水稻幼苗特性与籽粒大小关系的分子检测

水稻( Oryza sativa L.)幼苗特性如叶的发生、叶绿素含量、植株高度等对早期生长是重要的,与籽粒大小相联系.以水稻珍汕97A和明恢63组合的重组自交系群体为材料,对5个幼苗特性性状和籽粒大小进行了数量性状基因定位(QTL),目的在于从遗传水平探求幼苗特性与籽粒大小的内在关系.对叶绿素a、总叶绿素含量、第二片叶长、第三片叶长、幼苗高度、粒重分别检测到2、1、5、4、4、9个QTLs.结果揭示4个幼苗特性性状的QTL和4个籽粒大小的QTL位点分别定位在4个相似区域 (G359-RG532、C567-RG236、RZ403-R19和C371-C405a),表明幼苗特性性状与籽粒大小间的紧密关系,也显示控制籽粒大小的几个染色体区域对幼苗特性性状没有影响,这意味着通过标记辅助选择改良幼苗活力但并不增加粒重是可能的.     

水稻株形对纹枯病抗性的影响

利用240份源于珍汕97B／明恢63的重组自交系水稻(Oryza sativa L.)群体,连续2年调查纹枯病病级与水稻生育期、株高和叶片长宽等18个株形性状的关系。对株形性状与纹枯病病级进行了偏相关分析。实验结果,只有植株松紧度与病级表型偏相关两年中都达到了显著或极显著水平,倒2叶基角、穗层整齐度等8个性状与病级之间的偏相关只有一年达显著或极显著水平。结合构建的分子标记遗传连锁图谱,对各性状进行QTL定位。在抗纹枯病QTL相近区间仅检测到控制分蘖角、植株松紧度和倒2叶基角的QTLs,未发现其余株形性状QTLs与抗纹枯病QTLs分布在同一染色体上。结果表明,水稻对纹枯病的抗性主要是由本身抗性基因控制,株形对纹枯病抗性表达的影响主要是间接影响,即通过改变田间小气候而影响发病程度。抗纹枯病育种在累加主效抗纹枯病QTLs的同时,也要注重选择不利于纹枯病发展的株形性状。     

白条草蜥消化道内分泌细胞的免疫组织化学

应用6种胃肠激素抗血清和免疫组织化学ABC法(avidin-biotin complex method),对白条草蜥(Takydromus wolteri)消化道内分泌细胞进行了免疫组织化学定位研究和形态学观察。结果表明,5-羟色胺细胞较其他5种内分泌细胞的分布更为广泛,整个消化道中(即从食管到直肠)均有分布,其分布密度高峰位于幽门。食管、回肠和直肠未检测到生长抑素细胞,生长抑素细胞在幽门部分布密度最高,总体来说生长抑素细胞的分布在胃部较高而在小肠部较低。胃泌素细胞和胰多肽细胞分布在小肠,均在十二指肠分布密度最高。胰高血糖素细胞在胃幽门部分布密度最高,十二指肠、空肠次之,回肠分布密度最低。P-物质细胞仅分布于幽门部。6种内分泌细胞以圆形和锥体形为主,它们广泛分布于消化道黏膜之间、腺泡上皮细胞之间及上皮细胞基部。内分泌细胞的密度分布与其食性、食物组成和生活环境有关,它们的形态与其内、外分泌功能是相适应的。     

关于窄膜棘豆(Oxytropis moellendorffii Bunge)(豆科)的分类学研究

作者对窄膜棘豆(Oxytropis moellendorffii Bunge)的分类学处理提出了新的观点:通过对原产地标本、资料的研究,认为五台山棘豆(O. wutaiensis Tatewakiet Hurusawa)实际上是窄膜棘豆(O. moellendorffii Bunge),对其变种(O. wutaiensis Tatew akiet Hurusaw a var. glabrata Tatewaki et Hurusawa)也进行了归并;另外本文中发表一个新等级--西灵山棘豆(O. moellendorffii Bunge var. sylinchanensis(Franch.)G.Z.Qian)。     

