利用草地基况法对宁夏长芒草典型草原进行健康评价研究

以宁夏固原云雾山草原自然保护区为中心,向外呈辐射状布设监测调查样方,利用草地基况法对宁夏长芒草典型草原进行健康评价.结果表明:云雾山、月亮山和南华山的草地处于健康状态；原州区、彭阳县、隆德县、西吉县和盐池县的草地处于健康但有问题状态；海原县和同心县的草地处于不健康状态.     

Study on the Phenotypic Mutation Generated from ~(60)Coγ-ray Irradiated Oxlias triangularis Purpurea Regeneration System

Mutations induced from tissue culture are easily to be separated,which might be propagated in the same medium,especially for the color-leaf ornamental grass,Oxalis triaggularis purpurea.Mutations of the ornamental traits in the tissue culture bottle could be investigated easily.The 35 d regeneration system group showed the lowest adventitious bud number and adventitious root number among 4 inoculation dates by 50 Gy dose of ~(60)Coγ radiation.More studies were carried out based on the 35d differentiation state of O.triangularis purpurea regeneration system.The 35 d regeneration system was then irradiated by 10,25 and 50 Gy doses of ~(60)Coγ rays.Numbers of adventitious buds and roots induced from the regeneration system were cut down with the increment of radiation doses.Seedling length was not distinctly reduced at the absorbed doses of 10 and 25 Gy,but reduced distinctly under 50 Gy of ~(60)Coγ irradiation.The optimal irradiation dose for 35 d O.triangularis regeneration system survival and mutation induction was approximately 25 Gy.The M_2 phenotypic mutation rate was 2.9%,especially,and the leaf number mutation accounted for 76%of the total mutation.The phenotypic mutations,especially in the 10 Gy group,on 0.1 m M Vc containing MS medium were recovered,which indicated that ROS plays a key role in the phenotypic mutation induced by ~(60)Coγ -rays.     

Acaricidal effects of cardiac glycosides, azadirachtin and neem oil against the camel tick, Hyalomma dromedarii (Acari: Ixodidae)

The cardiac glycoside, digitoxin, from Digitalis purpurea L (Scrophulariaceae), a cardiac glycosidal (cardenolide) extract from Calotropis procera (Ait) R Br (Asclepiadaceae), azadirachtin and neem oil from Azadirachta indica A Juss (Meliaceae) were tested for their effects against larvae and adult stages of the camel tick, Hyalomma dromedarii Koch (Acari: Ixodidae). The contact LC50 values of the first three materials against adults were 4.08, 9.63 and >40.7 microg cm(-2), respectively, whereas the dipping LC50 values of the four materials were 409.9, 1096, >5000 and >5000 mg litre(-1), respectively. Contact and dipping LC50 values of the extract and azadirachtin against larvae were 6.16, >20.3 microg cm(-2) and 587.7 and >2500 mg litre(-1), respectively. Azadirachtin had no effects on egg production or feeding of adults up to 5000 mg litre(-1); however at 2500 mg litre(-1), it caused significant reduction in feeding activity of larve, prolonged the period for moulting to nymphal stage, and caused 60% reduction in moultability. Results of the two cardiac glycoside materials are comparable with those of several commercial acaricides. The risks and benefits associated with the use of cardiac glycosides are considered.     

红菜薹自交不亲和性快速测定初报

红菜薹的自交不亲和性表现为柱头抑制。授粉后24h的柱头,在电镜和荧光镜下观察,即可对其不亲和性进行测定。有些单株老龄花亲和性比幼龄花亲和性稍高。亲本亲和指数同后代条和指数的平均值呈正相关,因此在选择时,最好选择那些亲和指数低,不亲和性强的单株。     

宁夏草原针茅属植物群落物种多样性和生产力格局及影响因素研究

物种多样性和生产力是草地生态系统的核心指标,是实现草地生态系统服务与功能的根本所在.宁夏温性草原位于干旱与半干旱的过渡区,针茅属植物是其优势种群,对水热变化敏感;因此,在全球气候变化背景下,探讨宁夏草原针茅属植物群落物种多样性与生产力的格局,在宏观尺度揭示其影响因素,不仅在生态学理论研究中具有重大价值,而且对宁夏天然草...     

