974 resultados para CRANIAL ANATOMY
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早白垩世到早第三纪这段时期是松科早期起源和其后进行分支演化的关键时期。球果因为是重要的雌性生殖器官,而在松科演化问题上具有显著的研究价值。对早白垩世到早第三纪这段时间所发现的松科球果的研究经因一个半世纪的逐渐演变,现在划分为三个属:松属(Pinus),假南洋杉型属(Pseudoaraucaria),和松型球果属(Pityostrobus)。本文对采自辽宁义县早白垩世沙海组火山灰形成的凝灰质砂砾岩层中的一批硅化松科球果进行了详细的解剖学研究。将它们划分到松型球果属Pityostrobus中,并在此属下另立了4个新种:Pityostrobus hsuii, P. liaoningensis, P. yixianensis, P. borealis,以及五个暂时不能确切定种的类型。这些种以及类型根据鳞片基部树脂道的分布方式,划分为两类:一类包括Pityostrobus hsuii, P. liaoningensis,为在鳞片基部树脂道分布在鳞片迹的远轴面类型,它俩之间的区别主要在苞鳞复合体基部鳞片迹的形状上的显著差异,以及鳞片中上部树脂道的分布方式上的不同;另一类包括P. yixianensis以及与其相类似的四个类型和P. borealis以及一个与其相类似的类型,两个种在鳞片基部,树脂道分布在鳞片迹近轴面和远轴面,它们之间的差别主要在苞鳞复合体基部远轴面树脂道分布方式的不同而划分。通过与那些已发现的出产于欧洲和北美洲的种类进行对比,发现这批标本的结构性状上所体现出的多样性与欧美的标本有显著的不同。因此,在早白垩世,东亚为松科早期起源演化的一个重要中心。
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本论文系统回顾了无被果孢属的研究历史,讨论了无被果孢属的鉴定特征及种的划分依据,总结了无被果孢属已有种的特征及分布。在此基础上对山西太原西山煤田太原组7号煤层煤核及河北平泉杨树岭煤矿太原组火山凝灰岩中的无被果孢属进行了详细的解剖学研究,把它们与无被果孢属已有种进行了详细的对比后,共鉴定出二个新种和二个未定种。这二个新种的主要特征如下: 过渡无被果孢(新种)Achlamydocarpon intermedia sp. nov. 大孢子囊大约长6.0-10.0 mm,宽4.6 mm,高1.4mm,背腹扁状,具顶脊,两侧角明显, 近轴端开口。孢子囊壁复杂,分化为三层:最外层为单层柱状细胞层;中层1-2层细胞厚,细胞具深色内含物,壁薄;内层1-3层细胞厚,细胞壁强烈加厚。柱状层朝近轴端方向厚度加大。大孢子叶柄背脊不甚发育,具明显侧翼,侧翼的末端膨大并下垂使得柄的横切面略呈 “M”形。侧翼的宽度由近轴端向远轴端随孢子囊宽度的增加而增加,整体宽度大致保持为孢子囊的宽度的1/2左右。侧翼的近轴面具对称的厚壁组织区域。木质部束在近轴端为近等径状,向远轴端则变为略呈水平伸长状。通气组织发达,独立空腔结构贯穿孢子叶柄的整个长度。败育大孢子似乎具肿块结构。 本新种产于山西太原西山煤田太原组7号煤层煤核中。 2、平泉无被果孢(新种) Achlamydocarpon pingquanensis sp. nov 大孢子囊10.0-15.0 mm长,8.1 mm宽,3.0 mm 高。背腹扁,不具顶脊,两侧角明显,远轴端开口。壁复杂,分化为5层:最外层为薄壁细胞层,厚1-3层细胞;次外层为次生壁强烈增厚的细胞层,厚2-数层细胞;中层为具深色内含物的薄壁细胞层,厚2-数层细胞;次内层为与次外层相似的厚壁细胞层;内层为厚度达数个细胞的薄壁细胞层。孢子叶柄侧翼发育,宽度大于孢子囊宽度。背脊或龙骨很不显著。远轴面有时呈强烈的起伏不平状。大孢子囊底部与孢子囊柄连结部分由厚壁的细胞构成。不育组织垫结构较显著。功能大孢子扁缩,在近轴端发育较好,上表面具一突起结构。败育大孢子瘪缩,结构复杂,具明显肿块结构(?),瘤状肿块结构与败育孢子表面相连部分呈棒状。孢子叶柄近轴面不具有明显的厚壁组织区域;维管束由木质部束、维管束鞘及其所围成的空腔组成,但在远轴端仅剩下木质部束;通气组织发达,在维管束下方形成一独立空腔。 本新种分别产于山西太原西山煤田太原组7号煤层煤核和河北平泉杨树岭煤矿太原组火山凝灰岩中。 过渡无被果孢(新种)的特征介于欧美植物区的变异无被果孢类型和塔赫他间无被果孢类型之间。平泉无被果孢(新种)则与变异无被果孢类型较相近,但二者的大孢子囊壁的最外层完全不同:前者的是柱状细胞层,而后者的则由近等径的类似薄壁组织的细胞构成。二个未定种中,无被果孢(未定种 1)与过渡无被果孢(新种)很相似,区别在于前者的大孢子囊壁缺乏最外层的柱状细胞层以及孢子叶柄具明显的背脊或龙骨。无被果孢(未定种 2)则与塔赫他间无被果孢类型较接近。 根据华夏植物区和欧美植物区的化石材料和文献,探讨了保存不完整的大孢子囊-孢子叶复合体的远轴端和近轴端的判断方法:孢子囊较宽较高、孢子叶柄较为粗大、侧翼较发育、维管束较大、通气腔较发育的一端往往为远轴端,反之则为近轴端。 还讨论了无被果孢属一些构造的演化趋势: 1、孢子囊壁由简单向复杂或高度分化; 2、通气组织由不发达到高度特异化; 3、叶迹从微弱到显著,从简单到复杂; 4、败育大孢子从饱满到瘪缩,从表面平整到高度曲折,结构复杂化 5、大孢子四分体结合紧密度呈下降趋势
