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1.
植物种群构件理论认为,植物种群构件生物量是植物与环境因素共同作用的结果。以共同分布于吉尔吉斯斯坦南部和中国新疆北部荒漠环境中的紫翅猪毛菜(Salsola affinis)和散枝猪毛菜(Salsola brachiata)为研究材料,从构件水平对2种猪毛菜种群构件的生物量进行了定量分析。结果表明:2个分布区的2种猪毛菜属植物生长与分配均有规律性的同速生长,各种群构件生物量的比例有差异(P0.01);分布于新疆的2种猪毛菜各构件生物量和个体总生物量均比分布于吉尔吉斯斯坦的大(P0.01);紫翅猪毛菜的各构件生物量和个体总生物量比散枝猪毛菜大(P0.01)。这可能是因为新疆和吉尔吉斯斯坦地理和气候等条件差异以及这2种猪毛菜对特殊环境的适应机制不同所致。因此,两者之间的关系适合于植物种群构件理论。 相似文献
2.
黄山球孢白僵菌野生种群流行菌株的28S rDNA Ⅰ型内含子分析 总被引：1，自引：0，他引：1
通过4对引物,对采自黄山的40株球孢白僵菌菌株进行28S rDNA I型内含子分析,以探讨黄山自然种群的遗传结构及流行菌株类型。结果显示,在黄山球孢白僵菌自然种群中,存在着13种不同的内含子单倍型,显示出在黄山小范围内的球孢白僵菌种群也存在着丰富的遗传多样性。不同单倍型在种群中所占的比例不同,其中BBBA型占据主导地位,为37.5%,ABAA型和ABBA型次之,分别为15%和12.5%,而BABA等7种单倍型则各仅占2.5%,反应出不同的遗传背景的菌株具有不同的遗传稳定性与环境适应性。数据同时显示,同核体菌株在黄山球孢白僵菌自然种群中的比例为82.5%,显示出同核体在遗传稳定性上优于杂核体,但同时,17.5%的杂核体比例也显示出准性生殖在球孢白僵菌种群中的普遍性。 相似文献
3.
准噶尔荒漠两种猪毛菜果实扩散特性研究 总被引：1，自引：0，他引：1
《干旱区资源与环境》2017,(7):151-155
植物的扩散能力受扩散体数量和形态特征、扩散方式和扩散距离等因素的影响。文中以分布于准噶尔荒漠的紫翅猪毛菜(Salsola affinis)和散枝猪毛菜(Salsola brachiata)为研究材料,对其扩散体形态特征及扩散特性进行了研究。实验结果表明:两种猪毛菜果实数量和株高、果实生物量和植株总生物量呈正相关;果实是该物种的扩散单元,风和水是其主要扩散媒介,风媒扩散属于近距离扩散,水媒扩散属于远距离扩散;果翅的大小对扩散具有显著影响。以上特征是该物种适应荒漠环境的重要因素。 相似文献
4.
为探究濒危植物东北岩高兰枝芽萌发、分枝和枝条生长特性,以大兴安岭北部满归林业局高地林场石质山地东北岩高兰为研究对象,在疏林-林缘-石隙连续样带设置标准地,分别均等选取标准株和标准枝,调查枝芽形成的时间、类型、着生部位、萌发时间、1a枝长和枝径、样株1~5a枝的叶和不定根生长情况。结果表明:1)东北岩高兰越冬枝芽5月中下旬萌发,顶芽和近枝顶腋芽具早熟性,可在当年8月中下旬萌发,秋梢长度0.5~1.0cm,形成新枝的顶芽在密集叶包裹下越冬。2)顶端优势具多变性,形成"一优多强顶端优势"或"多强顶端优势",以适应多变的极端生境拓展种群生存空间。3)枝芽萌发抽枝分为5种类型,非近枝顶侧枝为偶见;各类型分枝率1.00~6.44,新枝数量差异较大。顶芽萌发对侧枝、特别是非近枝顶侧枝的抽生具有一定的抑制作用。4)3a枝匍匐生长且逐渐生根成不同匍匐茎克隆个体,形成与贫瘠生境中不同生存资源微生境相协调的生长发育响应策略,保证种群在总体干旱、贫瘠、多风极端生境下的不同微生境中生息繁衍。 相似文献
5.
