红壤坡地农业景观(旱季)地表界面水分传输研究——Ⅱ．叶面冠层一大气界面水分传输

定位观测红壤坡地典型作物系统叶面冠层 大气界面水分传输结果表明 ,叶面冠层 大气界面水汽传输通量大小取决于景观植物群落的构建 ,稳定群落叶面冠层 大气界面水汽传输通量有明显日变化规律 ,除受植物生理机制影响外 ,还明显受土壤水分和气象条件的影响。植株叶片蒸腾速率有明显日变化规律且呈单峰型曲线及多峰态势。净辐射、空气饱和水汽压差、气温、地表温度、风速对蒸腾的影响均达极显著水平 (正相关 ) ,其中净辐射、气温为主要影响因子。叶片气孔导度可反映叶片蒸腾速率 ,叶片气孔阻力日变化规律是植物对气象条件的响应 ,且受土壤水分状况强烈影响。改善作物生长环境 ,调节气孔行为 ,进而协调作物蒸腾作用和光合作用耗水制约 ,可调控叶面冠层 大气界面水分传输 ,提高作物水分利用效率     

重庆缙云山不同林分耗水动态特征及其环境影响因素

以重庆缙云山为试验站点,于2018年1—12月,采用LI-6400 XT便携式光合测定系统测定了针阔混交林、常绿阔叶林和毛竹林3种典型林分耗水动态特征,定量分析了不同林分蒸腾、蒸发水分利用效率与环境因子的关系。结果表明:缙云山不同林分土壤蒸发量呈"几"字形变化规律,在7—8月达到最大,4—6月呈急剧增加趋势;9月以后不同林分土壤蒸发量有所降低,相同月份土壤蒸发基本表现为针阔混交林毛竹林常绿阔叶林。缙云山不同林分蒸腾速率呈单峰型曲线,1—6月属于缓慢增加趋势,在7—8月达到最大,8月以后急剧降低,11—12月基于平稳趋势,相同月份蒸腾速率基本表现为常绿阔叶林针阔混交林毛竹林。不同林分蒸腾速率日变化规律呈单峰型曲线,从早上6:00开始,不同林分叶片蒸腾速率随着一天内光合有效辐射强度的增加、气孔开放而急剧增加,在8:00达到最大值,随后蒸腾速率缓慢降低,相同时间蒸腾速率基本表现为常绿阔叶林针阔混交林毛竹林。缙云山不同林分水分利用效率与蒸腾速率变化趋势相一致,二者呈显著的线性关系(p0.05)。不同林分水分利用效率生理生态因子的相关系数高于蒸腾速率与各生理生态因子的相关系数,其中蒸腾速率和水分利用效率与气孔导度(Gs)、光合有效辐射强度(PAR)均呈显著或极显著的正相关,与空气相对湿度(RH)没有显著的相关性(p0.05),Gs和PAR对不同林分的蒸腾速率和水分利用效率贡献最大。回归分析表明,不同林分蒸腾速率和水分利用效率与生理生态因子间有线性关系,影响不同林分的蒸腾速率和水分利用效率的主导因素包括Gs和PAR。     

环境因子对海防林土壤呼吸速率的影响

 为了揭示土壤呼吸的日间变化规律,寻找影响土壤呼吸速率强弱的生态因子,从而为海防林的造林营林技术提供重要依据,对胶南沿海混交林和灌木林的土壤呼吸速率及各环境因子进行研究。2种海防林林地土壤呼吸速率的日变化均呈现出单峰式的变化规律,灌木林的土壤呼吸速率明显高于混交林。地表温度是对土壤呼吸速率影响最大的环境因子之一,它与混交林和灌木林的土壤呼吸速率分别呈极显著和显著正相关关系。空气相对湿度与混交林土壤呼吸速率呈显著负相关,风速与灌木林土壤呼吸速率呈显著负相关。通过主成分分析和多元线性回归方法,得到了影响海防林土壤呼吸速率的主要环境因子及与土壤呼吸速率之间的多元回归模型。     

环境因素对紫花苜蓿叶水势与蒸腾速率影响的初步研究

植物叶水势及其蒸腾速率除取决于本身的生物学特性外,还受外界环境因子所制约.该文根据有关田间试验资料全面分析了叶水势、蒸腾速率在不同灌溉水平下的日变化规律,并探讨了其与土壤含水率和气象因素(气温、净辐射和饱和差)之间的关系,建立了叶水势和蒸腾速率与气象因素间的定量关系式,对紫花苜蓿的合理灌溉具有指导意义.     

