四川盆地浅丘陵区农林复合系统内部天空散射辐射分布特性理论分析

根据四川盆地浅丘区农林复合系统特点,从理论上分析了该系统内天空散射辐射令布特征。提出了在林带和地形(坡度变化)的双重影响下的林带间平均相对辐照成分布特征,为农林复合系统的设计提供了依据;除林带本身产生“光胁地”外,地形变化即坡度的增加,叶“光胁地”效应有增强作用,对其范围有扩大作用。     

不同密度杉木林内辐射与叶面积垂直分布对生长的影响

本文通过对八年生杉木人工林内太阳辐射与叶面积垂直分布的观测与研究，用计算机绘图与计算，得出以下结果：杉木叶面积的垂直分布和叶面积指数与密度有关，冠形因密度增加由圆锥形变为圆柱形，叶面积指数是先上升后下降。杉木林内辐射的消减随密度的增加而加剧，在冠层深3／4处趋于平缓，当郁闭度低于0．85时，林冠下辐射有回升，用累加叶面积指数分层计算林冠消光系数，可减少因叶片分布不均匀而产生的误差，用累计值计算辐射，可简化观测与计算，用辐射吸收率、叶面积指数，杉木个体生物量及年均生物增长量4个指标对杉木林生长作综合评价，八年生杉木林生长的较适宜工是2m×1m。     

Effects of enhanced ultraviolet-B radiation on water use efficiency, stomatal conductance, leaf nitrogen content and morphological characteristics of Spiraea pubescens in a warm-temperate deciduous broad-leaved forest

Spiraea pubescens, a common shrub in the warm-temperate deciduous forest zone which is distributed in the Dongling Mountain area of Beijing, was exposed to ambient and enhanced ultraviolet-B (UV-B, 280–320 nm) radiation by artificially supplying a daily dose of 9.4 kJ/m² for three growing seasons, a level that simulated a 17% depletion in stratospheric ozone. The objective of this study was to explore the effects of long-term UV-B enhancement on stomatal conductance, leaf tissue δ ¹³C, leaf water content, and leaf area. Particular attention was paid to the effects of UV-B radiation on water use efficiency (WUE) and leaf total nitrogen content. Enhanced UV-B radiation significantly reduced leaf area (50.1%) but increased leaf total nitrogen content (102%). These changes were associated with a decrease in stomatal conductance (16.1%) and intercellular CO₂ concentration/ air CO₂ concentration (C _i /C _a) (4.0%), and an increase in leaf tissue δ ¹³C (20.5‰), leaf water content (3.1%), specific leaf weight (SLW) (5.2%) and WUE (4.1%). The effects of UV-B on the plant were greatly affected by the water content of the deep soil (30–40 cm). During the dry season, differences in the stomatal conductance, δ ¹³C, and WUE between the control and UV-B treated shrubs were very small; whereas, differences became much greater when soil water stress disappeared. Furthermore, the effects of UV-B became much less significant as the treatment period progressed over the three growing seasons. Correlation analysis showed that enhanced UV-B radiation decreased the strength of the correlation between soil water content and leaf water content, δ ¹³C, C _i/C _a, stomatal conductance, with the exception of WUE that had a significant correlation coefficient with soil water content. These results suggest that WUE would become more sensitive to soil water variation due to UV-B radiation. Based on this experiment, it was found that enhanced UV-B radiation had much more significant effects on morphological traits and growth of S. pubescens than hydro-physiological characteristics. __________ Translated from Journal of Plant Ecology, 2006, 30(1): 47–56 [译自: 植物生态学报]     

COMBINATION OF RADIATION THERAPY AND FIROCOXIB FOR THE TREATMENT OF CANINE NASAL CARCINOMA

Carcinomas represent two‐thirds of canine nasosinal neoplasms. Although radiation therapy (RT) is the standard of care, the incidence of local recurrence following treatment is high. Cyclooxygenase‐isoform‐2 (COX‐2) is expressed in 71–95% of canine nasal carcinomas and has been implicated in tumor growth and angiogenesis. Accordingly, COX‐2 inhibition seems rational to improve outcome. Dogs with histologically confirmed, previously untreated nasal carcinomas were randomized to receive the combination of a selective COX‐2 inhibitor (firocoxib) and palliative RT (Group 1) or RT and placebo (Group 2). Patients were regularly monitored with blood tests, urinalysis, and computed tomography. Pet owners were asked to complete monthly a quality‐of‐life questionnaire. Twenty‐four dogs were prospectively enrolled. According to Adams modified system, there were five stage 1, five stage 2, three stage 3, and 11 stage 4 tumors. Two dogs had metastases to regional lymph nodes. Median progression‐free interval and overall survival were 228 and 335 days in Group 1 (n = 12) and 234 and 244 days in Group 2 (n = 12). These differences were not statistically significant. The involvement of regional lymph nodes was significantly associated with progression‐free interval and overall survival (P = 0.004). Quality of life was significantly improved in Group 1 (P = 0.008). In particular, a significant difference was observed for activity and appetite. Although not providing a significant enhancement of progression‐free interval and overall survival, firocoxib in combination with RT is safe and improved life quality in dogs with nasal carcinomas.     