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本文回顾了八角科(Illiciaceae)的分类历史,对其现状进行了介绍,并提出了存在的一些问题,针对这些问题,我们对八角科及其近缘类群 [五味子科(Schisandraceae)和木兰科(Magnoliaceae)] 的木材解剖特征,以及对组成八角目(Illiciales)的八角科和五味子科的花被片表皮形态进行了研究,进一步确定了八角科在离生心皮类中的原始地位,且为其属的次级划分提供了更多的性状支持,更详尽地阐述了它与近缘类群间的系统学关系,确定了八角目的独立地位。 1 比较木材解剖学 在光学显微镜和扫描电子显微镜下,对八角科八角属(Illicium)2组19种1亚种43个材料、五味子科2属4种7个材料和木兰科1属3种4个材料的木材解剖结构进行了比较研究。 因八角科导管单独、多角形、密集、细长且具螺纹加厚,穿孔板梯状且细密,射线异形等特征,本文支持建立单属的八角科。在八角属内,由于八角组(Sect. Illicium)的导管分子密度较高和直径较窄,易损度为0.090,射线较高,而八角茴香组(Sect. Cymbostemon)的导管分子密度较低和直径较宽,易损度为0.194,射线较矮,因而本文支持将八角属分为八角组和八角茴香组,且八角组比八角茴香组原始。根据欧式距离,八角科与五味子科之间的相似性(d=4.690)比八角科与木兰科(d=4.899)之间的相似性大,本文支持建立八角目(Illiciales)。 2 花被片表皮比较形态学 在光学显微镜和扫描电子显微镜下,观察了八角科八角属2组11种20个样品、五味子科南五味子属(Kadsura)2亚属2组8种15个样品和五味子属(Schisandra)2亚属4组6种17个样品的花被片表皮形态特征。 首次报道了八角目2个科(八角科和五味子科)3个属(八角属、南五味子属和五味子属)植物花被片表皮细胞的形状、分泌细胞的形状及分布、气孔器的形状及分布、花被片表面的纹饰,在五味子科中发现2个新的性状(气孔对和环列型气孔)。 通过与八角目2个科3个属植物的叶表皮形态比较,发现花被片表皮气孔器外拱盖均为单层,与叶表皮气孔器外拱盖层数(常绿种类为双层和落叶种类为单层)之间没有相关性。通过对两性花、雌花和雄花花被片表皮观察,发现花被片表皮形态与花的性别之间没有相关性。通过对八角属、南五味子属和五味子属花被片表皮比较,发现五味子属花被片表皮形态比南五味子属花被片表皮形态表现出更多的衍生性状,南五味子属花被片表皮形态比八角属花被片表皮形态表现出更多的衍生性状;南五味子属花被片表皮形态与五味子属花被片表皮形态之间的相似性程度较大,与八角属花被片表皮形态之间的相似性程度较小,支持建立含南五味子属和五味子属的五味子科,支持建立只含八角属的八角科。
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山黑豆属Dumasia DC.隶属于豆科、菜豆族、大豆亚族,广泛分布于亚洲、非洲东南部的热带、亚热带地区以及大洋洲的巴布亚新几内亚地区,其中大多数种在我国均有分布。该属形态变异复杂,命名混乱,缺乏世界性的系统分类学研究基础。基于这样的背景,本论文通过开展形态学、解剖学、细胞学及孢粉学等方面的综合研究工作,对该属进行了全面的分类修订,对属内种间关系及地理分布格局进行了分析和探讨,结果如下: 1、形态学 在研究了大量腊叶标本和进行了野外考察的基础上,对山黑豆属植物的形态性状的变异式样进行了分析。该属植物的根系形态较为多样,可以作为划分种的辅助形状,分为有主根类型 (2个种,心叶山黑豆D. cordifolia Benth. ex Baker和柔毛山黑豆D. villosa DC.) 和无主根类型 (5个种,云南山黑豆D. yunnanensis Y. T. Wei & S. K. Lee、小鸡藤D. forrestii Diels、硬毛山黑豆D. hirsuta Craib、山黑豆D. truncata Siebold & Zucc.和长圆叶山黑豆D. henryi (Hemsl.) B. Pan & X. Y. Zhu);该属几乎全为多年生缠绕草本,只有柔毛山黑豆为半灌木,因此可能是该属中较原始的种类;该属植物的萼筒管状、筒口斜截形及花柱细长且弯曲处膨大等独特的解剖结构是区别该属其它近缘属的重要性状;花序和复叶的长度及荚果内种子数目变异幅度极大,缺乏稳定性,并非好的分类性状。 2、解剖学 应用光学显微镜,首次对山黑豆属7种植物 (心叶山黑豆、柔毛山黑豆、云南山黑豆、小鸡藤、硬毛山黑豆、山黑豆和长圆叶山黑豆) 的叶表皮进行了观察。结果表明,该属植物叶表皮细胞均呈不规则形,垂周壁为波状,气孔器类型以平列型为主。