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1.
Marrow-stem kale plants grown on plots receiving frequent additions of sulphate of ammonia showed a 40% increase in length of internode and a 25% increase in number of nodes per plant, and the leaf size was increased by between 50 and 70% over plants in plots receiving no N fertilizer. Leaves of kale continue to increase in area until they turn yellow, and the high N leaves showed a greater rate of increase in area at every stage in the life of the leaf.
Various features of leaf structure, such as stomatal index, and thickness of palisade and mesophyll, were unaffected by N treatment. The size of the epidermal cells of the leaves was very variable, and although the high N leaves showed a 12% increase in area per epidermal cell over the low N leaves, this difference is not statistically significant. The increased area of the high N leaves can therefore be attributed mainly to increased cell division during the life of the leaf. Only a very slight increase in rate of cell division is necessary to produce the observed effect.
The greater leaf area of the high N plants can be attributed mainly to increased size of individual leaves, but there was also a significantly greater number of living functional leaves per plant on the high N plants; at 23 weeks from sowing the high N plants had an average of 13.4 living leaves, while the low N plants had only 11.7 living leaves per plant.
There was an appreciable degree of N succulence in the high N kale leaves, which showed a 2% greater moisture content than the low N leaves.
A seasonal drift in epidermal cell size, palisade thickness, and total leaf thickness, is shown to be fully significant, statistically. Marked variations in stomatal frequency are barely significant at the 5% level.  相似文献   

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饲料营养对林麝麝香产量和品质的影响   总被引:17,自引:0,他引:17  
上海地区引种林麝取得成功后,首次进行了饲料营养对麝香产量和品质影响的研究,试验麝饲养在上海市郊崇明岛东平林场,进行分期对比试验,分别用青绿饲料,青绿饲料加代蛋白饲料,青绿饲料加高蛋白饲料,配合饲料饲喂受试麝,考察饲料营养对麝香产量和质量的影响。结果表明,饲料营养显著影响麝香产量和品质,单独饲青绿饲料不能满足泌香的营养需要,平均产香量3.21g,麝香色深而湿,品质差,提高营养水平后,麝香产量显著提高  相似文献   

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The domestic dog varies remarkably in cranial morphology. In fact, the differences in size and proportion between some dog breeds are as great as those between many genera of wild canids. In this study, I compare patterns of intracranial allometry and morphologic diversity between the domestic dog and wild canid species. The results demonstrate that the domestic dog is morphologically distinct from all other canids except its close relatives, the wolf-like canids. Following this, I compare patterns of static and ontogenetic scaling. Data on growth of domestic dogs are presented and used to investigate the developmental mechanisms underlying breed evolution. Apparently, most small breeds are paedomorphic with respect to certain morphologic characters. In dogs and other domestic animals, morphologic diversity among adults seems to depend on that expressed during development.  相似文献   

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The intertidal seaweeds Corallina vancouveriensis Yendo and Gelidium coulteri Harv. respond to the experimental removal of associated mats of the clonal anemone Anthopleura elegantissima Brandt with morphological changes that affect their photosynthetic performances. With the removal of anemones, these seaweeds develop a tight compaction of thalli which aids in the retention of moisture during aerial exposure. The morphological response, however, results in greatly reduced net photosynthesis in C. vancouveriensis (–98%) and G. coulteri (–73%) on an areal basis. Association with the clonal anemones allows these seaweeds to maintain a morphology that is more highly productive yet inconsistent with the exposure stresses in many microhabitats at similar tidal levels.  相似文献   

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Eleven strains of Pandorina unicocca sp. nov. were studied for morphological characterization. The species was delimited by having cells which contain a single basal pyrenoid and by colonies which have cells separate from each other in the colonial envelope. A defined medium was developed for 4 strains of P. unicocca and the nutritional requirements of these strains were examined. All 4 strains were capable of completely autotrophic growth and they could utilize nitrate, ammonium, or urea as nitrogen sources. Optimum growth was nuts attained at pH 8.0.  相似文献   