乙酰化处理对樟子松木材耐光性和热稳定性的影响

【目的】探讨乙酰化处理对人工林木材耐光性和热稳定性的影响,为木材颜色调控技术及高耐光染色木材的研发提供理论依据。【方法】以樟子松木粉为试样,加入乙酸酐和二甲苯溶液,在120℃条件下分别反应5,10,20,40,60 min,测试乙酰化处理时间对木粉增重率的影响;分别称取1 g经不同时间乙酰化处理的木粉和未处理木粉,置于 UV老化试验箱内辐射100 h,利用红外光谱分析 UV辐射前后乙酰化木粉化学官能团的变化,通过热重和扫描电镜分析乙酰化木粉的热稳定性及其形貌变化。【结果】随着乙酰化处理时间的延长,樟子松木粉的增重率呈现先增加后降低的趋势,在处理40 min 时木粉增重率最大;乙酰化木粉在1741 cm －1和1385 cm －1处的CO,C—H特征吸收峰强度均大于原木粉,处理时间40 min 时木粉的吸收峰强度最大;UV 辐射后,乙酰化木粉在1508 cm －1处木质素苯环特征吸收峰强度明显大于原木粉,处理时间40 min 时木粉的吸收峰强度最大,表明木粉经乙酰化处理后光稳定性得到提升;热重分析显示,经乙酰化处理后,木粉热分解所需的温度明显提高,表明乙酰化木粉的热稳定性好于原木粉;扫描电镜分析表明,乙酰化处理可增强木粉微观构造抵抗光劣化的能力。【结论】乙酰化处理能有效抑制樟子松木材的光降解反应并提升其热稳定性。     

不同熟期夏玉米品种生长发育特性与产量形成的关系

【目的】研究不同熟期夏玉米品种生长发育特性与产量形成的关系,以期为早熟、高产、适应机械粒收的玉米新品种的筛选提供理论依据。【方法】2017年以早熟玉米品种登海518（DH518）、衡早8号（HZ8）和中晚熟玉米品种登海605（DH605）、郑单958（ZD958）为试验材料,2018年以早熟玉米品种登海518（DH518）、京农科728（JNK728）和中晚熟玉米品种登海605（DH605）、郑单958（ZD958）为试验材料,种植密度为75 000株/hm²,研究玉米生长发育过程中的叶片建成规律、穗部发育特性以及各生育阶段对光温需求的差异。【结果】不同熟期夏玉米品种各生育阶段的光温需求大小表现为吐丝期（R1）—生理成熟期（R6）>出苗期（VE）—吐丝期（R1）>播种期（sowing）—出苗期（VE）。不同品种花后对积温的需求高于花前,中晚熟和早熟夏玉米品种对积温需求的差异主要在拔节期—吐丝期,具体表现为第9—16片叶建成期;花后对积温的需求品种间差异不显著。相关性分析表明,不同熟期夏玉米品种的产量与穗位高、穗高系数呈极显著正相关关系。不同熟期夏玉米品种的雄穗发育特性不同,晚熟品种的雄穗长度显著低于早熟品种,但晚熟品种的雄穗分枝数、雄穗总小花数、小花败育率、有效小花数显著高于早熟品种;而雌穗分化到籽粒形成受品种基因型影响较大。【结论】不同熟期夏玉米品种生长发育特性具有较大差异,在75 000株/hm²条件下,中晚熟品种的产量显著高于早熟品种;植株总叶片数较少,拔节期—吐丝期所需时间短,后期脱水速率快是早熟宜机收玉米品种的典型特征。     

UV-B辐射和施氮对满江红生长、矿质营养和抗氧化生理的影响

为探讨UV-B辐射和施氮对满江红（Azolla）生长、矿质营养和抗氧化生理的影响,以元阳梯田稻田满江红为材料,室内模拟UV-B辐射（0 kJ·m^-2与5.0 kJ·m^-2）和施N处理（无氮和0.06 g·L^-1氮）,研究其对满江红生长、矿质营养和抗氧化生理的影响。结果表明,与CK （0 kJ·m^-2、无氮）相比,UV-B+N（5.0 kJ·m^-2、0.06 g·L^-1氮）、UV-B辐射（5.0 kJ·m^-2、无氮）处理均显著降低满江红光合色素含量,抑制其生长,导致生物量显著下降。UV-B辐射与施N单独或复合处理均显著增加满江红的N含量与累积量,降低植株Mg、Ca的含量。UV-B辐射与施N单独或复合处理均显著增加满江红丙二醛（MDA）含量,提高超氧化物歧化酶（SOD）、谷胱甘肽还原酶（GR）活性,降低类黄酮含量和过氧化物酶（POD）活性。此外,UV-B辐射导致满江红抗坏血酸（AsA）含量下降、总酚含量增加,UV-B辐射与N处理显著增强满江红的总抗氧化能力。相关性分析发现,类黄酮、类胡萝卜素含量与生物量呈显著正相关。双因素分析表明,UV-B辐射显著增加了满江红氮、总酚、MDA含量,提高SOD、GR活性与总抗氧化能力; N处理显著增加AsA、MDA含量及SOD、GR活性; UV-B+N处理对满江红的生长系数、生物量、磷、钙、镁、叶绿素a、类胡萝卜素、AsA、总酚和类黄酮含量及POD、SOD活性和总抗氧化能力的影响存在交互作用。综上,UV-B辐射增强会抑制满江红生长,导致满江红N含量与累积量增加,施氮不能缓解UV-B辐射对满江红生长的抑制效应。     