心叶山黑豆、柔毛山黑豆和云南山黑豆上表皮细胞垂周壁呈深波状;小鸡藤、长圆叶山黑豆、山黑豆和硬毛山黑豆上表皮细胞垂周壁呈浅波状。在一定程度上,上表皮细胞垂周壁的形态反映了山黑豆属种间的近缘关系。 3、细胞学 首次报道了山黑豆属3个种 (云南山黑豆、小鸡藤和硬毛山黑豆) 的染 色体数目,它们均为2n=20。在已报道染色体的植物种类中 (共计6种),仅心叶山黑豆染色体数目为2n=22,其余5种 (柔毛山黑豆、山黑豆、云南山黑豆、小鸡藤和硬毛山黑豆) 染色体数目均为2n=20。与大豆亚族大多数属染色体数目为2n=22相比较,心叶山黑豆可能是该属中较为原始的种。 4、孢粉学 在光学显微镜下,对该属7种植物 (心叶山黑豆、柔毛山黑豆、云南山黑豆、小鸡藤、硬毛山黑豆、山黑豆和长圆叶山黑豆) 的花粉进行了观察,结果表明:该属植物为三角形6孔花粉,极轴短,每个角的萌发孔由一对小孔组成;外壁具网纹,网脊粗,网眼不规则。柔毛山黑豆和小鸡藤极面的网脊几乎不断裂;心叶山黑豆、云南山黑豆、硬毛山黑豆、山黑豆和长圆叶山黑豆极面的网脊断裂较多。外壁的纹饰在一定程度上反映了该属植物的近缘关系。 5、地理分布格局 该属植物主要分布在中国南部和西南,只有柔毛山黑豆分布到非洲和大洋洲。研究结果表明,具主根的2个种 (心叶山黑豆和柔毛山黑豆) 主要分布在中国西南部,其分布区域相互重叠;而无主根的5个种 (云南山黑豆、小鸡藤、硬毛山黑豆、山黑豆和长圆叶山黑豆) 由中国西南部向东到日本、韩国都有分布,分布区域几乎不重叠。本研究认为:有主根的心叶山黑豆和柔毛山黑豆可能代表了该属的原始类群;有主根类群衍生出其余无主根类型的各种,并由中国西南扩散到其他地区。 综合以上资料,本研究对山黑豆属进行了分类修订,认为该属含8种、1亚种及2变种,其中建立新组合1个,归并6个类群,并指定了4个后选模式。另外,本研究同时提供了该属植物的检索表、种的形态描述和插图以及地理分布图等信息。
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本文通过广泛的标本室研究结合野外实地调查,对十大功劳植物进行全面的形态学性状分析研究,据此对国产十大功劳植物进行分类学修订;还开展了叶表皮形态、孢粉学和分子系统学等方面的研究,并就这些性状在十大功劳属植物中的分类价值以及属下系统发育的关系及意义进行了讨论。结果如下: 1. 形态学特征 在对国内、外18 家标本馆1500 余份标本(包括模式标本)的查阅及40 余个县针对性的野外居群考察基础上,对十大功劳属植物形态性状(包括前人使用过的)的变异式样及其分类学意义进行了分析,并对一些数量性状进行了详细的统计分析。最后确认叶柄长度、小叶形状、小叶宽度、锯齿类型、花梗与苞片的相对长度、苞片和外萼片形状、中萼片与内萼片的相对长度、花序类型、苞片形状、外萼片形状、花瓣顶端是否裂等性状在种内变异稳定,是比较可靠的分类学性状。然后,利用这些可靠的形态学性状对国产十大功劳属下种的范围进行了界定。 2. 叶表皮形态 通过对十大功劳属植物4组12个亚组53 个种及两个其它属近缘植物(Ranzania japonica and Nandina domestrica )叶表皮特征分别在光镜和电镜下进行观察,光镜下叶表皮细胞形状多为不规则形,少数为近多边形,垂周壁为波状或近平直;电镜下根据叶片下表皮的角质层突起及气孔特征将十大功劳属植物分为10 种类型,气孔都分布于下表皮。叶表皮性状对理解该属的属下系统关系有重要意义。 3. 孢粉学研究 通过对十大功劳属植物4组9个亚组18 个种植物的花粉特征的观察,发现花粉形态在属内变化比较一致,对于讨论属内组间、亚组间和种间的演化关系意义不大。 4. 种子形态 通过对十大功劳属植物4个组9个亚组的24个种及一个相关种Nandina domestica 种子形态特征研究,发现种子形态(特别是种皮纹饰)在十大功劳属内具有重要的系统学意义。根据种皮纹饰(网眼形状、网脊等)可将十大功劳属植物分为9 个类型。 5.分子系统学 在前人的工作基础上增加了15 个种,基于44 种十大功劳植物和6 种小檗属植物ITS 序列分析,显示该属可分成4 大支,基本上支持前人的4个组的划分。但就中国种类而言,尽管有几支能被明显的划分,但总体上组下关系仍不明确。另外,以M.polydonta、M.Longibracteata、M.paucijuga 为主的一支与美洲种类聚在一起,这说明这一支所代表的种类与美洲种类有较近的关系。 6. 分类处理 基于上述研究,我们对国产十大功劳属植物进行了全面的分类学修订。与《中国植物志》相比:发现新分类群2 个,新等级4 个,增加新异名3个,省级新分布1 个,并对4 个种进行了补充及订正描述。并对一些疑难类群进行了充分讨论,最后确认国产十大功劳属植物共包括38 个种,2个亚种。同时基于叶表皮、种子形态、分子序列等证据,对十大功劳属下系统进行了讨论。
