基于SSR标记的贵州野生白三叶遗传多样性分析

采用SSR分子标记技术,对贵州22份野生白三叶(Trifolium repens)样品遗传多样性及亲缘关系进行了研究.结果表明,利用20对SSR引物共扩增出202条带,其中169条带具有多态性,多态性位点达83％;根据SSR标记的多态性计算不同采样地野生白三叶样品之间的遗传距离(GD),22份样品之间遗传距离介于0.140 6～0.630 4之间,说明样品间遗传差异较大;聚类分析结果,当相似系数为0.64时,22份白三叶被分成3类:第1类只有W14,表明W14与其余材料的亲缘关系较远;第2类包括W2、W4、W8、W18居群,表明这4个居群相似性较大,遗传距离较近;第3类包括17个居群,居群间有着复杂的遗传关系.研究结果表明,22份贵州野生白三叶的遗传多样性十分丰富.     

Effects of forage type and gibberellic acid on nitrate leaching losses

Nitrogen (N) leaching from soil into water is a significant concern for intensively grazed forage‐based systems because it can cause a decline in water quality and is a risk to human health. Urine patches from grazing animals are the main source of this N. The objective of this study was to quantify the effect that forage type and gibberellic acid (GA) application had on N leaching and herbage N uptake from urine patches on perennial ryegrass–white clover (RGWC), Italian ryegrass and lucerne. A lysimeter study was conducted over 17 months to measure herbage growth, N uptake and N loss to water beneath each of the three forage types with the following treatments: control, urine (700 kg N/ha) and urine with GA (8 g GA active ingredient/ha). Compared with RGWC (205 kg N/ha), N leaching losses were 35.3% lower from Italian ryegrass (133 kg N/ha) and 98.5% higher from lucerne (407 kg N/ha). These differences in leaching loss are likely to be due to winter plant growth and N uptake. During the winter months, Italian ryegrass had higher N uptake, whereas lucerne had lower N uptake, compared with RGWC. The application of GA had no effect on N leaching losses, DM yield or N uptake of forage treated with 700 kg N/ha urine.     

白三叶对黑麦草、弯叶画眉草的化感作用初探

针对白三叶Trifolium repens与黑麦草Lotium perenne、弯叶画眉草Eragrostis curvula混播时导致后2种植物数量减少甚至消失的现象,通过白三叶的根部、地上部和植株水提液对黑麦草和弯叶画眉草种子进行发芽实验,以及白三叶与黑麦草、白三叶与弯叶画眉草种子混播进行实验,研究表明:白三叶(幼苗、2年生植株根及茎叶)的水提取液在原液以及稀释20倍时对受体植物的胚根和胚芽的生长均产生明显的抑制作用,而在100倍稀释液时表现出一定的促进作用;白三叶与黑麦草及白三叶与弯叶画眉草种子混播实验,表明5∶1的比例为最佳混播比例.     

丛枝菌根真菌接种对白车轴草耐盐性的影响

丛枝菌根真菌(AMF)可与植物共生形成复杂的菌丝网络,影响植物生长及抗逆能力。目前关于AMF对白车轴草耐盐性的影响尚存争议,本研究采用盆栽试验,研究在盐胁迫条件下(NaCl浓度为150 mmol·L^-1),接种AMF对拉丁诺白车轴草耐盐性的影响。结果表明,在盐胁迫条件下,与对照相比,白车轴草的生长与生理指标均受到抑制。盐胁迫下接种AMF后,白车轴草株高、干重、PSⅡ最大光能转换效率和相对含水量均有增加,丙二醛(MDA)含量以及相对电导率有所降低,渗透调节物质均有提高,其中可溶性糖(SS)和游离脯氨酸(Pro)含量分别提高了32.03%和9.42%。说明盐胁迫抑制白车轴草的生长,接种AMF增强了白车轴草抗逆适应能力,促进白车轴草的生长,增加渗透调节物质含量,提高白车轴草耐盐胁迫的能力。     

马蹄金与匍茎翦股颖光合生理生态的比较研究

研究表明，１．通过光饱和点、光补偿点、ＣＯ＿２补偿点及叶绿素ａ／ｂ比值等测定，马蹄金与匍茎剪股颖均属喜光、耐荫的Ｃ＿３植物。马蹄金对强光适应性大于匍茎翦股颖。因而在芜湖地区作为大田草坪种植，则马蹄金优于匍茎葛股颖。２．ＮａＨＳＯ＿３均有增强光合速率、加速光合产物输出、增加于物质积累及提高生物产量的效应。光呼吸抑制剂在草坪生产上大有可为。     