不同环境因子对西洋参蒸腾特性的影响研究

试验研究不同环境因子对西洋参叶片蒸腾特性的影响结果表明 ,环境温度与湿度变化明显影响西洋参叶片蒸腾速率和气孔导度的变化。西洋参植株生长势与叶片蒸腾速率、气孔导度的变化关系密切 ,健壮西洋参植株叶片蒸腾速率与气孔导度及叶片气孔开张度对逆境的适应性和自调控能力均高于纤弱植株。晴天参棚 17.5 %、2 5 .8%和 35 .4 % 3种透光率下西洋参叶片蒸腾速率的日变化不同 ,表现为午前高峰型、午间高峰型和双峰型 ;夏季强光高温条件下气孔导度和气温是影响西洋参叶片蒸腾速率变化的最主要因子。     

喀斯特峰丛洼地4种典型植物蒸腾作用及其影响因素

[目的]对广西壮族自治区喀斯特峰丛洼地4种典型植物(甘蔗、五节芒、灰毛浆果楝和青冈)蒸腾作用及其影响因素进行研究,为进一步开展区域植被生态需水研究提供科学依据。[方法]于2015年4月至2016年1月对4种主要植物群落不同季节蒸腾速率(Tr)、叶面积指数(LAI)和相关环境因子开展现场观测。[结果]4种植物Tr夏季与春、秋、冬3季呈极显著差异(p0.01),不同植物类型其Tr也存在差异,其中,甘蔗Tr的季节变化为96.55~197.42g/(m2·h),五节芒为95.26~169.13g/(m2·h),灰毛浆果楝为97.20~239.11g/(m2·h),青冈四季Tr为81.65~124.42g/(m2·h)。4种植物Tr均与空气温度(Ta)呈极显著(p0.01)或显著正相关关系(p0.05),与土壤含水率(SWC),LAI,土壤容重(ρb),空气相对湿度(RH)呈显著或极显著相关关系。SWC和Ta对甘蔗Tr起主导作用,是主要决策变量;Ta是五节芒Tr的主要决策变量;SWC和ρb是灰毛浆果楝Tr的主要影响因子;LAI,SWC和Ta是青冈Tr的主要影响因子。[结论]研究区域4种典型植物蒸腾作用存在差异,且均呈季节性变化趋势,不同植物Tr影响因素不同,可通过人工诱导水、光、热等环境因子进而合理调控植被生态需水。     

几种沙漠植物蒸腾作用特性及其环境响应机制的研究

对库布齐沙漠2，3，4年生人工梭梭，4年生人工沙枣、柠条以及天然植物油蒿，进行了蒸腾速率与相关环境因子气温、大气相对湿度和0～160cm土层的土壤含水率的测定。结果表明：不同植物种其蒸腾特征各异；气温和大气湿度与蒸腾速率日进程的变化趋势总体表现出随着气温的升高（或大气相对湿度的降低），蒸腾速率亦呈升高的趋势。几种植物蒸腾速率的季节变化总体表现出随着土壤含水率的增加而增加，降低而降低。蒸腾速率与土壤含水率季节变化的相关性因植物种而异。几种植物中油蒿10～100cm层土壤含水率和2年生梭梭、3年生梭梭0～130cm层土壤含水率与蒸腾速率呈直线相关，相关系数分别为0．811，0．694和0．955（P=0．05），而沙枣、柠条和4年生梭梭的蒸腾速率与土壤含水量的相关性不显著。这表明，在天然降水条件下，植物蒸腾作用的季节变化趋势不仅受土壤水分的影响，还与植物自身生长节律和生理调控等其它因素有关。     

不同灌木树种蒸腾速率时空变异特征及其影响因子的研究

在测定4个水土保持灌木树种不同时期蒸腾速率及其影响因子的基础上,对不同树种蒸腾速率的时空变异特征进行了研究,并对蒸腾速率与其影响因子的关系进行了相关分析和多元回归分析。研究结果表明,4种灌木蒸腾速率日变化总趋势为清晨较小,在中午12:00左右基本达到峰值,至18:00左右降至低谷,不同树种日变化有一定差异;旱季4种灌木蒸腾速率的大小顺序为黄荆>黄栌>连翘>绣线菊;雨季4种灌木蒸腾速率的大小顺序为黄荆>绣线菊>连翘>黄栌。4种灌木蒸腾速率的季节变化趋势基本相同,均在5月份呈降低趋势,从6月初又逐渐回升,在7月中旬达到最大值后回落。蒸腾速率在空间上的变化特征是上部最大,中部次之,下部最小。4种灌木的蒸腾速率均与光合有效辐射、气温、空气相对湿度以及气孔导度4个因子呈极显著相关。     