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本研究在光镜和扫描电子显微镜下对裸子植物10个科、38属、53种裸子植物茎或枝的次生韧皮部解剖结构进行观察和描述。裸子植物次生韧皮部包括轴向系统(由筛胞、Strasburger细胞、韧皮薄壁组织细胞、纤维、石细胞、轴向树脂道等组成)和径向系统(由射线薄壁组织细胞、径向树脂道等组成),并具有特征性的排列样式。裸子植物各类群的次生韧皮部的组成和排列差异较大,可根据其特征进行此类植物的分类鉴定和和系统关系的探讨。本文还提出了一个根据次生韧皮部解剖结构特征的裸子植物属检索表。
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The lengths of otoliths and other skeletal structures recovered from the scats of pinnipeds, such as Steller sea lions (Eumetopias jubatus), correlate with body size and can be used to estimate the length of prey consumed. Unfortunately, otoliths are often found in too few scats or are too digested to usefully estimate prey size. Alternative diagnostic bones are frequently recovered, but few bone-size to prey-size correlations exist and bones are also reduced in size by various degrees owing to digestion. To prevent underestimates in prey sizes consumed techniques are required to account for the degree of digestion of alternative bones prior to estimating prey size. We developed a method (using defined criteria and photo-reference material) to assign the degree of digestion for key cranial structures of two prey species: walleye pollock (Theragra chalcogramma) and Atka mackerel (Pleurogrammus monopterygius). The method grades each structure into one of three condition categories; good, fair or poor. We also conducted feeding trials with captive Steller sea lions, feeding both fish species to determine the extent of erosion of each structure and to derive condition-specific digestion correction factors to reconstruct the original sizes of the structures consumed. In general, larger structures were relatively more digested than smaller ones. Mean size reduction varied between different types of structures (3.3−26.3%), but was not influenced by the size of the prey consumed. Results from the observations and experiments were combined to be able to reconstruct the size of prey consumed by sea lions and other pinnipeds. The proposed method has four steps: 1) measure the recovered structures and grade the extent of digestion by using defined criteria and photo-reference collection; 2) exclude structures graded in poor condition; 3) multiply measurements of structures in good and fair condition by their appropriate digestion correction factors to derive their original size; and 4) calculate the size of prey from allometric regressions relating corrected structure measurements to body lengths. This technique can be readily applied to piscivore dietary studies that use hard remains of fish.
