红脂大小蠹传入中国危害特性的变化

通过对山西省灵空山林场与北京小龙门林场的红脂大小蠹危害情况进行详细调查,运用生态位理论对红脂大小蠹选择入侵不同树势油松进行分析,同时查阅陕西、山西、河北、北京等地红脂大小蠹危害的多年历史资料,以此来探讨红脂大小蠹传入中国后危害特性的变化。结果表明：红脂大小蠹传入中国后已由最初危害衰弱木和受伤木的次期性害虫变异为主要危害健康木和轻度衰弱木的初期性害虫,从而为揭示其种群扩张过程、灾害发生机制以及采取相应的控制措施提供了重要的理论依据。     

大豆蚜寄生蜂豆柄瘤蚜茧蜂室内生物学特性观察

豆柄瘤蚜茧蜂Lysiphlebus fabarum( Marshall)是大豆蚜Aphis glycines Matsumura的一种重要寄生蜂.在实验室条件下,对豆柄瘤蚜茧蜂的发育历期、繁殖力、寿命和性比等指标,以及成蜂的羽化、取食、产卵行为等生物学特性进行了观察描述.结果表明:在19 ～31℃范围内,发育历期随着温...     

K55R与ep8叠加突变对扩展青霉脂肪酶热稳定性的改善

利用重叠延伸PCR对扩展青霉脂肪酶(PEL)基因进行体外定点突变,构建了K55R与随机突变体ep8叠加突变的重组质粒pAO815-ep8-K55R。将该质粒电转化引入毕赤酵母(Pichia pastoris)GS115,进行异源表达。实验结果表明:该叠加突变体在毕赤酵母中获得了活性表达,得到表达产物脂肪酶PEL-ep8-K55R-GS。其表达量为508u/mL,分别约为野生型脂肪酶PEL-GS(627u/mL)的81%,随机突变脂肪酶PEL-ep8-GS(924u/mL)的55%;其比活力为2309.1u/mg,与随机突变脂肪酶PEL-ep8-GS和野生型脂肪酶PEL-GS的相仿。叠加突变脂肪酶PEL-ep8-K55R-GS的最适作用温度为37℃,与野生型脂肪酶PEL-GS和随机突变脂肪酶PEL-ep8-GS一致;其Tm值为41.0℃,比野生型脂肪酶PEL-GS提高了2.3℃,比随机突变脂肪酶PEL-ep8-GS提高了0.8℃。表明叠加突变脂肪酶PEL-ep8-K55R-GS的热稳定性有了进一步的提高。     

Changes in normalized difference vegetation index of deserts and dunes with precipitation in the middle Heihe River Basin

AimsPrecipitation is the major water source for desert ecosystems, with its temporal dynamics significantly driving the changes of ecosystem structure and function in desert regions. The objectives of this study are to evaluate the changes in normalized difference vegetation index (NDVI) with seasonal precipitation and different climate years in two cover types (desert and dune).MethodsBased on the daily rainfall dataset of 2000-2012 in the middle Heihe River Basin in Northwest China and the NDVI extracted from the moderate resolution imaging spectroradiometer (MODIS) images, we performed linear regression analysis to examine the correlation of NDVI_INT (accumulated NDVI) with precipitation in two cover types (desert and dune). Two measures of the precipitation are P_c (cool-season precipitation from last September to late February) and P_w (warm-season precipitation in between March and August), while NDVI was characterized with NDVI_INT-pys (previous-year during the different climate years (dry: 2001-2003, wet: 2004-2007)) and the different periods of a growing season (i.e. whole growing season from May through September, early growing season in between May and June, and late growing season in between July and September).Important findings We found that: (1) the determinants of growing season NDVI_INT and their order were NDVI_INT-pys > P_c > P_w for the deserts, while the order was P_w > NDVI_INT-pys for the dunes. The determinants and their order of NDVI_INT in early growing season were NDVI_INT-pys > P_c for the desert, while they were NDVI_INT-pys > P_c = P_w for the late growing season. However, for the dunes, NDVI_INT of the early and late growing season appeared determined by NDVI_INT-pys and P_w, respectively. (2) During the dry and wet periods, precipitation was not a significant factor influencing NDVI_INT for the desert and dune. However, significant increases in NDVI_INTwere observed at dune under wet condition. With the wet years continued, the length of the wet years become an important determinant of NDVI_INT at both cove types, particularly at dune. In addition, it appeared that different changes in NDVI with precipitation existed between the two cover types, but with very similar effects of time-lag. These findings provide useful references for further understanding the mechanisms of NDVI changes with precipitation.     

