Effect of two plant growth retardants on steviol glycosides content and antioxidant capacity in Stevia (Stevia rebaudiana Bertoni)

Two greenhouse experiments were conducted to study the effect of two plant growth retardants, Chlorocholine chloride (CCC) and Paclobutrazol (PBZ), on growth, Steviol glycosides (SVglys) content and antioxidant capacity in Stevia (Stevia rebaudiana Bertoni). Five concentrations of CCC (0, 250, 500, 750 and 1,000 ppm) and PBZ (0, 6, 12, 18 and 24 ppm) with three replications were applied to Stevia plants as treatments based on completely randomized design. CCC was sprayed on Stevia shoots, but PBZ was applied as a drench. The obtained results showed that CCC reduced plant height but improved leaf and stem dry weight, especially with 750 ppm concentration. Total SVgly content and consequently SVglys yield were significantly reduced by CCC application, and 1,000 ppm of CCC concentration was more effective than other treatments. PBZ had no effect on Stevia height while it significantly enhanced stem and dry weight at 12 ppm. Moreover, PBZ remarkably increased total SVglys contents, SVglys yield, and Rebaudioside A/Stevioside ratio. Total antioxidant capacity significantly varied with CCC and PBZ and the highest activity was obtained with 1,000 and 12 ppm of CCC and PBZ, respectively. The results of these experiments indicated that, although CCC and PBZ are plant growth retardants and act as anti-gibberellins, only CCC reduced plant height and SVglys production in Stevia. On the contrary, PBZ at 12 ppm concentration, improved Stevia growth, SVglys production, and antioxidant capacity.     

Effect of ethrel,chlormequat chloride and paclobutrazol on growth and pyrethrins accumulation in <Emphasis Type="Italic">Chrysanthemum cinerariaefolium</Emphasis> Vis.

Pyrethrins and flower yield of pyrethrum (Chrysanthemum cinerariaefolium Viz.) plants were determined after application of ethrel, chlormequat chloride and paclobutrazol. Ethrel at 50, 100, 250 and 500 mg l^−l produced a significant positive effect on pyrethrins level, decreased plant height, while 50 and 100 mg l^−l significantly increased fresh and dry flower yield. Chlormequat chloride at 1000 and 2000 mg l^−l and paclobutrazol (80 and 160 mg l^−l) increased pyrethrins level, single flower weight and decreased plant height and flower yield. ¹⁴C-acetate incorporation studies further substantiated positive effect of growth retardants on pyrethrins biosynthesis. The effect of growth retardants on pyrethrins seems to be mediated through its effect on biosynthesis.     

The effects of mechanically-induced stress and plant growth regulators on the growth of lettuce,cauliflower and bean (Phaseolus vulgaris L.) plants

The plant growth regulators, gibberellic acid (GA₃), ethephon and chlormequat chloride (CCC) were sprayed on young lettuce, cauliflower and bean (Phaseolus vulgaris) plants, which had either been given or not been given a mechanically-induced stress (MIS) treatment. MIS was applied by brushing the plants with paper for 1.5 minutes each day. GA₃ increased extension growth of bean and leaf length of lettuce in unbrushed plants as much as in brushed ones. CCC and ethephon were less effective at reducing the height of brushed bean plants compared to unbrushed ones. The effects of CCC on the growth of cauliflower and lettuce plants was not influenced by brushing, whereas unbrushed plants responded more readily to ethephon than did brushed ones. The effects of CCC on growth were generally similar to those of MIS whereas the effects of ethephon were in many ways different to MIS.The results are discussed in relation to the use of PGR and MIS treatments for modifying plant growth.     