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Prey-size selectivity by Steller sea lions (Eumetopias jubatus) is relevant for understanding the foraging behavior of this declining predator, but studies have been problematic because of the absence and erosion of otoliths usually used to estimate fish length. Therefore, we developed regression formulae to estimate fish length from seven diagnostic cranial structures of walleye pollock (Theragra chalcogramma) and Atka mackerel (Pleurogrammus monopterygius). For both species, all structure measurements were related with fork length of prey (r2 range: 0.78−0.99). Fork length (FL) of walleye pollock and Atka mackerel consumed by Steller sea lions was estimated by applying these regression models to cranial structures recovered from scats (feces) collected between 1998 and 2000 across the range of the Alaskan western stock of Steller sea lions. Experimentally derived digestion correction factors were applied to take into account loss of size due to digestion. Fork lengths of walleye pollock consumed by Steller sea lions ranged from 3.7 to 70.8 cm (mean=39.3 cm, SD=14.3 cm, n=666) and Atka mackerel ranged from 15.3 to 49.6 cm (mean=32.3 cm, SD=5.9 cm, n=1685). Although sample sizes were limited, a greater proportion of juvenile (≤20 cm) walleye pollock were found in samples collected during the summer (June−September) on haul-out sites (64% juveniles, n=11 scats) than on summer rookeries (9% juveniles, n=132 scats) or winter (February−March) haul-out sites (3% juveniles, n=69 scats). Annual changes in the size of Atka mackerel consumed by Steller sea lions corresponded to changes in the length distribution of Atka mackerel resulting from exceptionally strong year classes. Considerable overlap (>51%) in the size of walleye pollock and Atka mackerel taken by Steller sea lions and the sizes of these species caught by the commercial trawl fishery were demonstrated.
