胡杨不同发育阶段叶片形态解剖学特征及其与胸径的关系

采用MSR-9600TFU2扫描仪和常规石蜡切片,分析胡杨不同发育阶段叶片形态解剖学特征及其与胸径的关系。结果表明:1叶片宽、叶面积、气孔密度、厚度均随胸径增加沿树冠基部向顶部方向逐渐增大,叶片长和叶形指数则随胸径增加沿树冠基部向顶部方向逐渐减小。2叶片上下表皮细胞数和表皮细胞长、栅栏组织厚度、栅栏组织细胞长和宽均随胸径增加沿树冠基部向顶部方向逐渐增大;海绵组织厚度随胸径的增加而逐渐减小,树冠基部向顶部方向则逐渐增大。3相关分析显示,叶片宽、叶面积和叶片厚度分别与胸径呈极显著/显著正相关,叶形指数与胸径呈极显著负相关;叶片栅栏组织厚度、表皮细胞数、表皮组织厚度、表皮细胞长分别与胸径呈极显著/显著正相关,海绵组织厚度与胸径呈极显著负相关;叶片形态指标与解剖结构指标间也存在正/负相关关系,表明胡杨叶形态结构变化与个体发育阶段密切相关。     

桃叶片组织解剖结构特征与其抗旱性关系的研究

对6个栽培桃品种的叶片组织结构进行解剖观察、比较、描述,并测定了叶片结构参数。结果表明,各品种间叶片厚度、表皮毛密度、上表皮细胞大小、气孔密度、栅栏组织厚度、海绵组织厚度、叶片组织结构紧密度、疏松度、栅栏组织/海绵组织厚度比等指标差异较大。表皮厚度、角质层厚度、气孔长度各品种间无明显差异。其中气孔密度大,栅栏组织较厚,叶片组织紧密度大、疏松度小,栅栏组织/海绵组织厚度比较高,上表皮细胞较小者抗旱性较强。     

几种除草剂和助剂对苜蓿Medicago sative出苗和生长的影响

在温室条件下研究了几种苗前除草剂单用或混用对苜蓿出苗和生长的影响,以及不同叶龄苜蓿对苗后除草剂的反应及添加助剂对药效的影响。结果表明:咪唑乙烟酸在60~120 g/hm2剂量下,于苗前施用,对苜蓿出苗和幼苗生长都有明显的抑制作用。咪唑乙烟酸(30 g/hm2)与二甲戊灵(495 g/hm2)混用,对苜蓿的药害显著降低。苗后施用除草剂对苜蓿的安全性与叶龄密切相关。咪唑乙烟酸以30~60 g/hm2剂量在苜蓿3叶期施用,对苜蓿安全;在120 g/hm2用量下,对5叶期的苜蓿无明显药害。乳氟禾草灵(130~260 g/hm2)和丙炔氟草胺(75~150 g/hm2) 无论是3叶期还是5叶期施用,对苜蓿幼苗都有严重的药害。与咪唑乙烟酸单用时比较,药液中添加1.0 mL/L 的平平加-15和AM-100及5.0 mL/L的SDP,对苜蓿幼苗生长无明显影响。     

不同种源地文冠果叶片解剖结构比较及抗旱性分析

文中利用常规石蜡制片法,以内蒙古伊金霍洛旗乌兰木伦镇的文冠果人工林为研究对象,对引种在该地的8个种源地的文冠果叶片解剖结构进行了详尽的观察和测量。结果表明:文冠果叶表皮具有较厚的角质层和细胞壁;叶肉组织分化明显,具有发达的输导组织和维管束鞘伸展区;在中脉区域普遍存在黏液细胞和含晶细胞。选取叶片总厚度、上、下表皮细胞厚度、上、下角质层厚度、栅栏组织厚度、海绵组织厚度、栅栏组织与海绵组织厚度之比8个抗旱性指标,利用方差分析和LSD多重比较,结果表明:文冠果叶片抗旱指标的灵敏度大小顺序依次是:栅栏组织和海绵组织厚度之比>海绵组织厚度>下角质厚度。叶片结构上体现的抗旱性顺序是:呼伦贝尔阿荣旗>山东泰安=伊旗乌兰木伦>阿旗坤都林场>翁牛特旗经济林场>内蒙古农业大学>敖汉旗双井子林场>磴口。     