盐分、温度对猪毛菜种子萌发的影响 总被引：6，自引：4，他引：2
通过对浆果猪毛菜和钠猪毛菜种子在不同盐分、温度环境下的萌发过程与对策研究,结果表明:2种猪毛菜种子萌发的最佳温度约为25 ℃.浆果猪毛菜在蒸馏水中的萌发速度低于钠猪毛菜.浓度低于0.2 mol/L的NaC1溶液对萌发的影响不大;随NaCl浓度增高,浆果猪毛菜和钠猪毛菜种子萌发率降低.一定的盐分胁迫不影响种子萌发潜力,其萌发恢复率随原处理溶液抑制程度的增加而增加.同时,讨论了2种猪毛菜种子萌发特性与环境的关系. 相似文献
6.
为了探究不同年代的大丽轮枝菌(Verticillium dahliae Kleb.)菌株生物学特性和遗传多样性方面的差异,本文以我国黄河流域和长江流域主产棉区6个省的不同年代大丽轮枝菌菌株为研究对象,观察培养性状,测定致病类型(致病力、落叶型),同时采用ISSR指纹图谱分析其遗传多样性。结果显示,不同年代大丽轮枝菌之间菌丝生长速率无显著差异,但菌核型菌株所占比例有减少趋势;2007~2009年和2017年的菌株全部为落叶型菌株,而1983~2000年的菌株中落叶型菌株仅占28.6%,表明随着年代的推移,黄河流域和长江流域的落叶型菌株所占比例呈上升趋势;不同年代菌株之间致病力存在显著差异,1983~2000年、2007~2009年和2017年的菌株中强致病力类型菌株分别占21.4%、25.0%和38.9%,仅有的5株弱致病力类型菌株均为1983~2000年的菌株;与2000年后的菌株相比,1983~2000年的菌株,Nei′s基因多样性指数为0.205 1,Shannon信息指数为0.299 0,表现出更丰富的多样性,利用NTSYS软件和Structure软件对ISSR指纹图谱进行聚类分析,两种方法均将所有供试菌株分为4个类群,且聚类结果与致病力和不同年代之间均具有一定的相关性,与地理来源无明显相关性。本研究结果表明,过去30年间我国黄河流域和长江流域棉田黄萎病菌落叶型和强致病力类型菌株所占比例逐渐升高,且不同年代和不同致病力的菌株在遗传上有差异,为进一步探究大丽轮枝菌的遗传与进化奠定了基础。 相似文献
7.
为了探究不同年代的大丽轮枝菌(Verticillium dahliae Kleb.)菌株生物学特性和遗传多样性方面的差异,本文以我国黄河流域和长江流域主产棉区6个省的不同年代大丽轮枝菌菌株为研究对象,观察培养性状,测定致病类型(致病力、落叶型),同时采用ISSR指纹图谱分析其遗传多样性。结果显示,不同年代大丽轮枝菌之间菌丝生长速率无显著差异,但菌核型菌株所占比例有减少趋势;2007~2009年和2017年的菌株全部为落叶型菌株,而1983~2000年的菌株中落叶型菌株仅占28.6%,表明随着年代的推移,黄河流域和长江流域的落叶型菌株所占比例呈上升趋势;不同年代菌株之间致病力存在显著差异,1983~2000年、2007~2009年和2017年的菌株中强致病力类型菌株分别占21.4%、25.0%和38.9%,仅有的5株弱致病力类型菌株均为1983~2000年的菌株;与2000年后的菌株相比,1983~2000年的菌株,Nei′s基因多样性指数为0.205 1,Shannon信息指数为0.299 0,表现出更丰富的多样性,利用NTSYS软件和Structure软件对ISSR指纹图谱进行聚类分析,两种方法均将所有供试菌株分为4个类群,且聚类结果与致病力和不同年代之间均具有一定的相关性,与地理来源无明显相关性。本研究结果表明,过去30年间我国黄河流域和长江流域棉田黄萎病菌落叶型和强致病力类型菌株所占比例逐渐升高,且不同年代和不同致病力的菌株在遗传上有差异,为进一步探究大丽轮枝菌的遗传与进化奠定了基础。 相似文献
8.
