不同时期施钾对甘薯光合产物运转动力的调控

【目的】通过甘薯不同时期施用钾肥的大田试验,探讨不同时期施用钾肥对甘薯光合产物运转动力的调控效应。【方法】选用典型的食用型甘薯品种"北京553",以硫酸钾(K2SO4)为供试肥料,于2011 2012年2个生长季在山东农业大学农学试验站进行大田试验。试验处理为:不施用钾肥(CK)、全部钾肥基施(JS)、全部钾肥封垄期追施(FS)和全部钾肥高峰期追施(GS)。分析不同时期施用钾肥对功能叶光合产物的输出能力、运输茎的农艺特性、源-库间光合产物运输的渗透动力(茎顶-基部间碳水化合物、氨基酸和K+浓度梯度)及块根中光合产物积累特性的影响。【结果】施用钾肥可显著提高块根鲜薯产量和干重,提高块根膨大速率,其中,基施和封垄期追施钾肥处理增幅较大。基施钾肥显著降低生长前期(栽秧后50 d左右)功能叶碳水化合物含量和蔗糖/淀粉比值,提高生长中后期(栽秧后110 d、170 d左右)功能叶中蔗糖和蔗糖/淀粉比值,增幅分别为10.01%和27.14%(2011),16.16%和61.57%(2012),提高该时期功能叶蔗糖的输出能力。基施还提高生长前期基部茎粗,两年增幅均在20%以上,增大光合产物运输的横截面积;基施和封垄期追施钾肥处理提高生长中后期分枝数,基施处理两年增幅的均值为36.53%和48.44%,封垄期追施的为19.60%和46.17%;同时,降低生长中后期源-库距离,提高有效距离(51—200 cm)所占比例。茎顶部到基部间氨基酸和K+浓度逐渐降低,施用钾肥能提高该浓度梯度的降幅,提高渗透动力,以基施和封垄期追施效果较好,其中,氨基酸浓度两处理的平均增幅分别为87.58%和39.56%,K+浓度的平均增幅分别为272.81%和75.58%。基施钾肥显著降低生长前中期茎基部蔗糖和淀粉含量,基施和封垄期追施钾肥可显著降低生长后期茎顶部和基部蔗糖含量,同时降低淀粉含量。【结论】施用钾肥可减少生长前期功能叶中淀粉的合成,保证块根中光合产物的充足供应,扩大运输通道的横截面积,提高茎部运输的渗透动力促进茎基部光合产物的卸载,及时形成较强的库,提高生长中后期功能叶蔗糖含量和可运输态(蔗糖)的比例,增加光合产物运输通道数量,降低运输距离,提高运输有效性,并提高茎部运输的渗透动力,促进茎基部光合产物卸载,促进块根的膨大,形成高产。在本试验条件下,基施钾肥处理最优。     

切沟对沟岸地土壤水分的影响

In order to preliminarily look at rules for soil moisture changes in the bank of the gully and to provide some recommendations for vegetative restoration in gully bank regions in the Loess Plateau, changes of soil moisture with depth and distance to the gully edge and their dynamic changes with time were observed to study the soil water characteristics in the bank of the gully. The results showed that soil water content increased with increasing distance from the gully edge, whereas for the same time period, the closer the distance to the gully wall, the greater the water loss; and that the influential distance of side evaporation decreased as depth increased.     

模板法自动提取遥感图像耕地变化信息的研究

该文在多时相遥感图像中采用主成份差异法提取耕地变化信息，研究的关键在于差值前如何进行图像匹配、如何自动提取变化信息以及差值后如何确定变化阈值。在逐像元判断是否变化时，根据计算机视觉的数据处理思想提出一种采用(2n+1)×(2n+1)判断模板进行判断的方法，这种方法可以大幅度地改善单像元判断的效果。经试验，提取耕地变化信息的准确程度达85％以上，可以替代人工判读的工作。     

Database derived microsatellite markers (SSRs) for cultivar differentiation in <Emphasis Type="Italic">Brassica oleracea</Emphasis>