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Lengths of walleye pollock (Theragra chalcogramma) consumed by Steller sea lions (Eumetopias jubatus) were estimated by using allometric regressions applied to seven diagnostic cranial structures recovered from 531 scats collected in Southeast Alaska between 1994 and 1999. Only elements in good and fair condition were selected. Selected structural measurements were corrected for loss of size due to erosion by using experimentally derived condition-specific digestion correction factors. Correcting for digestion increased the estimated length of fish consumed by 23%, and the average mass of fish consumed by 88%. Mean corrected fork length (FL) of pollock consumed was 42.4 ±11.6 cm (range=10.0−78.1 cm, n=909). Adult pollock (FL>45.0 cm) occurred more frequently in scats collected from rookeries along the open ocean coastline of Southeast Alaska during June and July (74% adults, mean FL=48.4 cm) than they did in scats from haul-outs located in inside waters between October and May (51% adults, mean FL=38.4 cm). Overall, the contribution of juvenile pollock (≤20 cm) to the sea lion diet was insignificant; whereas adults contributed 44% to the diet by number and 74% by mass. On average, larger pollock were eaten in summer at rookeries throughout Southeast Alaska than at rookeries in the Gulf of Alaska and the Bering Sea. Overall it appears that Steller sea lions are capable of consuming a wide size range of pollock, and the bulk of fish fall between 20 and 60 cm. The use of cranial hard parts other than otoliths and the application of digestion correction factors are fundamental to correctly estimating the sizes of prey consumed by sea lions and determining the extent that these sizes overlap with the sizes of pollock caught by commercial fisheries.
