钾对龙眼产量和品质的影响

为了提高龙眼产量，提高钾肥的施肥效益，于1993～1995年进行龙眼果园不同钾肥用量的施肥试验．结果表明，龙眼在施用氮碗肥及补充土壤缺乏的中微量元素养分的基础上，增施钾肥可增大果型、提高单果重，显著增加果实产量，并可改善果实品质；龙眼增施钾肥有明显的经济效益．提出龙眼适宜的施钾量为：每株每产50kg鲜果树面年施K2O1.2kg．     

不同形态的肥料对菜心吸收镉的影响

本试验以盆栽方式，设置施不同形态的肥料共10个处理，以菜心为供试作物．测定土壤pH值、菜心产量、菜心植株的含镉量．试验结果表明：（1）10个处理对菜心的产量无显著影响；（2）土壤的pH值与植物的吸镉量呈负相关；土壤的pH值与所施肥料的形态有关，硝态氮肥可以减少植物的吸镉量，铵态氮肥也有一定的效果，硫酸铵则增加植物的吸镉量；磷肥、钾肥效果不显著，不同形态肥料之间的差异未达到显著水平；（3）有机复合肥对减少植物的吸镉量有一定的作用．     

有机肥料对杉木根际土壤生化性质的影响

施用不同有机肥料对杉木幼林根际土壤生物化学性质的影响的研究结果表明，施有机肥料有如下的作用：（１）在很大程度上增加了杉木根际土壤三大类微生物数量．其中以牛栏肥和绿肥混施效果最好，施绿肥又比施牛栏肥效果好，并且施用有机肥料能提高微生物中细菌所占的比例；（２）能增加氨化细菌、硝化细菌、纤维素分解菌和芳香族化合物分解菌的数量，其中氨化细菌提高幅度最大，并以混合施用最好，纤维素分解菌则以单施绿肥最高，芳香族化合物分解菌则以施牛栏肥最高；（３）提高了土壤酶活性，过氧化氢酶、脲酶、磷酸酶和蛋白酶的活性为：混合施用＞施牛栏肥＞施绿肥＞不施肥；（４）不同程度地降低了杉木根际土壤多酚氧化酶的活性．     

萌蘖调控对辽东栎再萌生能力的影响

研究了不同调控措施下辽东栎灌丛再萌生株各生长因子的特征，分析了不同的人为调控措施对辽东栎次生灌丛再萌生能力的影响．结果表明，人为调控对辽东栎再萌生株的发生与生长有着重大影响．调控强度大，再萌生株的数量、高度较小，基径、单株生物量较大；调控强度小，再萌生株的数量、高度较大，基径、单株生物量较小．在辽东栎种群的更新过程中，幼苗与幼树问存在着明显的瓶颈现象，经过激烈的竞争生长，只有少数才能进入下一个生长季．生长季前清除所有再萌生株后，由于当年生长季调控措施的不同，再萌生能力出现差异．调控后，辽东栎灌丛再萌生株的总生物量主要与其高度有关．图2表3参31     

糖厂碳法滤坭对赤红壤上柑桔施用效果初探

试验结果表明，施用碳法滤坭可明显地提高土壤的ｐＨ值和土壤的速效磷含量；适量滤坭配施钾肥可比单施钾肥显著或极显著地提高柑桔的产量，明显地提高柑桔果汁的Ｖｃ和柠檬酸含量，柑桔的可溶性固形物含量、可食部分和果汁含量也有提高；单施滤坭对提高柑桔产量和改善柑桔品质也有一定的效果．滤坭配施钾肥对提高柑桔产质的效果优于与其等当量的石灰配施钾肥，故认为碳法滤坭可代替石灰应用于改良赤红壤的酸性．     

香蕉组培苗的营养和施肥

较系统地研究了香蕉组培苗的营养与施肥，试验方案包括了ＮＰＫ１３种用量水平、１０种不同ＮＰＫ配比和中微量元素混施．试验结果表明，在一定的ＮＰＫ施肥基础上．再增施ＮＰＫ均能获得不同程度的增产，其中增施Ｎ的增产幅为４．７％－１５．０％，增施Ｐ、Ｋ的分别为３．４％－１５．１％和６．６％－１２．６％．增Ｎ有利于植株增高、茎围增粗、长叶增快和提早吐蕾；增Ｐ对植株增高和提早吐蕾也有一定的作用；增Ｋ主要有利于茎围增粗，但在高Ｎ高Ｐ下增Ｋ也同样具有增Ｎ的多种效果．增Ｋ的另一效应是延缓吐蕾期而使吐蕾期较集中一致，这有利于田间管理和收获；施用中微量元素的增产效果显著，同时也改善和提高了果实品质．应提倡应用和推广．     