白三叶草中绿原酸的提取及含量测定

采用70％的甲醇溶液为提取剂，索氏提取法对白三叶草中绿原酸进行提取，HPLC法对其中绿原酸进行检测。Luna C18柱（4．6nml×150mm，5μm），流动相为乙腈-0．4％磷酸溶液（体积比1：9），波长327nm，流速1．0mL／min。绿原酸在0．240～3．600μg呈良好线性关系，相关系数r为0．9996。结果表明白三叶草中含有绿原酸且含量较高。     

白三叶(Trifolium repens L)无性系植物分株间的生理整合作用

研究了白三叶无性系植物种群，在相互连接的分株之间生理上相互依存的程度。结果显示子代在生理上取决于母株资源的转移，这一依赖性随时间而下降。相互连接的分株，一部分被遮荫至１０％，而照光分株光合速率明显增加。光被限制期间，分株将重新整合，遮荫分株无性系中由其它分株提供同化物。在子代匍匐茎数目和长度上有一个权衡。当资源受限制时，产生极少较长的子代匍匐茎，结果提高了子代能够占据更有利条件的可能性。在分株之间，生理整合作用降低了子代建立所面临的危险，使同源分株在资源的可利用能力上整合到一个局部的异质环境，增加同源分株间的竞争能力，缓冲所面对的局部微生境的选择。     

Contribution of White Clover Varieties in High-Productivity Systems under Grazing and Cutting

Two medium leaf size varieties of white clover (Trifolium repens L.) were grown in mixture with a range of grass species and varieties in a field experiment conducted over 4 years. The clovers were grown singly or as a blend in swards with a tetraploid perennial ryegrass (Lolium perenne L.), a diploid Italian ryegrass (Lolium multiflorum L.) or tetraploid hybrids between these two species (Lolium x boucheanum Kunth). These grasses were also grown in monoculture. Swards were managed in a regime involving two periods of sheep grazing, two periods of cattle grazing and a silage cut in the same year for 4 years. The objectives of this experiment were 3‐fold: (1) to examine the yield and persistency of white clover in highly productive systems with modern perennial, hybrid and Italian ryegrasses; (2) to compare the performance of white clover varieties grown singly in mixture with grasses with their performance together as a blend, and (3) to examine the persistency of new Italian ryegrass varieties, exemplified by AberComo. The clover content of the sward remained high throughout the experiment, with a mean of 31 % overall. Differences in clover yield between plots were largely attributable to the effects of companion grasses. Total yields were very similar in plots containing different clover varieties and in plots where these varieties had been grown singly or as a blend. Grass yields in mixture were greater than those in monoculture but showed similar relative rankings. The diploid Italian ryegrass variety AberComo showed an unexpectedly high yield in the 4th year of the experiment. The implications of these results for strategies for productive, sustainable agriculture using modern white clover and ryegrass varieties are discussed.     

马蹄金叶斑病发生与室内药剂毒力测定

通过对马蹄金叶斑病病原菌的分离、培养等研究,按照柯赫氏法则确定此病由胶孢炭疽菌和交链孢引起的.室内药剂毒力测定实验表明,保鲜克和百菌清对炭疽菌和交链孢菌丝的扩展蔓延作用较好,代森锌和退菌特对炭疽菌和交链孢的孢子萌发有较好的抑制作用.     

苗期46份偃麦草种质材料耐盐性综合评价

采用盆栽苗期模拟盐胁迫的方法,对不同NaCl胁迫下46份偃麦草种质材料的地上生物量、地下生物量、叶片枯黄率进行测定,并对其耐盐性进行综合评价。结果表明,随盐浓度的增加,偃麦草的地上生物量、地下生物量的响应机制并不一致,而叶片枯黄率则呈现上升趋势;46份偃麦草种质耐盐性存在较大的差异,地上生物量、地下生物量、叶片枯黄率半致死盐浓度变异系数依次为42.48%~43.37%,26.9%~38.6%,18.98%;隶属函数综合分析认为,偃麦草材料的耐盐性从强到弱依次为E35、E14、E42、E25、E31、E26、E39、E36、E41、E22、E15、E21、E19、E34、E38、E16、E44、E02、E03、E37、E07、E18、E49、E46、E10、E48、E30、E04、E06、E08、E50、E24、E17、E27、E43、E40、E29、E28、E32、E11、E33、E23、E09、E13、E01、E12。