不同倍性紫锥菊的性状比较及新种质的获得

采用同株系二倍体、四倍体、八倍体紫锥菊进行大田栽培试验,比较不同倍性紫锥菊的营养生长、生殖生长及多酚类成分指标,八倍体母株种子萌发后通过根尖染色体计数法进行倍性分析,以期为遗传基础理论研究和育种提供更多的材料选择。结果表明:随着倍性增加,株高变矮,叶长宽比和舌状花长宽比变小;每株分枝数以四倍体最高;一年生时二倍体的头状花序数和总花序数最多,显著高于四倍体和八倍体;二年生时四倍体的头状花序数和总花序数最多,显著高于二倍体和八倍体;二年生采收数据紫锥菊四倍体全株产量较八倍体高232.6%,二倍体全株产量较八倍体高187.1%;四倍体和八倍体的地上部、地下部总多酚含量、绿原酸含量、菊苣酸、单咖啡酰酒石酸含量均显著较二倍体高,八倍体地上部和地下部绿原酸含量、地上部菊苣酸含量显著高于四倍体;八倍体子代实生苗倍性鉴定得到五倍体和非整倍体。对紫锥菊而言,八倍体倍性太高,其产量和品质的综合性状不具备优势,但在作为种质资源方面具有价值;四倍体表现优良,较二倍体效益高;获得的五倍体和非整倍体材料,在生产和作为遗传改良桥梁种方面具有价值,是紫锥菊整倍性和非倍性材料创建的有益补充。     

川西亚高山岷江冷杉和紫果云杉径向生长对气候因子的响应

【目的】探讨川西亚高山地区各海拔生境处岷江冷杉和紫果云杉径向生长对气候因子的响应,为进一步揭示当地森林对气候变化的响应机制提供依据。【方法】分别获取王朗自然保护区中海拔与高海拔生境处岷江冷杉和紫果云杉的标准年表,分析年表同气候因子间的关系。【结果】中海拔生境处岷江冷杉生长在1990年后与年均气温存在一定程度的“分离效应”;中海拔生境处岷江冷杉和紫果云杉生长与上年生长季(上年7月和8月)气温和上年生长季末(上年10月)降水量显著负相关( P <0.05),岷江冷杉生长与当年9月气温和降水量显著负相关( P <0.05),紫果云杉生长与当年2、6月月均最低气温显著正相关( P <0.05);高海拔生境处岷江冷杉和紫果云杉生长均与当年生长季前(上年11月、当年1月、当年2月)、当年生长季(当年7月)和上年生长季(上年6月)气温显著正相关( P <0.05),岷江冷杉生长还与当年6月份的降水量及上年8月份的气温显著负相关( P <0.05);滑动相关分析和年表特征年气候分析结果充分印证了各年表对月气候因子响应的可靠性。【结论】上年生长季气温的“滞后效应”对中海拔生境处的岷江冷杉、紫果云杉以及高海拔生境处的岷江冷杉生长均有显著影响;近几十年来,上年生长季末降水对中海拔生境处的岷江冷杉、紫果云杉以及高海拔生境处的紫果云杉生长都具有稳定而显著的抑制作用。     

大针茅繁殖的生态生物学特性

根据对大针茅（Ｓｔｉｐａｇｒａｎｄｉｓ）繁殖的研究和分析，本文提出：生殖枝分化比例低，种子产量和埋藏率低，幼苗成活率低是大针茅有性繁殖微弱的主要原因。这种情况在退化群落更加严重。大针茅在春季不形成分蘖芽，１个分蘖枝条在秋季可在基部形成２～４个分蘖芽，枝条分蘖比率和每个枝条形成的分蘖数在群落退化后变化不明显。但株丛的大小，种群的密度和大针茅的竞争力都大大降低。围栏保护后大针茅依赖营养繁殖迅速恢复。     

青海湖地区紫花针茅型中度与重度退化草地地下植物量的比较研究

对青海湖地区紫花针茅型中度与重度退化草原地下植物量进行了比较研究,结果表明,中度与重度退化样地地下植物量的季节积累动态并不相同,随着退化程度加重,在草地植物地上部枯黄之前,光合产物向地下部的运转减少,根部贮藏的营养物质减少,地下与地上植物量的比值随退化程度的加重而增大。两个退化样地地下植物量的80%分布在0~20 cm土层,用y=axb能够很好描述中度与重度样地在生长季各土层平均分布的植物量及其所占比例。在40 cm深的土层中,中度与重度退化样地地下植物量每年的净生产量分别为849.6 g/m21、346.05 g/m2;周转值分别为32.45%、51.93%。     

原始林内紫果云杉种群的 数量动态

本文将紫果云杉种群看作是由不同径级林木所组成的群体，借以Leslie矩阵描述其数量动态情况，由此得种群Leslie矩阵的特征根λ＝1．028，对应特征向量亦即种群稳定的级径组成为：（9941，783，556，393，280，116，32，8）。结果表明：在原始林内，紫果云杉种群结构较为稳定，呈增长稳定型；经预测，种群未来的结构组成与现在的相似。