不同硫肥品种的水稻肥效试验研究

在缺硫土壤上以石膏、硫磺、硫酸钾镁（SPM）作为流源进行硫肥水稻试验，并设置与石膏等钙量、与SPM等镁量的石灰、MgCl3处理，结果显示，增施硫、钙、镁，水稻均有显著增产，其中硫的增产效果最好；在3个硫肥品种中，以施石膏增产最大、施硫磺效益最佳。讨论了施硫对水稻生长发育、营养状况及对稻谷品质的影响。     

水分胁迫对燥红土和变性土上生长的玉米叶片几种酶活性的影响

采用盆栽控制试验，研究了不同处理条件下，水分胁迫对金沙江干热河谷典型土壤(燥红土和变性土)生长的玉米(Zea mays L.)叶片中几种酶活性的影响．结果表明：(1)在一定的水分胁迫范围内，玉米叶片的过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(ASP)和多酚氧化酶(PPO)活性均随着土壤含水量的降低而升高，但过度胁迫时，酶活性降低；(2)随着土壤含水量降低，玉米叶片中保护酶活性的变化规律略有差异，这与二者的土壤物理性质有关；(3)施肥处理和栽培方式对玉米叶片的酶活性有影响，增施有机肥和Zn肥可提高适度水分亏缺条件下玉米叶片中POD、CAT、ASP和PPO活性．图4参35     

施肥对不同农田土壤微生物活性的影响

采用室内恒温培养研究了施肥对不同农田土壤微生物活性的影响。结果表明，在红壤、水稻土和潮土中，土壤微生物量、土壤酶活性大小顺序均为有机肥配施无机肥处理＞单施有机肥处理＞单施无机肥处理，但对脲酶来说，其活性大小顺序为有机肥配施无机肥处理＞单施无机肥处理＞单施有机肥处理。从土壤类型来看，土壤微生物量碳、氮和土壤酶活性大小以水稻土最大，潮土次之，红壤最小。３种土壤的微生物量、土壤酶活性在培养的４５～６０ｄ之间分别达到最大值，以后逐渐下降。部分单施无机肥处理的土壤微生物量、土壤酶活性最大值比单施有机肥处理、有机肥配施无机肥处理提前１５ｄ。相关分析表明，有机肥配施无机肥处理及单施有机肥处理，３种土壤的土壤微生物量碳、氮与土壤过氧化氢酶、转化酶、蛋白酶、脲酶及速效养分呈显著或极显著的相关性；单施无机肥处理中，土壤微生物量碳、氮与土壤过氧化氢酶、蔗糖转化酶、蛋白酶、脲酶显著或极显著相关，与部分速效养分相关不显著。     

酸性土壤改良对不同种源的柚木生长的影响

在强酸性土壤上，柚木不能正常生长；用石灰、有机肥和复合肥改良土壤后．树木生长正常，但如不继续追肥．生长将显著下降；7794、8508号种源的柚木在改良后的土壤上生长最好；7794．8508和3054号种源的柚木表现出对酸性土壤有一定的抗性；来自同一种源的个体之间存在着显著的生长差异．     

The reproductive cycle of the Thecosomatous pteropod Limacina retroversa in the western South Atlantic

The reproductive cycle of Limacina retroversa in the Argentine Sea was studied by gonadal analysis. Samples were collected in 1978–1979. The relation between gonadal maturity and size is dependent on the season and the geographical area. Evidence of in situ reproduction was found at the beginning of spring and at the end of summer, indicating that the life cycle in the area consists of two generations per year. In accordance with the season of birth, both generations develop different strategies. Individuals born in spring mature early and reproduce before the end of summer. The offspring born in summer survive the cold season without reaching sexual maturity and reproduce in the following spring.     

Production dynamics of the eelgrass, <Emphasis Type="Italic">Zostera marina</Emphasis> in two bay systems on the south coast of the Korean peninsula

Production dynamics of eelgrass, Zostera marina was examined in two bay systems (Koje Bay and Kosung Bay) on the south coast of the Korean peninsula, where few seagrass studies have been conducted. Dramatically reduced eelgrass biomass and growth have been observed during summer period on the coast of Korea, and we hypothesized that the summer growth reduction is due to increased water temperature and/or reduced light and nutrient availabilities. Shoot density, biomass, morphological characteristics, leaf productivities, and tissue nutrient content of eelgrass were measured monthly from June 2001 to April 2003. Water column and sediment nutrient concentrations were also measured monthly, and water temperature and underwater irradiance were monitored continuously at seagrass canopy level. Eelgrass shoot density, biomass, and leaf productivities exhibited clear seasonal variations, which were strongly correlated with water temperature. Optimal water temperature for eelgrass growth in the present study sites was about 15–20°C during spring period, and eelgrass growths were inhibited at the water temperature above 20°C during summer. Daily maximum underwater photon flux density in the study sites was usually much higher than the light saturation point of Z. marina previously reported. Densities of each terminal, lateral, and reproductive shoot showed their unique seasonal peak. Seasonal trends of shoot densities suggest that new eelgrass shoots were created through formation of lateral shoots during spring and a part of the vegetative shoots was transformed into flowering shoots from March. Senescent reproductive shoots were detached around June, and contributed to reductions of shoot density and biomass during summer period. Ambient nutrient level appeared to provide an adequate reserve of nutrient for eelgrass growth throughout the experimental period. The relationships between eelgrass growth and water temperature suggested that rapid reductions of eelgrass biomass and growth during summer period on the south coast of the Korean peninsula were caused by high temperature inhibition effects on eelgrass growth during this season.     