内蒙古典型草原生长季内不同植物生长动态的模拟

在内蒙古典型草原退化的羊草 大针茅(Leymus chinensis Stipa grandis)群落中,选择不同退化阶段的优势植物羊草(Leymus chinensis)、大针茅(Stipa grandis)、冰草(Agropyron michnoi)、冷蒿(Artemisia frigida),采用Logistic模型分别对其一个生长季内的生长动态及其差异进行模拟和比较研究。主要研究内容和结果如下:①联系资源种群动态模型的一般形式,给出了个体生长模型的数学依据;②通过对Logistic模型进行求解和全面深入的分析,采用数学方法结合生态学理论,将植物生长划分为4个阶段,确定了速生期和突变点;③结合模型分析诠释了模型的物理意义;④对植物的可持续生长期从生态学的角度给出了时间概念上的定义及相应的解释,并由此对草地管理及可持续利用提出了保护建议;⑤通过拟合结果表明,4种植物生长均符合Logistic增长,拟合方程分别为:y=(0.200)/1 e~(2.032-0.060t),y=(1.205)/1 e~(2.608-0.0421t),,y= (0.156)/1 e~(1.858-0.040t),y= (3.177)/1 e~(2.770-0.077t),决定系数均在0.9以上,达到了显著性水平,保证了所求参数的有效性和可靠性;⑥由模型求出了植物的最大生长速度,从大到小依次排列为:冷蒿6.112×10-2(g/(株.d))>大针茅1.267×10-2(g/(株.d))>羊草2.995×10-3(g/(株.d))>冰草1.561×10-3(g/(株.d)),其中冷蒿的最大生长速度是羊草的20倍,大针茅的4.8倍,冰草的39倍;分属于3种不同生活型的羊草、大针茅、冷蒿在生长速度及相应的生长曲线上均存在较大差异,而作为同一生活型(life form)的不同植物相比较,羊草生长速度约为冰草的1.9倍,二者差异不大,在整个生长季内呈现明显相似的动态变化。     

Influence of separate rearing on adult longevity and fecundity of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)

白蜡窄吉丁Agrilus planipennis Fairmaire是近年来发生和危害严重的国际性检疫害虫.为了了解不同饲养条件和种内个体间相互感知对成虫生物学的影响,本研究采用群体饲养、单对饲养、无隔离单雌饲养、视觉隔离单雌饲养和嗅觉隔离单雌饲养等5种处理,在室内测定了白蜡窄吉丁成虫的寿命、取食量、产卵量和产卵历期等参数的变化.结果显示:隔离饲养降低了白蜡窄吉丁成虫的寿命和繁殖力,且不同处理下白蜡窄吉丁成虫的寿命和取食量均存在显著差异(P＜0.05),但产卵量的差异不明显(P＞0.05).其中无隔离单雌饲养时成虫的平均寿命最长,为32.40 d,群体饲养的寿命最短,为20.77 d,且单雌饲养的寿命均比单对饲养和群体饲养的长.单雌饲养的3种情况下,视觉隔离条件下的日均取食量最大,为156.16 mm2,嗅觉隔离的最小,为107.35 mm2;无隔离饲养条件下雌虫的产卵量最大,产卵历期也最长,分别为98.33 d和21.33 d.这些研究结果表明,白蜡窄吉丁种内个体间相互感知的阻断对成虫的取食、发育和繁殖活动存在明显影响,且嗅觉在其种群内的交流活动中作用最重要,其次是视觉.此外,个体之间的相互干扰或竞争对白蜡窄吉丁成虫的寿命和繁殖力也可能存在一定的影响.这为生产上采用隔离措施如营造混交林带防治该虫提供了理论基础.     

朱鹮游荡期的生态观察

本文对朱游荡期的夜宿地、觅食地、日活动行为进行了观察     

Effects of different rotations on carbon sequestration in Chinese fir plantations

Aims Under the context of global climate change, scientific management is the main way to enhance carbon sequestration of plantation forests. A reasonable rotation is one of the intensive management strategies, adjusting forest structure. The decline of productivity after continuous multigenerational cultivation is strongly related to its rotation. Therefore, it is necessary to study the effects of different rotations on carbon sequestration of Chinese fir (Cunninghamia lanceolata) plantations, which can provide a theoretical basis for their sustainable management.
Methods We set up sampling fields of Chinese fir plantations with different age sequences, and used the observation data to test the FORECAST model. We then simulated the effects of different rotations on Chinese fir plantations sequestration using FORECAST model.
Important findings The results showed that over a 150-year period, total carbon sequestration was highest under short rotation length (15-year). However the carbon persistence was poorest and the decline of carbon between each rotation was biggest, indicating an unsustainable management model. Compared with short rotation, the total carbon sequestration under normal rotation (25-year) and long rotation (50-year) was lower. However, the carbon persistence under long rotation was strongest, which was beneficial to maintaining carbon stability during each rotation. Under good site conditions (site index (SI) = 27), the shorter the rotation was, the more severely the soil fertility was consumed. In order to have persistent carbon sequestration rates in Chinese fir plantations, we suggest that rotation should be longer than 25 years. Application of FORECAST model can help quantitatively assess carbon sequestration capacity of forest plantations, which varies under different management strategies.     

UV-B辐射对拟南芥细胞周期G1/S期转变的影响

以同步化的拟南芥（Arabidopsis thaliana）根尖细胞为材料,研究了UV-B辐射对拟南芥细胞周期G1／S期转变的影响。细胞周期荧光显微图像分析表明,UV-B辐射延缓了拟南芥根尖细胞G1／S期的转变。基因表达的RT-PCR检测表明,在UV-B辐射下G1／S期转变的标志基因HistoneH4和E2Fa的表达受抑制,而G1／S期转变的抑制因子KRP2基因表达则受诱导上调。单细胞凝胶电泳检测结果表明,UV-B辐射引起拟南芥根尖细胞内积累大量的环丁烷嘧啶二聚体。以上结果表明,UV-B辐射抑制植物的生长可能受细胞周期和DNA损伤调控。