不同类型沙地长穗虫实的繁殖分配及其与个体大小的关系 总被引：3，自引：0，他引：3
研究了不同类型沙地一年生植物长穗虫实的繁殖分配及其与个体大小的关系.结果表明:①不同类型沙地长穗虫实的个体大小、繁殖器官大小、单株种子数以及株高等其他地上部分特征均表现出极显著的差异性,其大小排列顺序为:固定沙地>半固定沙地>流动沙地,即表现出随沙面的固定而逐渐增大的趋势;②不同类型沙地虫实繁殖分配、单株种子重和种子均重也不相同,其差异程度从不显著到极显著不等;③不同类型沙地虫实个体大小与繁殖器官大小均呈极显著的正相关关系,个体大小与繁殖分配在不同类型沙地呈负相关关系,其中在流动沙地和固定沙地上达到显著水平;④个体大小与单株种子数、单株种子重之间存在正相关关系,但流动沙地相关程度较低;⑤不同类型沙地上虫实繁殖分配具体表现为,流动沙地为34.9%,固定沙地和半固定沙地大于50%,即随着沙面固定程度的增加,一年生植物种虫实倾向于将更多的资源和能量用于繁殖生长.这一结论不仅有助于分析该植物对沙生生境的适应对策,也有助于对种群繁殖对策理论问题的深入探讨. 相似文献
9.
异色瓢虫色斑多样性调查及各地十九斑变型COI基因系统进化分析 总被引：1，自引：1，他引：0
异色瓢虫Harmonia axyridis(Pallas)是一种具有丰富色斑的捕食性天敌,主要捕食烟粉虱、蚜虫和粉蚧等小型害虫,复杂的地理环境会导致异色瓢虫形成不同的色斑型。为了解我国异色瓢虫的色斑多样性,通过采集、调查与分析5个省份异色瓢虫主要色斑类型、黄底型各色斑类型的比例及斑点出现频率,以17个地区数量较多的异色瓢虫十九斑变型为研究对象,运用细胞色素氧化酶亚基I(COI)基因序列比对的方法,分析了各瓢虫种群之间的系统进化关系。结果表明,5个省份的异色瓢虫种群中,黄底型数量比例显著高于黑底型,黑底型中黑缘型数量比例极少。内蒙古贺兰山地区的黄底型异色瓢虫中,十九斑变型所占比例最大,占28.77%;其中斑点3出现的频率最高,占84.43%,半斑出现的频率最低,占28.77%。系统进化分析表明,除了云南异色瓢虫种群与其它地区差异较大外,其它16个地区的异色瓢虫十九斑变型之间具有很高的同源性。推测影响异色瓢虫形成不同色斑的关键因素很有可能是遗传基因之外的其它因素。 相似文献
10.