太阳辐射作用下浮顶油罐温度场的数值模拟

为了研究太阳辐射对浮顶油罐温度场的影响,有必要掌握受太阳辐射影响原油在浮顶油罐中的温度变化规律。通过分析浮顶油罐与环境换热过程,建立2×10^4 m^3浮顶油罐的三维模型,对一天内浮顶油罐油品及罐壁的温度变化进行数值模拟。结果表明:在以太阳辐射为主的环境变化影响下,浮顶油罐的近壁面和浮盘处会产生温度梯度较大的高温油层,深层油品温度受到的影响较小。结合模拟结果,提出了考虑太阳辐射时,在不同条件下使用不同罐壁温度计算公式的建议,从而降低浮顶油罐容积的修正误差。     

The mbuna cichlids of Lake Malawi: a model for rapid speciation and adaptive radiation

Mbuna, the dominant fishes on the rocky shores of Lake Malawi, have become a major ‘model system’ for the study of rapid speciation and adaptive radiation. At least 295 putative species are known, of which more than 200 remain undescribed. There is no good evidence for monophyly in the mbuna, rather mitochondrial DNA phylogenies indicate that they are polyphlyetic with respect to benthic feeding cichlids of the genera Aulonocara, Alticorpus and some species of Lethrinops. Male mbuna hold territories for 18 months or more and breed year‐round. All species are maternal mouthbrooders, but females do not guard free‐swimming young. Mbuna are polygamous (both sexes). There is sexual dimorphism in size, colour and fin length, and many species show within‐population colour polymorphism. Mbuna genera are largely differentiated on the basis of head, jaw and tooth morphology, but congeneric species are generally distinguished by male colour. Many morphologically specialized forms have broad diets and often feed on common easily obtainable resources. While it is likely that dietary and habitat niche partitioning contributes to species coexistence, this has never clearly been demonstrated under experimental conditions. Populations on spatially separated habitat patches are often genetically differentiated, probably because most species are specialized for life on rocky shores, and lack a dispersal phase in their life histories. Males seem to disperse more than females, but are able to home several kilometres back to their territories. Some closely related ecologically equivalent allopatric populations are differentiated in male colour. Those tested have been shown to mate at least partially assortatively. Sexual selection acting on male colour seems the most plausible mechanism for initial species divergence. The same colour forms seem to have arisen several times, suggesting frequent parallel evolution. The main conservation threat to mbuna at present seems to be translocation of species within the lake as a result of the aquarium trade. However, deleterious effects on indigenous populations are not documented. In the long run, sedimentation, pollution, introduction of alien species and the development of targeted food fisheries could be more serious threats.     

Estimating theoretical radiation‐use efficiency for kale crops

Establishing the radiation‐use efficiency (RUE) of forage brassica crops will aid our understanding of their photosynthetic performance. The concept of RUE has been developed for cereals and legumes, but there is limited information for forage brassica crops. Three experiments defining the influence of different sowing dates on ‘Gruner’ kale (Brassica oleracea acephala L.) dry matter production were conducted at Hastings (Hawkes Bay) and Lincoln (Canterbury) in New Zealand between 2002 and 2009. These trials were also evaluated for radiation interception and RUE. Delayed sowing increased RUE in two out of three experiments across sites: from 1·93 g MJ^?1 photosynthetically active radiation (PAR) for December‐sown crops to 2·72 g MJ^?1 PAR (P < 0·001) for January‐sown crops at Hastings and from 1·50 for September‐sown crops to 2·00 g MJ^?1 PAR (P < 0·001) for November‐sown crops at Lincoln. The different sowing dates and years of experimentation provided a range of mean temperatures (from 13 to 16°C) during the vegetative period. Across years and sowing dates, RUE was strongly correlated with mean temperature (R² = 0·81) and sowing date (R² = 0·64), but weakly correlated with season length (R² = 0·11) and dry matter (R² = 0·002). There was also a strong correlation (R² = 0·83) between sowing date and mean temperature. The increase in RUE with delayed sowing was therefore mainly attributed to increased mean temperatures. Radiation‐use efficiency increased at about 0·41 g MJ^?1 for each 1°C increase from 13 to 16°C.