狭叶红景天幼苗对水分及遮阴的生长及生理生化响应

研究植物对水分和遮阴胁迫的响应及其生理机制对制定合理的栽培管理措施十分必要。以红景天属植物为研究对象,设置土壤含水量分别为田间持水量的80%(过湿水分)、70%(正常水分)、60%(轻度干旱)、40%(中度干旱)、20%(重度干旱)5个水分梯度;设置2个遮阴处理,以全光照(遮阴率为0)为对照、黑色遮阴网遮阴(遮阴率为85%),研究狭叶红景天生长及生理生化指标的变化特征。结果表明:在不同水分处理下,与对照相比,叶绿素含量、茎干重和茎重比(SMR)显著增加(P0.05),株高、总生物量、叶面积、叶干重、叶重比(LMR)、比叶面积(SLA)、叶面积比(LAR)和叶面积根干重比(LARMR)增加,根冠比和根重比(RMR)减少;随着干旱程度加剧,丙二醛(MDA)、脯氨酸(Pro)和可溶性糖(Ss)含量增加,超氧化物歧化酶(SOD)活性总体呈先增加后减小的趋势。在遮阴处理下,株高、SMR、SLA、LAR和LARMR显著增加(P0.05),叶绿素SPAD值和叶面积增加,总生物量、根干重、根冠比和LMR显著减少(P0.05),茎干重和叶干重减少,MDA含量显著增加,Pro含量略有下降,Ss含量减少。在水分胁迫下,狭叶红景天中度干旱时通过增加酶活性抵御伤害,重度干旱超过其阈值,SOD活性下降,植物体受到伤害,Ss可能是主要的渗透调节物质。在遮阴处理下,狭叶红景天通过增加SLA避免遮阴伤害。狭叶红景天在受到环境胁迫时会通过形态改变、调节MDA含量、抗氧化酶活性和渗透调节物质来保证自身正常的生长发育。     

Contribution of the wheat (Triticum aestivum L.) flag leaf to grain yield in response to plant growth regulators

In West-Europe, intensive cereal management uses plant growth regulators (PGRs) especially for wheat. A green-house experiment compared the effects of two PGRs on flag leaf characteristics and yield of winter wheat. Chlormequat chloride + choline chloride (CCC) and chlormequat chloride + choline chloride + imazaquin (CCC+I) were applied to winter wheat at growth stage 5 (Feekes Large scale). CCC and CCC+I significantly increased flag leaf surface area at anthesis. Both treatments also enhanced chlorophyll content of the main stem flag leaf. The grain filling period was extended with PGR application by 2 days. CCC and CCC+I significantly increased net CO₂ assimilation rates during the flag leaf life. No effects of PGR spraying were observed on the pattern of ¹⁴C labelled assimilate distribution. Increased grain yield was due to the increase in average grain weight. The results indicate that PGR treatments increased flag leaf contribution to grain filling. The addition of imazaquin (I) to chlormequat (CCC) improved the effects of CCC.     

外源乙烯利施用时期对花生源库形成的调控效应

为了解决源库关系不协调而限制花生产量提高的问题,在大田栽培条件下,以‘山花9号’花生为试验材料,设置花后10、20、30 d 3个喷施时期,以不喷施处理为对照,探讨不同时期喷施乙烯利对花生源库形成的调控效应。结果表明: 花后10和20 d喷施乙烯利可显著减少花生的开花数量、果针数、幼果数,提高秕果数和饱果数,而花后30 d喷施处理对开花数量、果针数和幼果数无抑制作用。喷施乙烯利可以增加花生单株叶面积,开花后10 d喷施处理的单株叶面积增幅最大,随着喷施时期的推迟增幅减小。花后10和20 d喷施乙烯利显著提高了花生叶片的光合速率,但花后30 d喷施处理只能在短期内提高光合速率,对生育后期的叶片光合速率无显著影响。从源库综合性状来看,花后20 d喷施乙烯利的源库关系最协调,有利于促进同化物向荚果的运输,提高有效果比例和荚果充实度,从而提高产量。因此,喷施乙烯利是解决花生“花多不实、果多不饱”源库失衡现象的有效措施,生产中使用乙烯利控花应选择在开花后20 d喷施。     

Density-dependent responses of Picea purpurea seedlings for plant growth and resource allocation under elevated temperature

This study was conducted to determine whether plants in the presence or absence of competition differ in their responses to warming, and whether density modifies the effect of warming. Picea purourea seedlings were grown under ambient and warming (ambient +2.2 °C) conditions in climate control chambers with two different planting densities. After 4 years, seedlings were harvested and measured for height, stem diameter, leaf area, structural biomass, carbon, nitrogen, chlorophyll and carbohydrate levels of needles, branches, stem and roots. At low density, warming increased height, stem diameter, total leaf area biomass production and carbohydrate concentration per seedling, while it decreased C/N ratio for all plant parts, but did not affect chlorophyll content. By contrast, at high density, although warming increased biomass and total leaf area, it did not affect plant height and stem diameter. At the same time, it had different effects on chlorophyll content, C/N ratio and carbohydrate levels among plant parts. On the other hand, high density limited plant growth and altered resource allocation pattern. Our study demonstrates that planting densities decreased the temperature-induced growth enhancement of P. purpurea seedlings and the effects of warming on resource allocation not only showed density-dependence, but also vary with tissue age classes and root diameter; the responses of plants to elevated temperature, acquired from plants growing as individuals, may not be applicable to plants grown under intraspecific competition as typically found in the field.     