为明确田间甜菜夜蛾Spodoptera exigua幼虫产生绿色型和黑化型的色型分化原因,在田间系统调查黑化型幼虫所占比例及其与虫口密度的关系,在室内测定不同饲养密度对甜菜夜蛾幼虫色型分化的影响和色型分化敏感龄期,以及视觉、嗅觉和触觉对幼虫色型分化的影响。结果表明,田间甜菜夜蛾1~3龄幼虫均为绿色型,4~5龄幼虫同时存在绿色型和黑化型;在甘蓝上,4龄幼虫中黑化型个体所占比例为21.14%,5龄幼虫中黑色型个体所占比例为28.53%,在辣椒上,4龄幼虫中黑化型个体所占比例为20.54%,5龄幼虫中黑色型个体所占比例为33.88%。随着百株虫量的增加,甘蓝和辣椒上黑化型幼虫所占比例呈现升高趋势。室内研究发现,随着甜菜夜蛾幼虫饲养密度的增加,黑化型幼虫占比显著升高,当饲养密度达到5头/盒时趋于稳定,体色等级指数为3.47; 3龄是甜菜夜蛾幼虫色型分化的敏感龄期;视觉和嗅觉刺激对甜菜夜蛾幼虫黑化无显著影响,而触觉刺激显著促进幼虫黑化,甘蓝叶片碎片和白色聚酯纤维的摩擦处理导致幼虫体色等级指数分别显著升高68.59%和71.79%,表明触觉刺激信号对甜菜夜蛾的密度依赖性黑化有显著促进作用。 相似文献
11.
猪毛菜属(Salsola L.)是藜科中最大的属之一,在新疆植物区系和植物资源开发利用中占有重要地位。通过对新疆猪毛菜属32种植物的果时花被片附属物和叶片解剖结构的特征及其地理分布的分析,结果表明:①果期花被片附属物可分为两类,其中具翅状附属物的形态更加丰富;②得到4种叶片解剖结构类型,包括C3-SYMP型、C3-C4中间型、C4-SALS+H型和C4-SALS-H型。依据叶片解剖结构类型判断,新疆猪毛菜属中C4植物占绝大多数;③在新疆分布的猪毛菜属种类以草本植物居多,其生境主要以旱生和盐生环境为主;④猪毛菜属植物分布在新疆的6个地理分布地区,其中以准噶尔亚地区分布最多,塔城伊犁亚地区分布次之;⑤新疆猪毛菜属植物与国外邻近地区的共有种明显多于国内邻近地区。 相似文献
12.
Teresa NAVARRO 《干旱区科学》2021,13(9):962-976
The ability of plants to safely retain seeds in the mother plant is an adaptive mechanism described in many desert plants. However, research about delayed seed dispersal species in the desert of the United Arab Emirates (UAE) is lacking. This study aims to identify these delayed seed dispersal species and assess the relationships of the presence of delayed seed dispersal with plant growth form, habit, spatial dispersal, antitelechoric mechanism, and seed release time. The relationships between the presence of delayed seed dispersal and the above studied traits were assessed by using the Pearson Chi-square test and Nonlinear Principal Components Analysis (NLPCA). Results showed that a total of 46 delayed seed dispersal species were recorded (15.0% of 307 studied species) and the highest incidence occurred in the Fabaceae family (17.4%). Delayed seed dispersal species were predominantly perennial plants (73.9%) with spatial restricted dispersal (67.4%), which released seed in the dry season (45.7%). The dominant groups of delayed seed dispersal species were persistent fruits species and synaptospermy (28.3%). All graminoids showed persistent lignified fruits, while prostrate annuals were basicarpic species with myxospermy. Sandy habitats had the highest number of delayed seed dispersal species (54.3%), whereas salt flats had the lowest (23.9%). In the desert of the UAE, delayed seed dispersal species spread seeds until the end of the dry and windy season, thus breaking seed dormancy at this time and ensuring seed germination in the next arrival of the rainy season. This morphological and ecological adaptation of delayed dispersal species is essential to the survival and sustainable development of vegetation in desert environments. 相似文献
13.
The mode of infection ofColletotrichum musae, the main causal agent of tip rot of banana fruits in the Jordan Valley, was investigated. Immature, apparently healthy banana fruits cv. Dwarf Cavendish were inoculated by spraying spore suspensions on the distal end of the fruit. A correlation was found among type of flowers, age of fruits at inoculation time, concentration of spores in the inoculum, and the development of tip rot in the fruits. An infection rate of 100% was obtained with suspensions at a concentration of at least 5x104 spores/ml on fruit with persistent flower parts, not older than 3 weeks after the curling of the hand bract. On fruits with deciduous flower parts, only inoculations of very young fruits still under bracts was successful. Penetration of the fungus through the perianths was assessed. Virulent inoculum was found to be present in the plantation; 100% infection was obtained by using a suspension prepared from dry leaves and debris collected around banana plants. 相似文献
14.