萘二甲酐减轻咪唑乙烟酸对向日葵药害的解毒效果及解毒机理研究

采用模拟咪唑乙烟酸土壤残留的试验方法,以向日葵为生测试材进行盆栽试验,研究萘二甲酐减轻咪唑乙烟酸对向日葵土壤残留药害的解毒效果和机理。结果表明,咪唑乙烟酸用量为有效成份25g(a.i.)/hm2对向日葵有一定的药害。萘二甲酐对咪唑乙烟酸药害有一定的缓解作用,萘二甲酐+咪唑乙烟酸处理的向日葵株高明显高于咪唑乙烟酸25g(a.i.)/hm2处理,而株鲜重却明显降低。萘二甲酐和咪唑乙烟酸都能导致向日葵苗的氨基酸含量发生变化,与咪唑乙烟酸25g(a.i.)/hm2处理相比,萘二甲酐加入咪唑乙烟酸后,使3种氨基酸含量比咪唑乙烟酸处理增加,2种氨基酸含量降低,12种氨基酸含量和氨基酸总量没有变化,可以认为氨基酸含量的变化是萘二甲酐对咪唑乙烟酸的解毒因素之一。萘二甲酐和咪唑乙烟酸对向日葵苗中谷胱甘肽(GSH)含量和谷胱甘肽-S-转移酶(GSTs)活力均有不同程度的影响,萘二甲酐+咪唑乙烟酸处理的共同作用可使向日葵苗体内GSH含量显著增加,而GSTs活力却有较大幅度降低。     

咪唑乙烟酸降解菌的分离、鉴定及降解特性研究

采用高压富集方法,从生产咪唑乙烟酸农药厂排污口污泥中分离得到1株咪唑乙烟酸高效降解菌P14,根据菌株形态、生理生化特性及16S rDNA分析,鉴定该菌株为哈夫尼希瓦氏菌Shewanella hafniensis。初步研究了其在不同条件下对咪唑乙烟酸的降解性能。结果表明:在以咪唑乙烟酸为唯一碳源的无机盐培养基中,当咪唑乙烟酸初始质量浓度为100 mg/L、培养温度为30 ℃、pH值6.0、接种量7%时,菌株P14对咪唑乙烟酸的降解效果最佳,3 d内的降解率可达92%,因而可以此作为菌株P14降解咪唑乙烟酸的最佳条件。外加不同碳源时,P14菌株对咪唑乙烟酸的降解率呈现不同程度下降,其中柠檬酸钠对P14菌株降解效果影响较小。     

50g/L咪唑乙烟酸水剂对大豆田杂草防效及安全性研究

选用50g/L咪唑乙烟酸水剂除草剂对大豆进行苗后茎叶喷雾处理.研究其对大豆田杂草的防效及对大豆的生长发育、产量和品质的影响.结果表明:50g/L咪唑乙烟酸水剂对大豆生长安全用量为200mL/667m2以内;50g/L咪唑乙烟酸水剂施药用量为300mL/667m2、400mL/667m2、600mL/667m2,除草彻底,但大豆叶片受害,产生大片药斑,生长受到严重抑制.但在生长后期基本都能恢复正常生长.     

咪唑乙烟酸对谷子生理特性及产量构成的影响

为探究咪唑乙烟酸对抗性及常规谷子品种生理特性及产量构成的影响及其抗性机理,以抗咪唑乙烟酸谷子品种冀谷35和常规谷子品种冀谷38、冀谷41、晋谷21、晋谷59、长农44、龙谷39和中谷9为研究对象,采用盆栽及田间试验比较其苗期生理特性和产量构成对咪唑乙烟酸的响应.盆栽试验结果显示:咪唑乙烟酸按有效成分93.5 g/hm2...     

豆科3属6种植物叶片特征比较研究

运用石蜡切片技术和叶片解离技术对豆科6种植物的叶片特征进行研究,利用光学显微镜观察了3属6种豆科植物的叶表皮及叶片解剖结构,统计并测量了表皮细胞形状、垂周壁式样、表皮细胞面积、气孔大小、气孔密度、气孔指数、表皮厚度、叶片厚度、叶肉厚度、栅栏组织厚度、海绵组织厚度等相关的特征,并分析了叶片特征在种属之间存在的异同。结果表明:3属6种植物的气孔在上下表皮均有分布,气孔类型为不规则型,气孔形状均为椭圆形。表皮细胞形状、垂周壁式样、气孔密度、气孔指数、下表皮厚度、海绵组织厚度等指标在种属之间存在差异且具有一定的规律。分析显示:锦鸡儿属两种植物与草木樨属两种植物亲缘关系较近。     