Fifty-nine Brassica oleracea cultivars, belonging to five botanical varieties, were evaluated for microsatellite (SSR) polymorphisms using 11 database sequence derived primer pairs. The cultivars represented 12 broccoli (Brassica oleracea var. italica), ten Brussels sprouts (B. o. var. gemmifera), 21 cabbage (B. o. var. capitata, including the groups white and red cabbage), six savoy cabbage (B. o. var. sabauda), and ten cauliflower (B. o. var. botrytis) cultivars from 13 seed suppliers. The 11 primer pairs amplified in total 47 fragments, and differentiated 51 of the cultivars, whereas the remaining eight cultivars were differentiated from the rest in four inseparable pairs. All SSR markers, except one, produced a polymorphic information content (PIC value) of 0.5 or above. The average diversity for all markers within the tested material was 0.64. There was no major difference in the diversity within botanical varieties and groups. The cluster analysis and the resulting dendrogram showed that the cultivars tended to group within these taxonomic units. The present study substantiates the use of microsatellite markers as a powerful tool for cultivar differentiation and identification in vegetable brassicas.     

鹅掌楸属树种繁殖性能的遗传分析

分析影响鹅掌楸繁殖性能的遗传效应。以鹅掌楸、北美鹅掌楸各4株成年个体作为交配亲本,进行8×8全双列交配设计,以各交配组合子代的出苗率来评价各亲本的雌、雄繁殖性能,分析影响鹅掌楸繁殖性能的父本效应、母本效应、父母本交互作用效应、各亲本的一般配合力及各交配组合的特殊配合力。同时,利用11个SSR位点信息估算亲本间遗传距离,分析亲本间遗传距离与繁殖性能之间的相关性。结果表明:鹅掌楸繁殖性能主要受母本效应影响,父本效应可以忽略;繁殖性能的一般配合力亲本间差异较大,且雌性大于雄性;种内交配的特殊配合力远高于种间杂交。尽管亲本遗传距离与杂交亲和性二者间相关不显著,但仍存在如下趋势:种内杂交的亲和性随遗传距离增大而增加;而种间杂交的亲和性则随遗传距离增大而降低。研究结果对于鹅掌楸杂交种子园的亲本选配及杂种优势利用有重要的参考意义。     

短距离样点对土壤呼吸空间变异预测精度的影响

不同采样设计会对土壤呼吸空间变异特征的预测精度产生重要影响。本研究选取黄淮海平原北部潮土区1 km×1 km夏玉米样地,在7×7单元规则格网(样点间距167 m)、完全随机(样点平均间距433 m)以及3×3单元规则格网+完全随机(样点平均间距405m)3种布点方式的基础上,保持样本总量(49)不变,以占总样点2%～14%的短距离样点(样点间距4m)随机替换原方案相应样点个数的方法优化布点方式,应用普通克里金法插值,以均方根误差(RMSE)和确定系数(R2)作为验证指标,检验基于3种布点方式设置的短距离样点对土壤呼吸空间变异预测精度的影响。结果表明:研究区土壤呼吸平均速率为2.65μmol·m?2·s?1,空间分布均呈西高东低,表现出中等程度变异。采样设计对土壤呼吸空间分布的预测精度影响显著,基于3种布点方式设置短距离样点可提高预测精度7%～13%。无短距离样点替换时,规则格网+完全随机的布点方式最优,比完全随机布点和规则格网布点的空间插值预测精度分别提高10%和22%;设置短距离样点替换后,在最优布点方式(规则格网+完全随机)中,对土壤呼吸空间变异的预测精度可再提高4%～7%,其中短距离样点个数占样本总量10%对土壤呼吸空间变异预测精度的提高最为明显。研究发现,基于相同的样本数量设置短距离样点可增加区域范围内样点密度,提高土壤呼吸空间变异预测精度及试验结果的可靠性。因此,在黄淮海平原北部潮土区100 hm2尺度的夏玉米样地中,规则格网+完全随机+10%短距离样点的布点方式是预测土壤呼吸空间变异最适宜的采样布点方式。     

泰国产方斑东风螺养殖群体遗传多样性的RAPD分析

用随机扩增多态性DNA(RAPD)技术对泰国产方斑东风螺养殖群体的遗传多样性进行检测,从100个随机引物中筛选出21个引物对方斑东风螺的DNA进行扩增,结果表明:21个引物共检测到222条清晰且重复性好的条带,每个引物可扩增出4~16条带,分子量在200~2200bp之间,其中多态位点为156个,占70.27%;群体的Shannon多样性指数为0.2818,Nei基因多样性指数为0.2491;个体间最大遗传距离为0.291,最小遗传距离为0.066。通过与其他贝类遗传多样性的研究结果比较,可初步判断泰国产方斑东风螺养殖群体的遗传多样性比较丰富。     