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岩梧桐属的花粉形态及其分类学意义   总被引:2,自引:2,他引:0  
本文通过光学显微镜和扫描电镜对岩梧桐属Wightia Wall.花粉进行了深入的观察,并与紫葳科和玄参科部分属种作了详尽的比较。结果认为,从花粉的大小等级、萌发孔特征、外壁内外层比例等看,岩梧桐属花粉与玄参科的花粉更类似,而与紫葳科的相距较大。孢粉学支持把岩梧桐属置于玄参科。该属的国产种,根据花粉的大小和外壁纹饰特征的差异划分为两个种较为合理和自然,不该合并为一个种。  相似文献   

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西鄂尔多斯六种强旱生植物的花粉形态及其生态因子   总被引:2,自引:0,他引:2  
为了探讨特殊生境条件下强旱生植物的花粉形态与生态因子的相关性,应用光学显微镜对西鄂尔多斯地区5月份开花的2科5属6种强旱生灌木刺柄叶棘豆(Oxytropis aciphylla Ledeb)、沙冬青[Ammopiptanthus mon-golic (Maxim) Cheng f.]、狭叶锦鸡儿(Caragana stenophylla Pojark)、四合木(Tetraena mongolica Maxim),霸王(Zygophyllum xanthoxylon Maxim)和柠条锦鸡儿(Caragana korshinskii Kom)的花粉形态进行了观察和研究.结果表明:花粉粒近球形至长球形,萌发孔主要是3孔沟,沟狭.外壁纹饰主要是细网状纹饰.同时研究了采样点生态因子,包括地理位置、海拔高度、年降水量、年积温及生境等,特别提供了5月份的气候因子,得出这些花粉分布区的主要生态因子.  相似文献   

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珍珠菜属植物的花粉形态及其系统进化学意义   总被引:7,自引:0,他引:7  
利用光学显微镜、扫描电镜和透射电镜对20 种珍珠菜属植物的花粉形态结构进行了详细研究。根据花粉的大小、形状、表面纹饰和外壁构造等特征可划分为四大类型,即细梗香草型、白花过路黄型、过路黄型和黑腺珍珠菜型。对它们可能的进化水平进行了分析,并结合形态学、细胞学等资料进一步探讨了珍珠菜属各亚属间的系统演化关系。  相似文献   

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Abstract:  The exceptionally preserved hyolithids Gompholites striatulus , Maxilites robustus , Maxilites snajdri and Maxilites sp. are described with particular emphasis on helen and muscle scar morphology. These two aspects of hyolithid morphology have remained controversial. In life position, each helen curved ventrally. When the operculum closed the aperture of the conch, each helen was locked at the commissure slit with its dorsal edge tilted forward. Inside the conch, it was held in the dorsal apertural plane and clear of the inner surface of the operculum. Previously unidentified muscle scars are described from both the operculum and the conch. Dorsal scars on the conch aperture held muscles directed to the operculum. Comparative study of the muscle insertion pattern indicates that hyolithids did not have serially arranged muscles and that all hyolithids may have had a common skeleto-muscular system. The arrangement of the muscle scars with respect to the helens suggests that the latter were capable of relatively complex movements and could have been used to propel the organism over the substrate. The general morphology and orientation of the helens suggests that in addition they functioned to stabilize the organism on the sea-floor.  相似文献   

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栝楼属花粉形态研究及其在分类学上的意义   总被引:5,自引:0,他引:5  
本文收集了国内外栝楼属Trichosanthes 31种1变种,在光学显微镜和扫描电镜下,进行了花粉粒形态的比较观察。该属花粉粒为3孔沟型,外壁表面纹饰可分为四个类型,即:疣状或皱波状(小苞组),粗网状(大苞组),细网状或光滑(叶苞组),近光滑或皱波状(王瓜组)。这四个类型的划分与植物形态分类基本一致,可作为分组及分种的依据之一。花粉特征支持将叶苞组分为叶苞亚组和柔毛亚组,如叶苞亚组有明显的沟,而柔毛亚组没有。  相似文献   