Effect of triacontanol and chlormequat on growth,plant hormones and artemisinin yield in Artemisia annua L.

Artemisinin and herbage yield of Artemisia annua plants were determined after application of triacontanol (tria.) and chlormequat (2-chloroethyltrimethylammonium chloride). Tria. at 1.0 and 1.5 mgl^–1 produced a statistically significant positive effect on artemisinin level as well as on plant height, leaf and herbage yield. Chlormequat at 1000 and 1500 mgl^–1 also increased artemisinin level, decreased the plant height at higher concentrations and increased the leaf and herbage yield at lower concentrations. Tria. application enhanced GA-like activity, but ABA levels decreased, while chlormequat increased ABA but reduced GA-like substances. The effect of Tria. on artemisinin yield seems to be mediated through its effect on plant growth.CIMAP Publication.     

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.     

中药渣蚓粪对玉米生长及土壤肥力特性的影响

采用盆栽试验,研究了中药渣蚓粪对玉米生长及土壤肥力的影响.结果表明: 随着蚓粪施用量的增加,玉米的株高、茎粗、叶面积、叶绿素含量均显著增加;生长60 d收获时,多数蚓粪处理的土壤容重显著降低;蚓粪处理的土壤pH显著高于对照和相应的化肥处理.蚓粪处理的土壤全氮、有机质含量也明显高于化肥处理,且随蚓粪施用量的增加,效果越趋显著.中药渣蚓粪可作为一种高效有机肥,其合理施用有助于改善土壤物理结构,缓解土壤的酸化进程,提高土壤有机质和氮素含量,有效促进作物生长.     

降水变化和种间竞争对红松和蒙古栎幼苗生长的影响

针对全球变暖导致的降水格局的变化,选择长白山红松针阔叶混交林主要树种蒙古栎和红松幼苗为研究对象,在野外自然条件下人工模拟增、减水30%对单种和混种的针阔叶树种形态、生长和生物量分配的影响. 结果表明：对于蒙古栎幼苗,与单种处理相比,混种显著增加了其冠幅和主根长,与对照处理相比,减水处理显著提高了其茎质比、降低了其主根长; 对于红松幼苗,与单种处理相比,混种显著减少了其基径、树高、叶片数和根、茎、叶质量及总干质量,与对照处理相比,减水处理显著降低了其主根长、叶片数、叶质量和总干质量以及叶质比,同时显著提高了茎质比. 增水处理对二者的影响均不显著. 在树木生长初期,种间竞争和降水格局变化对蒙古栎和红松幼苗形态和生长均产生显著影响,对红松幼苗的影响更大.     

不同生境下空心莲子草响应模拟昆虫采食的生长和化学防御策略

外来植物往往可以入侵多种生境并受到多种昆虫的采食,而不同生境条件将可能会影响这些入侵植物对昆虫采食的防御策略。以入侵我国的克隆植物——空心莲子草为研究对象,分别选择生长在水生生境、水陆两栖生境和陆生生境中的无性个体(分株),通过50%去叶处理模拟昆虫采食,分析不同生境下空心莲子草对模拟昆虫采食处理的生长及化学防御响应的差异。模拟昆虫采食处理显著抑制了陆生生境、水陆两栖生境以及水生生境下空心莲子草的根、茎、叶和总生物量,但对3种生境下空心莲子草的生物量分配(根冠比、根生物量分配、茎生物量分配和叶生物量分配)均无显著影响。陆生生境下空心莲子草根、茎和总生物量显著高于水陆两栖生境和水生生境,根冠比显著低于水陆两栖生境和水生生境。模拟昆虫采食处理显著降低了空心莲子草的木质素含量,而对单宁和总酚含量影响不显著。生境对木质素含量无显著影响,但陆生生境下空心莲子草单宁含量显著高于水陆两栖生境和水生生境,且总酚含量显著高于水陆两栖生境,表明陆生生境中空心莲子草具有更强的防御能力。空心莲子草木质素含量与总生物量无显著相关性,但在模拟采食情况下,其总酚含量与总生物量呈显著负相关,而无论模拟昆虫采食处理存在与否,空心莲子草单宁含量与总生物量均呈显著正相关。因此,空心莲子草存在昆虫介导的生长和化学防御之间的权衡,在昆虫采食的情况下可通过减少生长来增加对化学防御物质的投入,但生境对空心莲子草这种生长-防御权衡的影响十分有限。     

Effect on carrot root yield and size distribution of the growth-retardants chlormequat chloride and aminozide