Genetic relationships among cultivated and wild <Emphasis Type="Italic">Vigna angularis</Emphasis> (Willd.) Ohwi et Ohashi and relatives from Korea based on AFLP markers

Genetic variation and relationships among members of the azuki bean complex (Vigna angularis) including wild (V. angularis var. nipponensis), weedy, and cultivated types (V. angularis var. angularis), V. nakashimae, and rice bean (V. umbellata) from Korea were examined using the Amplified fragment length polymorphism (AFLP) method. AFLP analysis of 50 accessions revealed 333 (72.1%) polymorphic fragments out of 462 fragments amplified using seven primer combinations. The number of polymorphic fragments within each species was 70 in the azuki bean complex and 41 in V. nakashimae, but there was no polymorphism in rice bean. The number of shared fragments among species ranges from 142 between the azuki bean complex and V. nakashimae to 166 between the azuki bean complex and rice bean. Within the azuki bean complex, the range of shared bands was from 231 between cultivated and weedy types to 238 between cultivated and wild types. A dendrogram generated from Jaccard’s similarity matrix was divided into three groups, which correspond to V. nakashimae, azuki bean complex, and rice bean. The relationship between azuki bean and rice bean is closer than between azuki bean and V. nakashimae. Phenetic distances averaged 0.502 between the azuki bean complex and V. nakashimae and 0.467 between the azuki bean complex and rice bean. Within the azuki bean complex, the weedy type was more closely related to wild than cultivated types. But UPGMA dendrogram of the azuki bean complex reveals that each type is not clearly isolated. These results will help to understand genetic diversity and evolutionary dynamics of Vigna in Korea.     

Extent and Pattern of Genetic Diversity for Morpho-agronomic Traits in Ethiopian Highland Pulse Landraces: I. Field Pea (<Emphasis Type="Italic">Pisum sativum</Emphasis> L.)

An experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study the extent and pattern of genetic diversity in Ethiopian field pea (Pisum sativum L.) landraces. One hundred forty-eight germplasm accessions were grown in an alpha lattice design with 2 replications. Data on 12 traits were collected and analyzed. Differences among the accessions were significant for most of the traits (except number of seeds/ pod) at each location even though differences pooled over location were mostly non-significant. The accessions were grouped into five clusters of different sizes. Accessions from the southern part of the country (Arsi) distributed overall clusters while those from the northern half (North and South Wello, North Gonder and North Shewa) fell into clusters C₁ to C₃. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. There was no definite relationship between geographic diversity and genetic diversity as overlapping was encountered in clustering pattern among accessions from different parts of the country. Accessions from different regions might have similar genetic background and those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population. Genetic distances among most of the clusters were significant that crosses between parents selected out of them are expected to generate desirable genetic recombination. Selection should also consider the special advantages of each cluster and each accession within a cluster. Future germplasm collection, conservation and breeding efforts should focus not only on inter-regional diversity but also on intra-regional diversity.     

Extent and Pattern of Genetic Diversity for Morpho-agronomic Traits in Ethiopian Highland Pulse Landraces II. Faba Bean (<Emphasis Type="Italic">Vicia faba</Emphasis> L.)

A field experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study genetic diversity in Ethiopian faba bean (Vicia faba L.) landraces. One hundred sixty random germplasm accessions were grown in an alpha lattice design with two replications. Data on 12 traits were collected and analyzed. Significant differences were observed among the accessions for most of the traits (except number of pods/podding nodes) at each location even though differences pooled over location were mostly non-significant. Cluster analysis distinguished seven diversity classes of different sizes. Accessions from the northern half of the country (North and South Wello, North Gonder and North Shewa) were closely related while those from the southern part of the country (Arsi) were highly diverse. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. Some overlapping were encountered between accessions from the northern and those from the southern parts of the country. The study revealed that accessions from different regions might have similar genetic background and those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population. Genetic distances between most of the clusters were significant that crosses between parents selected out of them are expected to generate desirable progenies. Future germplasm collection, conservation and utilization strategies should put more focus not only on inter-regional diversity in the country as a whole but also on intra-regional diversity in Arsi.