The effects were investigated of fruit maturity and duration of wetness on infection of apple fruits by Venturia inaequalis , and subsequent scab development. Incubation rate (inverse of median incubation period) increased linearly with increasing temperature (5–20°C) on detached 5-week-old fruits of cv. Royal Gala. Fruits were highly susceptible in the early stages of development, but became increasingly resistant as they matured. Inoculation of attached 12-week-old and detached near-mature fruits did not result in any lesions, while inoculation of attached 4-, 5-, 7- and 9-week-old fruits resulted in various levels of infection. Fruits of cv. Mondial Gala were more susceptible than those of cv. Cox's Orange Pippin. On cv. Mondial Gala, a wet period of 9 h resulted in ≈ 90% infection of 4-week-old fruits, but only 9% infection of 9-week-old fruits. Numbers of scab lesions on an apple generally followed a Neyman type A rather than a Poisson distribution, indicating a certain degree of aggregation of lesions on a fruit. A two-parameter generalization of the Poisson model described the observed incidence–density relationship well. A longer duration of wetness was required to result in a similar level of scab infection on old fruits to that on young fruits. On cv. Mondial Gala, wet periods of 9 and 32 h were required for ≈ 90% incidence of fruit scab on 4- and 7-week-old fruits, respectively. A mathematical model was developed to relate the incidence of fruit scab to duration of wetness and fruit maturity. The potential use of these results in practical disease management is discussed. 相似文献
15.
Salsola australis, like other agricultural weed species of the Salsola genus, produces a mobile seedbank. Aspects of this mobile seedbank were investigated in three field trials, including total seed production, rate of seed shedding, rate at which seeds lose germinability and the distance and directionality of plant movement. Total seed production was highly variable (ranging from 138 to 7734 seeds per plant), but was directly related to aboveground plant biomass at maturity. Following senescence, mature plants broke free of their root system and the wind driven plants moved considerable distances (1.6–1247.2 m). Half of the mobile plants moved <100 m, as they became entangled with other S. australis plants within the stand. Seed shedding commenced before the plants became mobile and increased with movement, but was also related to the aging and weathering processes experienced by stationary or mobile plants. All plants retained a proportion of their seed in spite of movement, weathering and ageing of the plants, although germinability of retained seed dropped to <2% after 2 months. Salsola australis engages in broad scale seed dispersal similar to that observed in other species of the Salsola genus, allowing this species to maintain a high rate of invasion and range expansion. 相似文献
16.
A reliable, rapid and low-cost screening bioassay, based on measuring lesion sizes, rotten tissue weight and tissue colonization 1 week after the injection of a conidial suspension into the stem scars of mature green tomato fruits, was developed to assess the aggressiveness of Colletotrichum coccodes isolates. This protocol was compared with inoculation of either potato plantlets from in vitro multiplication, or ripe tomato fruits, using C. coccodes isolates from potato and from tomato. Aggressiveness to mature green tomato fruits was scored by measuring lesion size and weight at the scar end of the fruit, while colonization was measured in samples taken from the blossom end. Values of all three disease parameters were significantly higher ( ca . 3 times) with aggressive isolates of the pathogen than with less aggressive ones. High correlation levels among these three parameters were obtained. Also, the aggressiveness to mature green tomatoes was highly correlated with the aggressiveness to potato tissue culture plantlets. It was concluded that lesion size in inoculated tomatoes can be used as a sole measure for estimating the aggressiveness of C. coccodes isolates to either tomato or potato. 相似文献
17.