In two experiments, foliar sprays of either chlormequat chloride or aminozide depressed top growth, increased root yield and enhanced leaf and root colour in six carrot cultivars. In the first experiment, a direct correlation between concentration of the two retardants and root yield was apparent within the range 0–2000 mg/1 a.i. applied as run-off sprays to two cultivars. In the second experiment, increases in total root and canning-size yield and root/shoot ratio were obtained with four cultivars, but the magnitude of these effects was dependent on the time at which the retardants were applied and the time of harvest of the crop. The effects of aminozide on root yield were less persistent than those of chlormequat chloride, the yield differences between untreated and aminozide-treated plots decreasing with time after application.     

不同基因型辣椒光合及生长特性对弱光的响应

通过遮光使光照强度降低65%～70%,以研究弱光条件对不同基因型辣椒光合特性、同化物分配、产量形成和幼苗生长的影响.结果表明：弱光下辣椒净光合速率（P_n）、暗呼吸速率（R_d）、夜间呼吸速率（R_n）、蒸腾速率（T_r）、水分利用效率（WUE）、光补偿点（LCP）、CO₂补偿点（CCP）和羧化效率（CE）下降,表观量子效率（AQY）上升.弱光下辣椒成株期光合作用的限制因素是非气孔因素.弱光处理使辣椒幼苗高/粗比和比叶面积增加,根/冠比、全株干样质量及壮苗指数显著下降.弱光显著抑制了辣椒生物产量与经济产量的形成,使植株同化物向茎叶的分配比例增加,向果实的分配比例减少.辣椒（果实味辣）在弱光下具有较低的光补偿点,以及较高的相对壮苗指数、相对单株产量和相对坐果率,耐弱光性普遍强于甜椒（果实味甜）.     

三峡库区多年高水位运行对消落带狗牙根生长恢复的影响

为深入了解三峡库区多年高水位运行对消落带优势植物生长恢复的影响,分别于2008年和2017年定量调研了库区长寿段消落带狗牙根(Cynodon dactylon)种群的变化,探讨了库区高水位运行对消落带狗牙根萌发、生长和物质分配的影响。结果表明,多年的高水位运行导致不定芽形成和萌发显著被促进,形成更多的分株;高水位运行导致狗牙根分株的株高、茎宽和叶片数被显著抑制,而叶长和种群的总叶片数被显著促进,且随着消落带水位的降低叶长呈降低趋势,而叶宽和总叶片数呈增加趋势;高水位运行导致狗牙根种群匍匐茎和地下茎的茎长、茎节数和总茎长均被显著促进,且随着消落带水位降低匍匐茎茎长和茎节数呈显著的降低趋势,而地下茎茎长和茎节数呈增加趋势;高水位运行导致狗牙根地下茎储存的干质量呈增加趋势,而分株和匍匐茎的干质量呈降低趋势,而且在种群物质分配中地下茎所占的比例呈增大趋势,低水位狗牙根种群的分株和高水位种群的匍匐茎所占的比例也呈增加趋势。因此,狗牙根不仅具有很强的耐淹和生长恢复能力,也具有很强的拓殖能力,可以作为库区中低位消落带恢复和重建的主要原生物种。     

稻鸭共生系统中鸭品种对水稻生长特性的影响

鸭子品种间的差异对稻鸭共生系统中水稻的生长特性可能有重要影响.为了探究鸭子品种对水稻生长特性的影响,选取水鸭(SY)、洋鸭(YY)和绿头鸭(LTY)3个常见鸭品种作为处理,以水稻常规单作(CK)为对照,采用随机区组设计的方法进行田间小区试验,研究其对水稻根部、茎部、叶部性状及水稻产量的影响.结果 表明:YY和LTY处理...     

淹水胁迫下江南牡丹生长及光合特性研究

以3年生江南牡丹品种‘凤丹白’为材料,利用盆栽淹水法,设置正常管理、轻度胁迫和重度胁迫3个水平,研究不同淹水胁迫水平对牡丹生长和光合特性的影响。结果表明：经过30 d胁迫后,正常管理、轻度胁迫和重度胁迫下的江南牡丹苗高生长量分别为3.6、1.1和0.73 cm,地径生长量分别为0.21、0.11和0.06 cm,植株总生物量增加量分别为7.0、3.0和2.75 g,淹水胁迫和正常生长差异显著,淹水胁迫严重影响了江南牡丹的生长。同时,在正常管理时,牡丹总叶绿素含量升高,而在淹水胁迫下呈下降趋势。淹水胁迫不同时间根系活力均呈下降趋势且随着胁迫程度的增加下降越大。正常管理下光合速率逐渐增加而胁迫条件下光合速率逐渐降低。同时胁迫条件下,牡丹蒸腾速率、气孔导度均明显下降;轻度淹水胁迫下胞间CO2浓度先升高后降低;而重度胁迫下胞间CO2浓度呈现逐渐升高的变化趋势。淹水胁迫对牡丹根系活力、茎段生长和叶片光合特性影响较大。该研究结果为江南牡丹耐涝胁迫机理研究奠定了理论基础。     