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忍冬(Lonicera japonica Thunb.)属忍冬科忍冬属,是一种重要的药用植物,其花蕾称为金银花(Flos Lonicerae),在我国已有1000多年的药用历史,具有清热解毒、凉散风热等功效。我们利用秋水仙素诱导二倍体“大毛花”品种茎尖选育出同源四倍体“九丰一号”品种,并在生产中发现花蕾产量显著提高,而药效成份含量是否发生变化了呢?四倍体忍冬表现出典型的器官巨大性,这些变化是否与其较强生态适应性之间存在联系呢?染色体加倍增强了忍冬的生态适应性,其生态修复功能如何呢?在本研究中,主要从以下几个方面进行了探讨:(1)染色体加倍对其叶片,茎、花蕾和花蕾产量及其药效成份等生物学性状的影响;(2)染色体加倍后植物对水分胁迫的响应;(3)染色体加倍后植物对热胁迫的响应;(4)除上述两个品种外,增加一个变异品种“红银花”,探讨3个忍冬品种对退化生态系统的修复功能。主要结果如下: 1. 通过测定根尖细胞染色体数目和使用流式细胞仪分析茎尖细胞DNA含量,表明四倍体忍冬(2n = 4x = 36)确实来自二倍体忍冬(2n = 2x = 18)的染色体加倍。四倍体忍冬气孔细胞大小显著大于二倍体,而气孔密度显著低于二倍体。四倍体忍冬没有光合“午休”,而二倍体存在明显的光合“午休”,这可能与其存在抗高温的叶片解剖结构特性有关。四倍体忍冬叶片较二倍体变大、变厚、变浓绿(较高叶绿素含量)。与二倍体相比,四倍体忍冬单位叶面积重量显著增高,表明其具有较强的生态适应性。四倍体忍冬单个花蕾的鲜重和干重均显著大于二倍体。连续3年的花蕾产量调查表明,四倍体显著高于二倍体。染色体加倍使其茎干粗壮、节间变短、新梢上着生花蕾数目增多及单个花蕾变大,这是其花蕾高产的生物学基础。对金银花的药效成份而言,染色体加倍不影响绿原酸的含量,但增加了木犀草苷的含量。结果表明,染色体加倍能增加金银花的产量和药效成份的含量,建议四倍体忍冬在药材生产中推广应用。 2. 水分胁迫显著降低二倍体和四倍体忍冬叶片的净光合速率、气孔导度和蒸腾速率。水分胁迫也降低电子传递速率、光系统II实际量子产量和光化学猝灭,而增加非光化学猝灭、总可溶性糖、脯氨酸和丙二醛的含量。四倍体忍冬对水分胁迫的响应表现为其叶片水势、气体交换、叶绿素荧光和有关代谢物含量的变化程度低于二倍体,并且复水后其恢复能力快于二倍体,表明染色体加倍增强了忍冬的抗旱能力。分析其主要原因,可能是由于四倍体植株总叶面积减少、单位叶面积重量增加、叶片表皮细胞和栅栏组织增大以及叶片表皮毛较浓密等形态解剖结构特性有关。结果表明,染色体加倍能增加忍冬植物的抗旱能力,而使其具有较强的生态适应性。 3. 二倍体和四倍体忍冬受48 ºC热胁迫处理6 h和恢复10 h,以及离体叶片45 ºC,50 ºC,55 ºC 水浴热胁迫3 min,应用叶绿素荧光成像系统研究了它们对热胁迫的响应。热胁迫显著降低了两个品种叶片的最大光化学效率、电子传递速率、光系统II实际量子产量和光化学猝灭,降低了四倍体的非光化学猝灭,而增加了二倍体的非光化学猝灭。热胁迫增加了两个品种叶片的总可溶性糖、脯氨酸和丙二醛的含量。四倍体受热胁迫的叶绿素荧光参数和有关代谢物的响应程度低于二倍体,以及其恢复程度快于二倍体,表明染色体加倍提高了抗热性。此外,叶绿素荧光成像的异质性也表明,四倍体的抗热能力大于二倍体。进一步的叶片解剖结构分析表明,四倍体叶片的表皮细胞变大、栅栏组织增厚、表皮毛较浓密等特点,是其抗热性强的主要原因。 4.根据以上的研究结果,通过四倍体忍冬生态修复功能的野外试验证明染色体加倍后其生态适应性变化。在本研究中,针对北京市门头沟区大面积不同类型的废弃地急需恢复植被和景观的问题,在恢复生态学理念的指导下,综合运用集成技术,将3个忍冬品种植物用于这些退化生态系统的恢复。在王平镇的公路下边坡(以碎石和矿渣为主)、煤矿、石灰窑和采石场4种类型废弃地建立生态修复的试验示范区。结果表明,在4个废弃地类型上引进的3个金银花品种,具有使示范区快速复绿、当年成景和群落快速形成的潜力,并具有对不同退化迹地的适应能力和恢复效果,其中四倍体忍冬效果更好些,这主要与其形态解剖结构和较强的生态适应性有关。
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Morphology and taxonomy of four species of Ulva i.e. U. anandii Amjad et Shameel sp. nov., U. bifrons Ardre, U. saifullahii Amjad et Shameel sp. nov. and U. taeniata (Setchell) et Gardner were described for the first time from Pakistan. Their anatomy has been investigated in detail and compared with the allied species. A taxonomic comment has been written on U. grandis Saifullah et Nizamuddin.