Evaluating susceptibility of almonds to anthracnose disease caused byCollectotrichum gloeosporioides
Susceptibility of almond fruit(Prunus dulcis (Mill.) Webb.) to anthracnose caused byColletotrichum gloeosporioides Penz.(=Gloeosporium amygdalinum Brizi) was investigated. Fruits were punctured, and a drop of spore suspension of the desired size and density was placed on the wound. Fruits were placed in a humid chamber for one week at 22°C. The diameter of the lesion of the infected fruits was used as an indicator of susceptibility. Disease development was found to be negatively correlated with the age of the fruit. The inoculation concentrations used in this research have no effect on the disease development, although the volume of the drop affected the size of the lesion to some extent. With constant, high relative humidity (saturation), the diameter of the anthracnose lesion increased by 1 mm per day, while under dry room conditions the increase was less than 0.5 mm per day. At 22°C lesions developed faster than at either 15° or 27°C. A detailed procedure for assessing sensitivity of fruit to anthracnose is described. This should enable improved comparison of susceptibility between genotypes and in different environments. 相似文献
18.
This study investigated the potential of seed transmission of Cape St. Paul wilt disease (CSPWD) in coconuts. PCR amplification was used to assess the distribution of phytoplasmas in parts of West African Tall (WAT) palms infected with CSPWD. Employing phytoplasma universal primer pair P1/P7 in standard PCR, or followed with a nested PCR using CSPWD–specific primer pair G813f/AwkaSR, phytoplasma infection was detected in the trunks, peduncles, spikelets, male and female flowers of four infected WAT coconut palms. Through nested PCR, phytoplasma was also detected in four of 19 embryo DNA samples extracted individually from fruits harvested from three of the four infected palms and was confirmed as CSPWD by cloning and sequencing. Subsequently, CSPWD phytoplasma was again detected in five of 33 embryos from nine infected palms, and in one of eight fruits from two symptomless palms. Fruits from infected palms recorded higher percentage germinations in two field nurseries (average of 71·0%) compared to fruits from healthy palms (average of 57·6%), and matured fruits that had dropped from infected palms showed the same levels of germination as those harvested directly from the palms. This indicates that infected fruits retain the ability to germinate whether harvested or dropped. No phytoplasmas were detected in any of the resulting seedlings and plantlets obtained through embryo in-vitro culture. Therefore, although phytoplasma DNA can be detected in embryos, there is as yet no evidence that the pathogen is seed transmitted through to the seedling to cause disease in progeny palms. 相似文献
19.
Translocation of 2,4-D, asulam and amitrole in water hyacinth 总被引：1，自引：0，他引：1
In glasshouse experiments foliar application or 14C-labelled herbicides to water hyacinth plants at the 4-leaf stage indicated that amilroie transport from the treated leaf blade was faster and greater than 2.4-D. but a little less than asulam. From the treated leaf 14·2, 25·9. 39·7. 44·5 and 51·8% of the recovered 14CNamitrole was translocated at intervals of 6 h. and 1. 3. 6 and 12 day., respectively. Both xylem and phloem transport of asulam and amitrole was evident, whereas 2.4-D moved only from ‘source to sink’. Movement of the herbicides from the mother to the connected daughter plant or vice versa was dependent upon the size of the latter. Maximum transport of these herbicides in either direction took place at the 2-leaf stage of daughter plants. With any increase or decrease in the number of leaves on daughter plants, the transport of herbicides was reduced. As an exception, daughter plant to mother plant movement of amilroie was maximum at the 1-leaf stage. After extraction, fractionation and TLC separation of foliage applied 14C-2.4-D 76–4 and 72·1% of the radioactivity was detected in the chloroform phase of the leaf extract at 3 and 6 day intervals, respectively. In another pot culture experiment, it was observed that after spraying the mother plants with 2.4-D-amine at 0–75 kg/ha the connected daughter plants at 1 to 4-leaf stages werckilled if the culture solution was contaminated while spraying, or by dying leaves. When contamination was totally avoided, the connected but unsprayed daughter plants at 3 to 4-feaf stages survived. 相似文献