水分胁迫下烯效唑对百日草幼苗光合特性及叶解剖结构的影响

以百日草‘芳菲1号’为试材,研究不同水分胁迫下烯效唑(S3307)对其幼苗生长、光合特性及叶解剖结构的影响,以明确S3307对百日草的抗旱作用及其机理。结果显示:(1)在水分胁迫下,百日草的生长均受到不同程度的抑制,叶绿素含量显著降低,光合作用受到抑制,叶解剖结构有所变化。(2)S3307处理后,均能够显著降低所对应的不同程度水分胁迫下百日草的株高,显著增加茎粗、叶面积、叶片厚度、栅栏组织厚度和根冠比,显著增加叶绿素含量,提高百日草的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)。研究表明,S3307能够提高百日草的抗旱性,而且在轻度和中度水分胁迫下Pn的下降主要是由气孔因素引起,而在重度水分胁迫下光合速率的下降是由非气孔因素引起的。     

积雪变化对高寒草甸钝苞雪莲(Saussurea nigrescens)繁殖分配及功能属性的影响

季节性雪被对植物的生长繁殖具有深刻影响。为阐明不同积雪梯度下钝苞雪莲各器官生物量、养分含量、繁殖分配及功能属性的变化规律,在青藏高原东缘红原县,通过人工堆积的方法开展积雪梯度（CK、S0、S1、S2、S3）控制实验,测量了不同积雪梯度下钝苞雪莲茎、叶、花苞的养分含量及繁殖分配等特征。结果表明：1）积雪变化没有显著改变钝苞雪莲的繁殖分配,但去除积雪（S0）显著降低了营养器官生物量。2）不同积雪处理下,个体大小与繁殖器官生物量均呈正线性关系（P<0.01）。3）茎部磷（P）含量随积雪量的增加显著升高（P<0.05）;叶部P含量随积雪量的增加先上升后下降,即：S2 > S1 > CK > S3 > S0,且存在显著差异（P<0.05）;各处理下植物的不同器官在养分上主要受氮（N）元素的限制。4）去除积雪（S0）降低了茎干重、株高、茎高、茎分配和单株花苞量,过度积雪（S3）则降低了株高、茎高和花苞长度,中度积雪（S1、S2）则分别降低了花苞长度与单株叶片数。由此可见,不同积雪量并未显著改变钝苞雪莲的繁殖分配,但却改变了其不同器官的功能属性与养分含量,使磷元素成为植物响应积雪变化较为敏感的指标。     

干旱对东北春玉米生长发育和产量的影响

选取玉米品种丹玉39为供试材料,利用大型农田水分控制试验场,采用大田池栽方式,在玉米三叶-拔节期、拔节-吐丝期、吐丝-乳熟期分别开展中度干旱胁迫及复水控制对比试验,分析3个关键生育时期干旱胁迫对春玉米生长发育和产量的影响.结果表明：与水分适宜对照（CK）相比,三叶-拔节期遭受干旱胁迫后,全生育期推迟13 d,至拔节普遍期,株高偏低29.8%,叶面积偏小41.2%,复水后,株高和产量得到较大程度恢复,果穗性状和最终产量差异不大;拔节-吐丝期遭受干旱胁迫后,全生育期缩短7 d,至吐丝普遍期,株高偏低18.6%,叶面积偏小14.1%,果穗长、穗粒数、果穗干质量、穗粒质量分别下降6.9%、19.1%、28.1%和29.4%,空秆率增加13.3%;吐丝-乳熟期遭受干旱胁迫后,全生育期缩短15 d,生长至乳熟普遍期,株高偏低2.3%,叶面积偏小37.3%,果穗长、穗粒数、果穗干质量、穗粒质量分别下降9.2%、24.1%、30.8%和27.9%,空秆率增加24.5%.拔节-吐丝期、吐丝-乳熟期干旱胁迫处理并复水后,玉米株高恢复不明显,产量降幅显著.