15.
布雷费尔德(O. Brefeld)虽对真菌纯培养方法的改进和真菌发育与生理知识作出了不少贡献,但他的主要贡献还是对真菌系统发育的观点。按照他的这种观点,卵菌不是真正的真菌,它应与粘菌一起排除在真菌之外,而真正的真菌应从接合菌开始。他并将子囊菌和担子菌分别分为半子囊菌和真子囊菌,半担子菌和真担子菌。  相似文献   

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布雷费尔德(O. Brefeld)虽对真菌纯培养方法的改进和真菌发育与生理知识作出了不少贡献,但他的主要贡献还是对真菌系统发育的观点。按照他的这种观点,卵菌不是真正的真菌,它应与粘菌一起排除在真菌之外,而真正的真菌应从接合菌开始。他并将子囊菌和担子菌分别分为半子囊菌和真子囊菌,半担子菌和真担子菌。  相似文献   

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人工鱼礁建设对浙江嵊泗海域营养盐与水质的影响   总被引:6,自引:0,他引:6  
根据2003-2007年对嵊泗人工鱼礁海域11个航次调查所获得的实验数据,运用鱼礁区和对照区相比较的方法,分析了该海域不同季节氮、磷营养盐和水质在投放人工鱼礁后的变化,并对海域水质状况进行评价。结果表明,无机氮大多数处于阈值范围或低于最小阈值,活性磷酸盐含量则严重超标,N/P值范围为0.6280-14.8273,嵊泗海域处于氮限制,溶解氧不成为该海域浮游生物的生长限制因子。投放人工鱼礁后,生态效应不能在短期里得以体现,鱼礁区的水质情况要好于对照区,海域对P的富集强度大于N,人工鱼礁建设对再生生产力影响较大,对新生产力的贡献很小。    相似文献   

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壳聚糖是一种广泛应用的生物可降解材料,该论文研究了几种与壳聚糖相关的材料对骨髓基质细胞生长和分化的作用,主要实验方法是在材料表面培养骨髓基质细胞并对其进行诱导促使其向成骨细胞方向分化。通过对细胞生长和分化情况的观察和测定,对几种材料与骨髓基质细胞的亲和性作出了评价。另外,通过ELISA法测定了细胞外基质分子在材料上的吸附量,测量了各材料的表面接触角以研究细胞在材料表面的铺展和增殖。结果表明尽管壳聚糖本身与骨髓基质细胞并不具有很好的亲和性,但通过与明胶混合,壳聚糖的生物相容性得到了明显提高,是很有应用前景的骨修复材料。  相似文献   

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以硝酸盐利用缺陷型突变(nit突变)和抗杀菌剂突变两种遗传标记,对大丽轮枝菌(Verticilliumdahliae)异核体后代的形态和致病力进行研究,结果表明,菌核型菌株与菌丝型菌株经菌丝融合形成异核体后,菌丝型菌株能恢复形成微菌核,其后代单孢菌落形成微菌核的数量明显低于菌核型亲本,且遗传性状不稳定;随着转代次数的增多,微菌核形成能力的丧失较菌核型亲本菌株快。异核体后代对棉苗的致病力变化较大,一般均低于致病力强的亲本菌株,或介于两个亲本致病力之间,或与亲本致病力相近。  相似文献   

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以硝酸盐利用缺陷型突变(nit突变)和抗杀菌剂突变两种遗传标记,对大丽轮枝菌(Verticilliumdahliae)异核体后代的形态和致病力进行研究,结果表明,菌核型菌株与菌丝型菌株经菌丝融合形成异核体后,菌丝型菌株能恢复形成微菌核,其后代单孢菌落形成微菌核的数量明显低于菌核型亲本,且遗传性状不稳定;随着转代次数的增多,微菌核形成能力的丧失较菌核型亲本菌株快。异核体后代对棉苗的致病力变化较大,一般均低于致病力强的亲本菌株,或介于两个亲本致病力之间,或与亲本致病力相近。  相似文献   

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