Using genetic tools to inform conservation of fragmented populations of Asian elephants (Elephas maximus) across their range in China     

Ying CHEN  Yakuan SUN  Mei HUA  Kun SHI  David DUDGEON 《Integrative zoology》2023,18(3):453-468

A herd of 15 Chinese elephants attracted international attention during their 2021 northward trek, motivating the government to propose establishment of an Asian elephant national park. However, planning is hampered by a lack of genetic information on the remaining populations in China. We collected DNA from 497 dung samples from all 5 populations encompassing the entire range of elephants in China and used mitochondrial and microsatellite markers to investigate their genetic and demographic structure. We identified 237 unique genotypes (153 females, 84 males), representing 81% of the known population. However, the effective population size was small (28, range 25–32). Historic demographic contraction appeared to account for low haplotype diversity (H_d = 0.235), but moderate nucleotide and nuclear diversity (π = 0.6%, H_e = 0.55) was attributable to post-bottleneck recovery involving recent population expansion plus historical gene exchange with elephants in Myanmar, Lao PDR, and Vietnam. The 5 populations fell into 3 clusters, with Nangunhe elephants differing consistently from the other 4 populations (F_ST = 0.23); elephants from Mengyang, Simao, and Jiangcheng belonged to a single population (henceforth, MSJ), and differed from the Shangyong population (F_ST = 0.11). Interpopulation genetic variation reflected isolation by distance and female-biased dispersal. Chinese elephants should be managed as 2 distinct units: Nangunhe and another combining Shangyong and MSJ; their long-term viability will require restoring gene flow between Shangyong and MSJ, and between elephants in China and neighboring countries. Our results have the potential to inform conservation planning for an iconic megafaunal species.  相似文献   

Physiological but not morphological adjustments along latitudinal gradients in a human commensal species,the Eurasian tree sparrow     

Qian ZHANG  Mo LI  Yuan YIN  Shiyong GE  Danjie LI  Ibrahim M. AHMAD  Ghulam NABI  Yanfeng SUN  Xu LUO  Dongming LI 《Integrative zoology》2023,18(5):891-905

Human commensal species take advantage of anthropogenic conditions that are less likely to be challenged by the selective pressures of natural environments. Their morphological and physiological phenotypes can therefore dissociate from habitat characteristics. Understanding how these species adjust their morphological and physiological traits across latitudinal gradients is fundamental to uncovering the eco-physiological strategies underlying coping mechanisms. Here, we studied morphological traits in breeding Eurasian tree sparrows (ETSs; Passer montanus) among low-latitude (Yunnan and Hunan) and middle-latitude (Hebei) localities in China. We then compared body mass; lengths of bill, tarsometatarsus, wing, total body, and tail feather; and baseline and capture stress-induced levels of plasma corticosterone (CORT) and the metabolites including glucose (Glu), total triglyceride (TG), free fatty acid (FFA), total protein, and uric acid (UA). None of the measured morphological parameters varied with latitude except in the Hunan population, which demonstrated longer bills than those in other populations. Stress-induced CORT levels significantly exceeded baseline levels and decreased with increasing latitude, but total integrated CORT levels did not vary with latitude. Capture stress-induced significantly increased Glu levels and decreased TG levels, independent of site. However, the Hunan population had significantly higher baseline CORT, baseline and stress-induced FFA levels, but lower UA levels, which differed from other populations. Our results suggest that rather than morphological adjustments, physiological adjustments are mainly involved in coping mechanisms for middle-latitude adaptation in ETSs. It is worth investigating whether other avian species also exhibit such dissociation from external morphological designs while depending on physiological adjustments.  相似文献   

低磷胁迫对红豆草光合、叶绿素荧光及内源激素的影响     

陈洁  南丽丽  汪堃  夏静  何海鹏  马彪  姚宇恒 《草地学报》2023,31(1):112-119

为探究低磷胁迫对红豆草(Onobrychis viciaefolia)光合作用、叶绿素荧光以及内源激素的影响,本试验采用营养液沙培法,以耐低磷5号和磷敏感1号红豆草为试验材料,设置常磷(1.00 mmol·L^-1 KH₂PO₄)和低磷(0.01 mmol·L^-1 KH₂PO₄)胁迫处理,于不同胁迫天数后测定形态、光合以及内源激素含量变化。结果表明：低磷胁迫抑制红豆草生长和光合作用,在低磷胁迫下,除非光化学淬灭系数外,供试红豆草叶绿素荧光参数均下降。随着胁迫时间的延长,2份红豆草材料地上和地下部玉米素(ZT)、脱落酸(ABA)、生长素(IAA)和赤霉素(GA₃)及其之间的比值变化趋势不一致,耐低磷红豆草地上和地下部ZT,GA₃,IAA,ABA耐低磷系数大于磷敏感材料。相关性分析表明,IAA与光合作用和叶绿素荧光显著相关,ABA与IAA,ZT,GA₃呈负相关。研究结果可为红豆草耐低磷特性研究提供...  相似文献   