降雨及助剂对咪唑乙烟酸药效的影响

以苘麻Abutilon theophrasti为测试植物,研究了施药后降雨和助剂对咪唑乙烟酸除草活性的影响。结果表明,咪唑乙烟酸有较好的耐雨性,药后2 h内无降雨,可保持相当的防效,药后4~8 h内无降雨,与无降雨的没有显著差异。添加非离子表面活性剂能明显提高咪唑乙烟酸的除草活性。其中增效作用从大到小依次为:AM-100＞PPJ-15＞OP-10＞SDP,咪唑乙烟酸的IC50值分别比未加助剂处理的下降了33.6%、35.4%、29.5%和17.1%。咪唑乙烟酸的用量越低,助剂的增效作用越明显。     

空气湿度对灰霉菌侵染番茄叶片组织结构分析及抗氧化系统的影响

 空气湿度对番茄灰霉病的发生有显著性影响。为了探明空气湿度对灰霉菌侵染番茄叶片的过程与机理,本研究以‘金棚14-6’番茄为材料,观察分析了高空气相对湿度(80%~95%)和低空气相对湿度(65%~80%)对灰霉菌侵染番茄叶片表型变化、细胞学差异、形态结构变化、活性氧含量和抗氧化酶的影响。结果表明:高湿接种60 h大量芽管伸长出现在叶片下表皮细胞并分化菌丝,叶肉细胞间隙分布了大量的菌丝并伴随病斑出现,灰霉菌在60 h完成侵染;低湿接种108 h芽管伸长出现在叶片下表皮并分化菌丝,叶肉细胞间隙有少量菌丝分布,没有明显病斑出现。随着灰霉菌的侵染,低湿与高湿相比栅栏组织和海绵组织结构从整齐紧密变为排列疏松的时间滞后;高湿和低湿处理的叶片厚度、栅栏组织和海绵组织厚度均呈先上升后下降的变化趋势,侵染后期低湿处理的叶片组织结构厚度显著高于高湿。随着接菌时间延长,高湿和低湿的活性氧含量和抗氧化酶活性处于相对活跃的调整、适应的变化过程,大致呈先上升后下降趋势,而对照和接菌相比无显著差异,变化趋势维持在基本的振幅上。研究显示灰霉菌发生的环境条件:湿度80%~95%和侵染完成时间60 h,即控制高空气湿度的持续时间在60 h内。这为设施内番茄灰霉病的湿度调控防治提供了理论基础。     

表面活性剂、喷液量及杂草叶角对普杀特喷后附着量的影响

表面活性剂、喷液量及杂草叶角对普杀特在非敏感杂草马唐叶片上的喷后附着量有明显的独立影响和交互影响,其中表面活性剂的影响最大。供试的6种非离子型表面活性剂均因显著降低了普杀特药液的表面张力从而显著提高了其在马唐叶片上的喷后附着量,其中ScOil和Silwet—L77对其提高幅度最大;普杀特在马唐叶片上的喷后附着量随着喷液量的减少逐步增加,但在0—90°范围内随着马唐叶角的减小而减少,其由于喷液量的增大或马唐叶角的减小而引起的下降量,可通过加入非离子型表面活性剂而得到补偿,加入非离子型表面活性剂配合下午微液量(90L/ha)喷施,可望最大限度地增加普杀特在其非敏感杂草叶片上的喷后附着量,进而提高其药效,降低其使用成本和减少其在土壤中的残留。     

Drought-induced anatomical changes in radish (Raphanus sativus L.) leaves supplied with trehalose through different modes

Leaf anatomical changes were appraised in exogenously applied trehalose of radish (Raphanus sativus L.) plants grown under nonstress (well-watered) and water stress (60% field capacity) conditions. Two cultivars of radish namely, Manu and 40-Day, were grown in a pot experiment at the Botanical Garden, GCUF, Pakistan. Plants were subjected to 60% field capacity conditions after three weeks of germination. Trehalose (25 mM) was applied to the radish plants through two different modes (foliar and presowing). After 2 weeks of foliar-applied trehalose, the leaves were excised from the plants for studying different anatomical features. Water stress caused a significant reduction in the leaf vascular bundle area, leaf midrib thickness (only in cv. Manu), leaf parenchyma cell area, and the number of vascular bundles in both radish cultivars, while water stress increased leaf epidermis thickness of both radish cultivars. Exogenously applied trehalose through both (presoaking and foliar spray) modes was effective in increasing leaf epidermis thickness, vascular bundle area, midrib thickness, and number of vascular bundles in both radish cultivars under water stress and nonstress conditions. Foliar-applied trehalose was more effective in increasing midrib thickness in both radish cultivars under both water regimes. Of both cultivars, the performance of cv. Manu was better in leaf epidermis thickness, leaf midrib thickness, vascular bundle area, leaf parenchyma cell area, and the number of vascular bundles. Overall, exogenous application of trehalose through both modes was effective in triggering leaf anatomical changes under different water regimes.     