低温处理下不同禾本科牧草的生理变化及其抗寒性比较

研究牧草根系抗寒性的动态变化,对寒冷地区的牧草引种筛选意义重大.试验以美国引进的禾本科牧草高山早熟禾(Poa Aalpine)、俄罗斯野麦(Elymus junceus)、无芒冰草(Agropyron inerme)、爱达荷冰草(Agropyron inerme)(品种名Secar)和爱达荷冰草(Agropyron inerme)(品种名Goldar)为研究材料,人工控温进行低温抗寒锻炼、冷冻处理和解冻恢复生长,测定每一阶段下根系中MDA、可溶性蛋白质、可溶性糖和脯氨酸的含量及SOD活性.结果表明,MDA含量在抗寒锻炼后略有增加,随后维持基本稳定;SOD活性在抗寒锻炼后升高,冷冻处理后显著降低;返青后又显著升高(P＜0.05);可溶性蛋白质、可溶性糖和脯氨酸含量在抗寒锻炼和冷冻处理后升高,返青后降低;其中,SOD活性、可溶性糖和脯氨酸的含量随处理不同变幅较大,MDA和可溶性蛋白质的含量随处理不同变幅较小.运用Fuzzy数学中隶属函数法进行抗寒性综合评判,得出抗寒性强弱顺序为:高山早熟禾＞俄罗斯野麦＞爱达荷冰草(Secar)＞无芒冰草＞爱达荷冰草(Goldar).     

Multi-gene phylogenetic analyses reveals <Emphasis Type="Italic">Neohelicosporium</Emphasis> gen. nov. and five new species of helicosporous hyphomycetes from aquatic habitats

Helicosporous hyphomycetes are a morphologically allied group of Tubeufiales. We introduce a new helicosporous genus, Neohelicosporium, with five new species, Neohelicosporium aquaticum, N. guangxiense, N. hyalosporum, N. parvisporum, and N. thailandicum, based on morphological and phylogenetic evidence. The RPB2 protein gene data are provided to analyze their phylogeny in Tubeufiales. Phylogenetic analyses of combined ITS, LSU, RPB2, and TEF1α sequence data from 13 new isolates of Neohelicosporium provided evidence to support the establishment of the new taxa. The morphological characters of Neohelicosporium that differentiate it from other helicosporous species are compared and discussed.     

Characteristics of soil nematode community along an age sequence of sandy desert soil cultivation in a marginal oasis of middle reaches of Heihe River

This paper studied the characteristics of soil nematode community following the conversion of native sandy desert soil to irrigated farmland in a marginal oasis of the middle reaches of Heihe River basin, aimed to approach the bioindicating function of soil nematodes in soil evolution process. A total of 27921 soil nematode individuals were captured, belonging to 25 families and 34 genera. The total number of nematodes increased gradually with increasing age of cultivation. At all sampling sites, bacterivores and plant parasites were the dominant trophic groups, and made up the main parts of nematode community in oasis farmland. Through the analysis of the evenness index (J) and dominance index (lambda) of nematode community, the ecosystems were found to be fragile for the farmlands having cultivated for 0, 10, and > 50 years. The maturity index MI2-5 and MMI decreased with increasing cultivation age, suggesting that the practice of agricultural use enhanced the disturbance on farmland. The soil properties changed significantly after 10 years of cultivation, which was at a significant change stage for the structure stability of soil ecosystems. The characteristics of soil nematode community could be used as the bioindicator of soil evolution following the conversion of native desert soil to irrigated farmland.     

青岛文昌鱼精子运动特征及计算机辅助分析

青岛文昌鱼的精子在精浆中不运动,在与精浆等渗的生理溶液中也不运动,把精液稀释到过滤海水或人工海水后,精子运动被激活。文昌鱼新鲜精液中精子浓度为(9.4±1.6)×1010/ml;在人工海水中,运动精子占总精子数的85.8%±6.9%,精子运动持续的平均时间是22.7±2.6min。文昌鱼精子经人工海水激活0.5min后,可观察到四种运动方式:(1)向前直线运动,其平均速度93.6±23.7μm/s,这类精子所占的百分比为27.8%±3.1%;(2)弧形曲线运动,平均速度55.6±18.9μm/s,所占的百分比为44.3%±2.5%;(3)左右摆动,平均前进速度27.4±13.4μm/s,所占百分比为14.7%±1.8%;(4)运动速度小于5μm/s的精子,视为不运动的精子,所占百分比为13.2%±1.8%。随着激活时间的延长,文昌鱼精子的运动状态发生改变,向前直线运动和弧形曲线运动的精子逐渐减少,而左右摆动和不运动的精子逐渐增多。