磷肥对甘肃临夏地区燕麦干草及种子生产的影响     

耿小丽  武慧娟  付萍  刘乾  高占琪 《草地学报》2023,31(3):813-818

为确定甘肃高寒雨养区燕麦(Avena sativa)种子生产中磷肥最佳用量,提高肥料利用效率,试验在氮肥(尿素)用量75 kg·hm^-2的固定水平下,设计4个磷肥(P₂O₅)水平(0(CK),65(C₁),100(C₂),135(C₃)kg·hm^-2),对各磷肥水平下干草产量、种子产量和相关性状的变化进行了研究。结果表明：施用磷肥使燕麦的株高、茎粗、分蘖和干草产量均有提高,灌浆期C₁,C₂,C₃干草产量较CK依次提高13.85%,25.96%,22.65%,干草产量与磷肥水平显著正相关(相关系数0.91);施用磷肥提高了燕麦的有效分蘖数、主穗长,显著提高主穗粒数、穗粒重、千粒重、种子产量和秸秆产量,C₁,C₂,C₃种子产量较CK依次提高12.37%,16.72%,14.38%,种子产量与磷肥水平显著正相关...  相似文献   

饲粮添加过瘤胃半胱氨酸对育成期梅花鹿生长性能、营养物质表观消化率和血清生化指标的影响     

杨乾龙  魏倩倩  赵德辉  郭肖兰  张铁涛  王晓旭  鲍坤  王凯英 《草业学报》2023,32(2):148-159

本试验旨在研究饲粮添加过瘤胃半胱氨酸对育成期梅花鹿生长性能、营养物质表观消化率和血清生化指标的影响。采用单因素随机区组试验设计,将12头7月龄雄性梅花鹿仔鹿分为4组(每组3个重复,每个重复1只),组间体重差异不显著。对照组(Ⅰ组)饲喂基础饲粮,试验组分别饲喂额外添加1.25(Ⅱ组)、2.50(Ⅲ组)和5.00 g·kg^-1(Ⅳ组)过瘤胃半胱氨酸(有效成分51.70%)的试验饲粮。试验预饲期15 d,正试期112 d。结果表明,1)与Ⅰ组相比,添加过瘤胃半胱氨酸Ⅲ组总增重和平均日增重显著提高(P<0.05),Ⅲ组料重比显著降低(P<0.05);2)与Ⅰ组相比,添加过瘤胃半胱氨酸各组粗蛋白质、钙和磷表观消化率显著提高(P<0.05),Ⅲ组干物质和有机物表观消化率显著提高(P<0.05);3)与Ⅰ组相比,添加过瘤胃半胱氨酸Ⅱ组和Ⅲ组甘氨酸表观消化率显著提高(P<0.05),各组半胱氨酸、蛋氨酸、丝氨酸、赖氨酸、苏氨酸、缬氨酸、异亮氨酸、亮氨酸、精氨酸、苯丙氨酸、组氨酸、天冬氨酸、酪氨酸、谷氨酸、丙氨酸和脯氨酸表观消化率显著提高(P<0...  相似文献   

杂交水稻制种提高结实率的研究     

许琨  舒昆 《种子》1997,(1):17-20

杂交水稻制种不同于水稻栽培、其结实由柱头外露结实和非柱头外露结实两部分构成；空壳中90％以上是由于没有授粉受精造成的：90％以上的受精拉都能正常发育结实。柱头外露率和受精率与结实率呈显著正相关。后期施肥、父本大龄秧和机械授粉能有效地提高柱头外露率、花遇优度和结实率及制种产量。  相似文献   

陆地棉品种间杂种苏杂16棉铃发育动态研究   总被引：5，自引：6，他引：5  

徐立华  钱大顺  陈祥龙  张香桂  杨德银 《棉花学报》1996,(2)

棉铃发育过程中，苏杂１６单铃子棉主的提高表现为二个方面：一是纤维干重的增加，１９９１～１９９２两年平均增加１０．０％；二是种子重量的提高，两年平均单铃种仁重增加９．４％。单铃纤维干重的增长与棉铃对位叶大小呈正相关关系，与棉铃对位叶中全Ｎ含量呈负相关关系．该杂文组合在棉铃发育过程中表现了较强的“源”“库”生理优势，光合产物积累多，营养物质运转快是该组合获得高产的重要生理基础。  相似文献   

Data Processing of Motorcycles Coastdown Testing     

XU Zhong-ming  JIN Jie  ZHANG Zhi-fei  MA Yong-zhang  ZHOU Kun 《保鲜与加工》2007,(9):14-16

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Pd Pattern Recognition Based on Linear Discriminant Analysis in GIS     

ZHANG Xiao-xing  TANG Ju  SU Cai-xin  XU Zhong-rong  ZHOU Qian 《保鲜与加工》2006,(10):1-4

According to the character of PD in GIS, the authors design four kinds of GIS defection models. The GIS gray intensity images are constructed based on mass specimens gathered by the ultra - high frequency and high speeds systems, Aiming at the PD characteristics and its defections, A PCA-FDA method is put forward based on PD images. The principal component analysis is employed to condense the dimension of PD images, then the optimal sets of statistically uncorrelated discriminant vectors are extracted, and the minimum distance classifier is constructed as classifier. The identified results show that this method can effectively elevated the discrimination of the four kinds of defects in GIS PD.  相似文献   

Transmission Congestion Management Based on Power Influence Coefficient     

LI Chun-yan  YU Ji-hui  ZHANG Qian 《保鲜与加工》2007,(3):31-35

Basing eliminating on the idea that the generator who has the most influence on the power flow of line is mostly in favor of transmission congestion, the model of congestion management with the object of minimizing adjustments of bufions varied with generation outputs is proposed. It can eliminate the congestion effectively by judging the generators who should be adjusted and the amounts of adjustment. The test on IEEE-RTS24 buses system and other practical systems show that the proposed method is effective.  相似文献