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Hilsa (Hilsa ilisha) caught by gill net were immediately killed by cranial spiking. Three fish were kept in ice (0°C) and three other at room temperature (33°C) to follow development of rigor mortis and changes in muscle pH. The rest were frozen stored at -20°C. Rigor started 15 minutes after death in all fish and reached full rigor (100%) state in 2 and 4 hours respectively in fish kept at 33° and 0°C. The fish at 33°C deteriorated 16 hours after while in full rigor but those at 0°C lasted 26 hours of death without deterioration. Freshly caught hilsa had a muscle pH around 7 which decreased with time rapidly at 33°C and slowly at 0°C. The relative proportion of protein fraction in white and dark muscle of fish stored at 0°C and -20°C were also studied. The proportion of dark muscle was 30.34% of the white muscle. White muscle in fish at 0°C was found to contain 32.0% sarcoplasmic, 57.6% myofibrilla, 9.4% alkali-soluble and 1.1% stroma protein whereas these proteins in dark muscle were 29.9%, 58.4%, 9.8% and 1.9% respectively. The protein fractions of white muscle in frozen-fish were found 27.6% sarcoplasmic, 64.7% myofibrilla, 6.0% alkali-soluble and 1.7% of stroma protein whereas they were 30.6%, 58.6%, 8.9 and 1.9% for dark muscle. Some changes occurred in protein composition during frozen storage. The relative amounts of sarcoplasmic, alkali soluble and stroma protein fractions decreased while myofibrilla fraction increased in frozen condition. This may be attributed to drip loss of soluble protein during thawing.
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The quality and shelf-life of three freshwater fish species of Bangladesh, catla (Catla catla), magur (Clarias batrachus) and tilapia (Oreochromis niloticus) stored at room temperature and ice were evaluated. Live fishes were killed by cranial spiking and stored at room temperature (27-30 °C), ice stored immediately after death, 5 hr after death and 10 hr after death. The shelf-life and quality of the fishes were evaluated by organoleptic method, rigor-mortis studies and bacteriological assessment. Fishes kept at room temperature became organoleptically unacceptable within 16-20 hr duration. Ice stored fishes showed considerable differences in their shelf-life when icing was delayed for different duration. Shelf-life of catla ice stored immediately after death was 20 days but shelf-life reduced to 12 days when icing delayed for 10 hr after death. Similar trend was observed for two other fish species magur and tilapia. Rigor-index of the fishes stored under different conditions also considerably varied among the three fish species, particularly effect of delayed icing was very much evident. Bacteriological study showed patterns of Aerobic Plate Count (APC) at the end of shelflife study when fishes became organoleptically unacceptable were more or less similar for all the three fish species stored under different conditions. No definite pattern was observed in the generic distribution of bacteria in different fish species under different storage conditions. Micrococcus, Coryneforms, Pseudomonas and Achromobacter were the dominant groups of bacteria isolated from the fishes spoiled at room temperature and ice stored condition.
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With modified DNA extraction and Purification protocols, the complete cytochrome b gene sequences (1140 bp) were determined from degraded museum specimens. Molecular analysis and morphological examination of cranial characteristics of the giant flying squirrels of Petaurista philippensis complex (P. grandis, P. hainana, and P. yunanensis) and other Petaurista species yielded new insights into long-standing controversies in the Petaurista systematics. Patterns of genetic variations and morphological differences observed in this study indicate that P. hainana, P. albiventer, and P. yunanensis can be recognized as distinct species, and P. grandis and P. petaurista are conspecific populations. Phylogenetic relationships reconstructed by using parsimony, likelihood, and Bayesian methods reveal that, with P. leucogenys as the basal branch, all Petaurista groups formed two distinct clades. Petaurista philippensis, P. hainana, P. yunanensis, and P. albiventer are clustered in the same clade, while P. grandis shows a close relationship to P. petaurista. Deduced divergence times based on Bayesian analysis and the transversional substitution at the third codon suggest that the retreating of glaciers and upheavals or movements of tectonic plates in the Pliocene-Pleistocene were the major factors responsible for the present geographical distributions of Petaurista groups. (c) 2005 Elsevier Inc. All rights reserved.
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This report gives information on the anatomy of the internal genital organs of male and female Penaeus monodon.