麦冬草对草甘膦耐药性的形态学机制

麦冬、土麦冬和阔叶土麦冬都对草甘膦具有较高的天然耐药性,其耐药性的主要机制是由于EPSPS基因结构差异、基因多拷贝以及高表达量,但是,靶标机制并不能完全解释阔叶土麦冬的耐药性最高,麦冬的耐药性最低,土麦冬居于中间。为了进一步揭示其耐药性的非靶标机制,采用光镜和扫描电镜观察了麦冬、土麦冬和阔叶土麦冬的叶表皮显微结构,发现麦冬、土麦冬和阔叶土麦冬的气孔主要分布于叶片下表皮,气孔密度分别为37.6、36.15和23.92个/mm~2。但是,土麦冬和阔叶土麦冬的气孔在叶片上表皮也有分布,并且阔叶土麦冬上表皮的气孔明显多于土麦冬。麦冬草气孔带和非气孔带细胞在细胞长度、面积和长宽比等方面均存在差异。麦冬气孔周围的表皮细胞平周壁具明显瘤状突起,导致气孔下陷;土麦冬气孔周围的表皮细胞平周壁呈波浪状突起,使气孔略下陷;阔叶土麦冬气孔周围的表皮细胞平周壁基本无突起,气孔下陷不显。这些结构特征差异可能与麦冬草对草甘膦的耐药性差异有一定的相关性。     

西葫芦银叶病叶片的光合生理与解剖学特征

 使用CI-310型便携式光合作用测定系统对西葫芦银叶病叶片的光合生理进行了测定。结果表明:西葫芦感染银叶病后,其一日内不同时段的光合速率(Pn)都较正常叶明显下降,轻病叶下降幅度为5.6%~30.2%,重病叶下降幅度为21.7%~52.5%,并且不同处理Pn的最高峰期也不尽一致,正常叶的最高峰期为10点钟,轻病和重病叶的最高峰期均为8点钟。西葫芦轻、重银叶病病叶的气孔限制值(Ls)均较正常叶减少,轻病叶减少幅度为5.3%~23.5%,重病叶减少幅度为22.0%~58.8%。轻、重病叶和正常叶之间的气孔导度(Gs)、胞间CO₂浓度(Ci)差异不明显,蒸腾速率(Tr)的变化无规律性。经测定,西葫芦轻、重病叶的叶绿素a、b及叶绿素总量都较正常叶减少,轻病叶叶绿素总量减少9.97%,重病叶叶绿素总量减少18.21%。西葫芦重病叶的鲜、干重较正常叶减少,而轻病叶的鲜、干重较正常叶增加。对西葫芦银叶病叶片的解剖学特征观察发现,正常叶上表皮细胞为扁平状,致密排列;而病叶上表皮细胞则变为球状,疏松排列,并且上表皮与栅栏细胞之间出现轻微的间隙。病叶上表皮厚度占叶片厚度的比例明显增加,栅栏组织厚度占叶片厚度的比例略有减少。     

竹叶花椒-飞龙掌血嫁接树表型及生理性状的抗旱响应

为探究飞龙掌血作砧木嫁接竹叶花椒后的抗旱响应机制,以飞龙掌血、竹叶花椒实生树及两者嫁接树为研究对象,对比分析其根系特征、叶片解剖结构、光合色素及生理指标上的差异,并测定产量。结果表明：飞龙掌血1年生实生苗根系各指标均显著高于竹叶花椒;嫁接树叶片栅栏组织、海绵组织厚度相比竹叶花椒显著增加了46.57%和35.38%,栅海比和叶肉紧密度分别提高了9.24%和21.82%;与竹叶花椒相比,嫁接树叶片叶绿素a、叶绿素b及类胡萝卜素的含量各显著增加了13.5%、87.3%和33.5%;同时,嫁接树叶片的SOD和POD活性相比竹叶花椒分别提高了22.1%和6.4%,MDA含量降低了4.6%;叶片各光合色素含量与栅栏组织厚度呈显著正相关关系,而MDA含量与其余指标呈显著负相关关系(除海绵组织厚度以外);嫁接树的单位投影面积产量相比竹叶花椒提高了34.1%。可见,该嫁接组合可以应用于竹叶花椒抗旱砧木的选育和推广实践。     