基于MATLAB的华北落叶松蒸腾仿真模拟

蒸腾是植株主要的耗水形式.以六盘山北侧的华北落叶松为研究对象,采用当前国内外较先进的热扩散式树干边材液流测定技术从单株水平上探讨了华北落叶松的蒸腾速率特性以及其与环境因子之间的影响机理.就气象因子和蒸腾速率进行了分析,提出了气象因子和华北落叶松蒸腾耗水的数学模型.应用Matlab软件对华北落叶松进行了模糊蒸腾模型的设计和仿真.研究结果表明,空气相对湿度和空气温度是影响华北落叶松蒸腾速率的直接因子,太阳辐射式通过改变空气湿度和空气温度进而来影响华北落叶松的燕腾速率.     

黄土丘陵区刺槐蒸腾速率及其环境影响因子

刺槐是一种能在半干旱、半湿润黄土丘陵区良好生长,并具有较高的生态、经济和社会效益的树种。对黄土半湿润区刺槐的蒸腾速率及其影响环境因子,包括饱和水气压差、光量子强度、相对湿度、大气温度等进行测定,得出其在生长季末的蒸腾速率曲线呈单峰型,最高值达1.598mmol／(m2·s);用统计软件MATLAB和SPSS分别对其蒸腾速率和它的影响因子作分析得出,其主要影响因子为光量子强度和饱和水汽压差,这两种软件分析得出结论基本一致。并建立影响因子与蒸腾速率之间的回归方程,其目的是找到刺槐在当地环境条件下作为主要造林树种的依据,为黄土高原植树造林提供理论支持。     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Einfluss der düngungsmethoden auf die entwicklung von zuckerrübenkrankheiten

Während neunjähriger (1994-2002) Untersuchungen in der Versuchsanstalt Ba?cyny (Fahlerde, Fall-Gleyboden, ausgebildet aus leichtem Lehmboden) wurde der Befall mit Krankheiten an der Zuckerrübe in Abhängigkeit von der Düngungsmethode bewertet. Folgende Methoden wurden angewendet: A - Mineraldünger, B - Stalldung und Mineraldünger, C - Stroh-, Gründung und Mineraldünger, D - Kompostdünger und Biopräparate (ökologische Düngung). Auf den Objekten A, B, C wurden bei konstanter Phosphor-Kalium-Düngung die Stickstoffgaben von 0 bis 180 kg.ha^?1 differenziert. Auf dem ökologischen Objekt D ohne Mineraldünger wurden statt Stickstoff die Biopräparate P₅₀₀ und P₅₀₁ verabreicht. Der geringste Befall von Krankheiten wurde an der Zuckerrübe auf jenem Objekt festgestellt, das mit Kompost und den Biopräparaten gedüngt worden war. Im Rahmen der konventionellen Düngungsmethoden wurde allgemein die höchste Intensität der Krankheiten an der mit Stroh, Gründung und Mineraldünger gedüngten Zuckerrübe beobachtet. Ausnahmen von dieser Regel bildete das Vorkommen von echtem Mehltau und Keimlingsfäule. Auf den Objekten A, B, C nahm die Intensität der Krankheiten mit der Steigerung der Stickstoffgabe zu. Auch die auf Objekt D verabreichten Biopräparate stimulierten die Entwicklung der Krankheiten. The effect of various fertilization methods on the diseases of sugar beet was estimated on the basis of nine-year studies (1994-2002) conducted in the Experimental Production Farm in Ba?cyny on loess-based, sedimentary-gley, light-clay soil. The following fertilization methods were applied: A - mineral fertilization, B - mineral and manure fertilization, C - straw, green manure and mineral fertilization, D - ecological compost and biodynamic preparations fertilization. In the objects A, B and C fertilized with phosphorus and potassium, various doses of nitrogen ranging from 0 to 180 kg/ha^?1 were used. In the ecological object D, where mineral fertilization was not used, biodynamic preparations P₅₀₀ and P₅₀₁ were applied instead of nitrogen. The lowest ratio of the diseases of sugar beet was observed in the object fertilized with the compost and biodynamic preparations. In view of the conventional fertilization methods, generally the highest incidence of diseases was noted in the sugar beet fertilized with straw, green manure and mineral fertilizers. The exception was the occurrence of powdery mildew and the black leg. In objects A, B and C the incidence of the diseases increased with the increase in nitrogen doses. The applied biodynamical preparations in the object D stimulated the development of diseases too.     