Ranking of individual mountain birch trees in terms of leaf chemistry: seasonal and annual variation

Summary. The quality of tree leaves as food for herbivores changes rapidly especially during the spring and early summer. However, whether the quality of an individual tree in relation to other trees in the population changes during the growing season and between years is less clear. We studied the seasonal and annual stability of chemical and physical traits affecting leaf quality for herbivores. Rankings of trees in terms of the contents of two major groups of phenolics in their leaves, hydrolyzable tannins and proanthocyanidins (condensed tannins), were very stable from the early spring to the end of the growing season. There were also strong positive within-season correlations in the levels of some other groups of phenolics in the leaves (kaempferol glycosides, myricetin glycosides and p-coumaroylquinic acid derivatives). The contents of individual sugars and the sum content of protein-bound amino acids showed patterns of seasonal consistency in mature leaves, but not in young developing leaves. The seasonal correlations in leaf water content and toughness were also strongest in mature leaves. The correlations between two years at corresponding times of the growing season were strongly positive for the major groups of phenolics throughout the season, but were more variable for the contents of proteins and some sugars. Leaf toughness and water content showed strong positive correlations in mature leaves. Despite the consistency of tree ranking in terms of leaf phenolics, the relative resistance status of trees may, however, change during a growing season because there was a negative correlation between the content of hydrolyzable tannins (early-season resistance compounds) in leaves early in the season and the content of proanthocyanidins (late-season resistance compounds) late in the season, and vice versa. Thus, assuming that phenolics affect herbivore preference and performance, different plants may suffer damage at different times of the growing season, and the overall variation between trees in the fitness consequences may be low. In addition, the adaptation of herbivorous insects to mountain birch foliage in general, as well as to specific tree individuals, may be constrained by variation in the relative resistance status of the trees.     

Physiological benefits of feeding in the spring by Lymantria dispar caterpillars on red oak and sugar maple leaves: nutrition versus oxidative stress

The rapid growth of insects that feed on tree leaves in the spring is believed to be due to high nutritional quality. This study tested the hypothesis that both high nutritional quality and low levels of oxidative stress (i.e., toxicological effects) benefit caterpillars that feed in the spring. Fourth-instar larvae of Lymantria dispar (Lepidoptera: Lymantriidae) were used to bioassay the leaves of two contrasting host plants in the spring and summer: red oak (Quercus rubra), a high-quality host, and sugar maple (Acer saccharum), a low-quality host. On spring foliage, the combined effects of rapid consumption rate, efficient nutrient assimilation, and high nutritional quality allowed larvae to grow rapidly and attain larger body mass. Ellagitannins, a major source of oxidative stress in the midgut, were at higher concentrations in the spring than in the summer in maple leaves, but were at negligible levels throughout the growing season in oak. Thus, the impact of phenolic defenses (measured as semiquinone free radicals and oxidized glutathione in the midgut) was not decreased in spring-feeding larvae. Instead, oxidative stress in larvae on maple remained at elevated levels in the spring and summer. By contrast, larvae that fed on oak had consistently low levels of oxidative stress. We conclude that oak and maple were better host plants in the spring because of their higher nutritional quality, and not because of a lower effectiveness of their chemical defenses. This work emphasizes the need to measure not only foliar nutritional and phenolic chemistry but also specific physiological responses in the herbivore, such as oxidative stress. These physiological mechanisms add to our understanding of why spring-feeding life-history strategies have evolved in some insect herbivores.     