Protoporphyrinogen oxidase-inhibiting activity of the new,wheat-selective isoindoldione herbicide,cinidon-ethyl

Cinidon-ethyl (BAS 615H) is a new herbicide of isoindoldione structure which selectively controls a wide spectrum of broadleaf weeds in cereals. The uptake, translocation, metabolism and mode of action of cinidon-ethyl were investigated in Galium aparine L, Solanum nigrum L and the tolerant crop species wheat (Triticum aestivum L). When plants at the second-leaf stage were foliarly treated with cinidon-ethyl equivalent to a field rate of 50 g ha⁻¹ for 48 h, the light requirement for phytotoxicity and the symptoms of plant damage in the weed species, including rapid chlorophyll bleaching, desiccation and necrosis of the green tissues, were identical to those of inhibitors of porphyrin synthesis, such as acifluorfen-methyl. The selectivity of cinidon-ethyl between wheat and the weed species has been quantified as approximately 500-fold. Cinidon-ethyl strongly inhibited protoporphyrinogen oxidase (Protox) activity in vitro, with I₅₀ values of approximately 1 nM for the enzyme isolated from the weed species and from wheat. However, subsequent effects of herbicide action, with accumulation of protoporphyrin IX, light-dependent formation of 1-aminocyclopropane-1-carboxylic acid-derived ethylene, ethane evolution and desiccation of the green tissue, were induced by cinidon-ethyl only in the weed species. After foliar application of [¹⁴C] cinidon-ethyl, the herbicide, due to its lipophilic nature, was rapidly adsorbed by the epicuticular wax layer of the leaf surface before it penetrated into the leaf tissue more slowly. No significant differences between foliar and root absorption and translocation of the herbicide by S nigrum, G aparine and wheat were found. After foliar or root application of [¹⁴C]- cinidon-ethyl, translocation of ¹⁴C into untreated plant parts was minimal, as demonstrated by combustion analysis and autoradiography. Metabolism of [¹⁴C]cinidon-ethyl via its E-isomer and acid to further metabolites was more rapid in wheat than in S nigrum and G aparine. After 32 h of foliar treatment with 50 g ha⁻¹ of the [¹⁴C]-herbicide, approximately 47%, 36%, and 12% of the absorbed radioactivity, respectively, were found as unchanged parent or its biologically low active E-isomer and acid in the leaf tissue of G aparine, S nigrum and wheat. In conclusion, cinidon-ethyl is a Protox-inhibiting, peroxidizing herbicide which is effective through contact action in the green tissue of sensitive weed species. It is suggested that a more rapid metabolism, coupled with moderate leaf absorption, contribute to the tolerance of wheat to cinidon-ethyl. © 1999 Society of Chemical Industry     

Differential influence of herbicide treatments on activity and kinetic parameters of C4 photosynthetic enzymes from Zea mays

The recommended field dose of rimsulfuron, imazethapyr, alachlor, atrazine or fluometuron differentially reduced shoot fresh and dry weight of 10-day-old maize seedlings as well as leaf protein content during the following 12 days. These reductions seemed consistent during the whole period with fluometuron, atrazine and alachlor but appeared to be nullified by the 5th day of treatment with rimsulfuron and imazethapyr. On the other hand, all herbicides mostly provoked significant inhibitions in specific activities of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31), malate dehydrogenase (MDH, EC 1.1.1.82), pyruvate phosphate dikinase (PPDK, EC 2.7.9.1) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1.39) in leaves during the first 2 days. Thereafter, the inhibition was recovered in samples treated with rimsulfuron and imazethapyr, leveled off with alachlor but consistently augmented with atrazine and fluometuron. The kinetic characterization showed that rimsulfuron or imazethapyr unchanged V_max of all enzymes in vitro, however, V_max of PEPC, PPDK and Rubisco were decreased in vivo. Nevertheless, atrazine or fluometuron substantially reduced V_max of all enzymes while alachlor showed a reduction in this value of PEPC, MDH and Rubisco. Thus atrazine, fluometuron and, to a lower extent, alachlor reduced concentrations of all enzymes as well as rimsulfuron and imazethapyr for only Rubisco. On the contrary, K_m values of all enzymes were progressively increased by all herbicides indicating that the different herbicides altered the structural integrity of all enzymes. These findings conclude that rimsulfuron or imazethapyr competitively inhibited MDH but revealed mixed inhibition to PEPC, PPDK and Rubisco. Atrazine or fluometuron revealed mixed inhibitions to all enzymes whereas alachlor seemed to be either a competitive inhibitor to PPDK or a mixed inhibitor to PEPC, MDH and Rubisco.