Prospects for control of Pythium damping-off of lettuce with Trichoderma,Gliocladium and Enterobacter spp.

Summary Damping-off of lettuce (Lactuca sativa) caused by Pythium ultimum was studied in pots containing a non-sterile potting mix in the glasshouse. Fifty P. ultimum sporangia g^-1 compost reduced the plant stand to 15% and shoot dry weight to 18%, but this reduction was totally prevented by applying Trichoderma harzianum at 2×10⁵ viable propagules g^-1 potting mix. Gliocladium virens and Enterobacter cloacae also alleviated the damping-off. E. cloacae did not adversely affect the action of the fungal antagonists. The co-existence of the bacterial and fungal antagonists was revealed on the root surface and inner surface of the testa by scanning electron microscopy, indicating the compatibility of the biocontrol agents.     

细菌、真菌及植物氮营养信号研究进展

氮素吸收代谢是所有生物生命活动的核心部分,因此,各种生物对氮的吸收与同化过程都有精细的调节。这种调节依赖于生物对体内氮素状况信号及体外（生长介质中）氮素信号的感受。过去几十年中,在细菌、真菌中已经对氮素营养信号有了较好的研究,而植物中则相对缓慢,但也有了一定的认识。本文重点比较细菌、真菌及植物中氮信号系统的组成,以期为进一步认识植物中的氮信号接受与转导系统提供启示。     

Aircraft operations near concentrations of birds in Antarctica: The development of practical guidelines

Aircraft operations have the potential to disturb and to impact negatively on bird life. A gradient of increasing behavioural response is evident in birds when exposed to increasing aircraft stimulus. The most major disturbance is likely to lead to impacts on the health, breeding performance and survival of individual birds, and perhaps bird colonies. A process of revision to policies on aircraft operations contained in management plans for a number of specially protected areas in Antarctica by the United Kingdom, accompanied by consultations made within the scientific community through the Scientific Committee on Antarctic Research (SCAR) and with operational interests through the Council of Managers of National Antarctic Programmes (COMNAP) resulted in new guidelines being adopted by the Antarctic Treaty Consultative Parties in June 2004. The principal recommendations of the guidelines are that bird colonies should not be overflown below 2000 ft (∼610 m) above ground level and landings within 1/2 nautical mile (∼930 m) of bird colonies should be avoided wherever possible. These guidelines are less stringent and less specific than those that were recommended by the SCAR specialist group on birds, and represent a compromise to accommodate operational needs. While the adoption of clear and consistent guidelines for the operation of aircraft in Antarctica is welcome in that this provides practical advice that is likely to reduce incidences of close aircraft/bird encounters, there remains insufficient knowledge of the interactions between aircraft and birds in Antarctica, and the consequent impacts on individual birds and on bird populations. It is important, therefore, that the guidelines adopted are considered interim, and should be kept under scrutiny with revisions made as new and improved research results appear.     

The abundance of heterocystous blue-green algae in rice soils and inocula used for application in rice fields

Summary Algal populations were quantified (as colony-forming units [CFU] per square centimetre) in 102 samples of rice soils from the Philippines, India, Malaysia and Portugal, and in 22 samples of soil-based inocula from four countries. Heterocystous blue-green algae (BGA) were present in all samples. Nostoc was the dominant genus in most samples, followed by Anabaena and Calothrix. In soils, heterocystous BGA occurred at densities ranging from 1.0 × 10² to 8.0 × 10⁶ CFU/cm² (median 6.4 × 10⁴) and comprised, on average, 9% of the total CFU of algae. Their abundance was positively correlated with the pH and the available P content of the soils. In soil-based inocula, heterocystous BGA occurred at densities ranging from 4.6 × 10⁴ to 2.8 × 10⁷ CFU/g dw (dry weight), comprising only a moderate fraction (average 13%) of the total algae. In most soils, the density of indigenous N₂-fixing BGA was usually higher than that attained by applying recommended rates of soil-based inoculum. Whereas research on the practical utilization of BGA has been mostly directed towards inoculation with foreign strains, our results suggest that attention should also be given to agricultural practices that enhance the growth of indigenous strains already adapted to local environmental conditions.Maître de Recherches ORSTOM (France), Visiting Scientist at IRRI