物间气体交换的孔状结构,对于生态系统碳、水循环过程的调节起着非常重要的作用。本文利用典型农田生态系统实验增温平台,研究了未来气候变暖对玉米叶片的气孔特征(包括气孔频度、气孔开口大小和形状以及气孔分布格局)和气体交换过程的影响。结果表明:(1)尽管增温并没有改变气孔密度(P0.05),但却由于表皮细胞数目的减少导致气孔指数显著增加12%(P0.05);(2)增温使气孔开口的长度显著减小18%(P0.01),宽度增加26%(P0.01),面积和周长分别增加31%(P0.01)和13%(P0.05);(3)实验增温还使单个气孔之间最近邻域的平均距离显著增加,表明气孔在玉米叶片上的分布变得更加均匀;(4)增温导致玉米叶片的净光合反应速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)分别增加52%(P0.05)、163%(P0.001)和81%(P0.05);与此相反,玉米叶片的暗呼吸速率(Rd)却显著降低24%(P0.01)。增温没有对细胞间CO2浓度(Ci)和水分利用效率(WUE)产生显著的影响(P0.05)。本研究结果表明,未来全球气候变暖可能通过改变玉米叶片的气孔频度、气孔开口大小和形状及其在叶片上的空间分布格局来改变其气体交换过程。     

不同耐性烟草品种苗期叶片光合特性对低温胁迫的响应

对不同耐性烟草苗期叶片的光合特性在低温胁迫及其随后常温恢复生长条件下的变化进行了详细研究。结果表明,4℃~6℃的低温胁迫几乎完全抑制较耐冷烟草品种K326和敏感品种云烟97幼苗的生长,但在恢复至常温条件时K326的生长速度显著高于云烟97。低温胁迫降低烟草幼苗叶片的光合作用,而且胁迫时间越长,抑制效应越明显,处理6d后叶片气体交换参数净光合速率(Pn)、气孔导度(Gs) 、胞间CO2浓度(Ci) 、蒸腾速率(Tr)、水分利用效率(WUE)、气孔限制值(Ls)以及叶绿素荧光参数最大光化学效率(Fv/Fm)、PS II量子产量或光能捕获的效率(ΦPSII)、光化学猝灭系数(qP)、表观电子传导率(ETR)和非光化学猝灭系数(NPQ)均与处理前的差异达到了显著水平。恢复至常温生长条件时,幼苗叶片光合作用迅速得以增强,K326提高的幅度比云烟97大;虽然恢复至第9d时这两个品种的光合作用还没有回复到处理前的水平,但较耐冷品种K326的光合作用参数与处理前的差异较小,而低温敏感品种云烟97与处理前仍存在显著性差异。     

大气CO_2倍增条件下冬小麦气体交换对高温干旱及复水过程的响应

探究大气CO_2浓度倍增条件下冬小麦气体交换参数对高温干旱及复水过程的生理响应机制,有助于提高生态过程模型的模拟精度,更加准确地预测全球气候变化对农田生态系统初级生产力及其生态服务功能的影响。利用4个可精准控制CO_2浓度和温度的大型人工气候室,研究了CO_2浓度倍增条件下高温干旱及复水过程对冬小麦气孔特征和气体交换参数的影响。结果表明, CO_2浓度倍增(E)导致冬小麦远轴面气孔密度增加、气孔宽度减小、气孔空间分布规则程度降低,但提高叶片的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)。高温干旱(HD)使叶片气孔长度、密度、周长和面积减小,导致叶片气体交换参数均显著下降。然而,高CO_2浓度及高温干旱(EHD)导致气体交换参数下降幅度相对较小,表明高CO_2浓度对高温干旱具有一定的缓解作用。此外,干旱复水后,不同处理条件下冬小麦叶片气体交换参数均有所升高,但高温干旱下叶片的气体交换参数仍未能恢复到对照水平,暗示光合器官可能在高温干旱时遭到损伤和破坏。     

玉米、旱稻、豇豆、棉花叶片气体交换对水分胁迫的反应

四种作物叶片气体交换特性对水分胁迫的反应不同。高叶水势下,气孔阻力低,净光合速率是玉米>旱稻>豇豆>棉花,而蒸腾速率是棉花>豇豆>旱稻>玉米。气孔阻力对轻度水分亏缺无反应。随着水分胁迫加剧,叶水势达到某一阈值,气孔阻力突然增加。气孔开始关闭水势阈值分别为:-0.8(玉米)、-0.4(豇豆)、-1.2MPa(旱稻、棉花)。净光合速率     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.