Gonadal cycle in an<Emphasis Type="Italic"> Adelomelon brasiliana</Emphasis> (Neogastropoda: Volutidae) population of Buenos Aires province,Argentina

The reproductive season of the Adelomelon brasiliana population of Mar del Plata extends from September to April (austral spring and summer), showing synchronisation with water temperature. Adult gonad state is related to shell-free wet mass. Oocytes reach 200 m in diameter before spawning. In autumn, a resting phase begins, when no new oocytes develop and the non-spawned ones undergo reabsorption. Gonadic development begins during the early winter, when new previtellogenic oocytes can be observed through histology. The long reproductive season would increase the ability of the species to recover from harvesting.Communicated by O. Kinne, Oldendorf/Luhe     

Linkages between phenology, pollination, photosynthesis, and reproduction in deciduous forest understory plants

Light availability in the understory of deciduous forests changes drastically within the growing season due to the foliage dynamics of canopy trees. Because flowering phenology, photosynthetic characteristics, and fruiting success respond to such strong seasonality in light availability, we hypothesized that understory plants in such ecosystems should describe distinct phenological groups or syndromes where "syndrome" is defined only as a set of characteristics that co-occur. To identify these phenological syndromes, we studied the flowering phenology, fruit or seed set, and photosynthetic characteristics for 18 perennial understory herbaceous species that differed in reproductive strategy over eight years in a deciduous forest in northern Japan. Three phenological groups emerged from this study: (1) spring bloomers, flowering and fruiting before the completion of canopy closure; (2) early-summer bloomers, flowering during the progress of canopy closure and fruiting after canopy closure; and (3) late-summer bloomers, flowering and fruiting after canopy closure. The spring bloomers had high photosynthetic rates and high fruiting abilities, but the flowering time varied considerably among years due to yearly fluctuations of snowmelt date. Bumble bee-pollinated species of spring bloomers showed variable seed-set success, while fly-pollinated species showed relatively stable seed sets over the years. The early-summer bloomers showed low fruiting abilities irrespective of pollination success, reflecting severe resource limitation with decelerating light availability during fruit development. Although the late-summer bloomers showed low photosynthetic rates under low-light conditions, high fruit-set success was attained if pollination was sufficient. These results support our hypothesis that phenological syndromes may be found in deciduous forest understory plants. Given that reproductive success of bee-pollinated spring bloomers is highly susceptible to seasonal fluctuation, climate change may have its strongest impacts on this group.     

Soil nutrient supply modulates temperature-induction cues in mast-seeding grasses

Synchronous and intermittent reproduction in long-lived plants, known as mast seeding, is induced by climatic cues, but the mechanism explaining variation in masting among neighboring but edaphically segregated species is unknown. Soil nutrients can enhance flowering, and thus, populations on nutrient-rich soils may require less-favorable growing temperatures to flower. We tested this hypothesis by predicting the probability of flowering in response to air temperature for five species of alpine Chionochloa grasses in South Island, New Zealand, over 37 years and relating our predictions to soil N supply (NH4(+) + NO3(-)). Summer air temperatures better predicted flowering than spring air temperatures, which were correlated with soil N mineralization. Species on N-rich soils required lower mean temperatures to induce flowering and/or responded more consistently across a gradient of air temperatures, contributing to the higher probability of their tillers and tussocks flowering at low summer temperatures. Our results suggest that flowering primarily occurs in response to warm summer temperatures, but species on N-rich soils require less favorable growing conditions because they invest relatively less N in seeds. Thus, predicting masting requires a consideration of the interactions among climate, the internal resources of plants, and mineral nutrient uptake.     

桔园间作牧草的生态效益及其管理技术

在浙江省金华地区新垦植的红壤幼龄桔园及盛产成龄桔园进行了间作试验和调查研究。结果表明，幼龄桔园间作黑麦草或紫云英，能提高光能利用率，具有延缓秋冬土壤降温和春季土壤升温、减小土壤日温差幅度和冬季保暖、降低水土流失量等生态效应，但对夏梢生长具有不良的影响；成龄桔园长期间作紫云英也具有提高光能利用率，维持较高的肥料养分效率，明显改善土壤肥力，提高产量和改善柑桔外观品质等多种效益。桔园间作牧草应结合柑桔生产的要求，抓住适时拌肥播种、及时收割施肥和适时适量归还土壤３个管理技术要点。     

基于GIS的中国API指数时空分布规律研究

以2009年1月至2012年12月的中国120个重点城市的API监测数据为基础,通过选取最优的空间插值方法获得各月及各季节的API空间分布图,并运用剖面线分析等空间数据分析方法研究其空间分布规律。结果表明,API在不同时段的变化较大;存在着明显的季节变化趋势,总体上冬季最高、春季次之、夏季最低,且夏秋季基本均分布在100以内;中国空气质量状况总体良好,API主要分布在51~100之间,但有较多地区分布在80~100间,空气环境质量仍不容乐观;API分布着以兰州和西宁为中心、陕西省西安市为中心及乌鲁木齐市和吐鲁番市为中心的几个空气质量较差的高值集聚的＂热点＂区域及海南省、广东省及福建省的沿海区域、西藏自治区等几个空气质量较好的低值集聚的＂冷点＂区域;在N-S、WE、NW-SE、NE-SW四个剖面线方向上相同季节的分布趋势基本一致,且同一方向上春夏秋冬四季的分布也大致相同,基本呈现＂低-高-低＂的分布趋势且北方地区明显高于南方地区。