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1.
60年来我国落叶果树叶螨的种群演变反映了果树害虫防治体系的变迁,从而窥见我国果树病虫害防治技术的进步。果树叶螨种群的变化与果园病虫害防治方法及药剂种类的变化有明显的相关性,建议果园管理者一定要合理使用化学农药,积极使用生物农药、植物源农药及矿物源农药,促进果树生产健康、可持续地发展。 相似文献
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Kiwifruit (Actinidia deliciosa (Chev.) Liang and Ferguson) is a dioecious species highly pollination dependent, since fruit size is directly correlated with seed number. To evaluate the best pollination system for this species a study of two natural and two artificial pollination systems was carried out and their effect on fruit set and fruit quality was determined. While anemophilous pollination produced few and small fruits, that were not commercially acceptable, high fruit set percentages and good quality fruits were obtained when insects participated in the pollination process. Artificial pollination, performed as hand pollination, improved yield quantity and quality. When environmental conditions impair insect activity this method can be an useful agricultural practice in order to assure a good yield. 相似文献
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Wolfgang Wilms Lutz Wendel Anne Zillikens Betina Blochtein Wolf Engels 《Studies on Neotropical Fauna and Environment》2013,48(4):220-226
Flower visiting insects were monitored on angiosperm trees in an Araucaria forest in Rio Grande do Sul, Brazil. The most abundant flower visitors were workers of the introduced honey bee, Apis mellifera, followed by stingless bees which were represented by 8 species. Together with other bees, they provide the main guild of foragers on flowering trees. The stingless bee fauna of the study area is similar to that of other regions of the Mata Atlântica, especially of former Araucaria forests, but also of montane coastal rain forests. 相似文献
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Douglas Sponsler;Christophe Dominik;Carolin Biegerl;Hanna Honchar;Oliver Schweiger;Ingolf Steffan-Dewenter; 《Oikos》2024,2024(9):e10495
Competition among pollinators for floral resources is a phenomenon of both basic and applied importance. While competition is difficult to measure directly under field conditions, it can be inferred indirectly through the measurement of floral resource depletion. In this study, we conducted a pollinator exclusion experiment to calculate nectar depletion rates in summer across 16 grassland sites in the German regions of Franconia and Saxony-Anhalt. Overall depletion rates were estimated at 95% in Franconia and 79% in Saxony-Anhalt, indicating strong nectar limitation and likely competition among pollinators for nectar. Despite being ubiquitous in our study regions, honey bees were scarce at our sites at the time of nectar sampling. This demonstrates that wild pollinators alone are capable of massive nectar depletion, and the addition of managed honey bees to wild pollinator communities may intensify already competitive conditions. Nevertheless, the manifest diversity of the pollinator communities at our sites indicates that other factors, such as non-trophic constraints or temporal variation in nectar limitation, can mitigate competitive exclusion despite immediate conditions of acute nectar scarcity. 相似文献
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RAPD技术在果树种质资源研究中的应用（综述） 总被引：4，自引：0，他引：4
PAPD技术具有快速、方便、灵敏度高、检测容易的优点,在颗树种质资源及育种中应用潜力颇大。本文综述为RAPD技术在颗树种质资源中的应用状况。 相似文献
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We measured rates of leaf senescence and leaf level gas exchange during autumnal senescence for seedlings of five temperate forest tree species under current and elevated atmospheric CO2 concentrations and low- and high-nutrient regimes. Relative indices of whole canopy carbon gain, water loss and water use efficiency through the senescent period were calculated based on a simple integrative model combining gas exchange per unit leaf area and standing canopy area per unit time. Seedlings grown under elevated [CO2] generally had smaller canopies than their current [CO2]-grown counterparts throughout most of the senescent period. This was a result of smaller pre-senescent canopies or accelerated rates of leaf drop. Leaf-level photosynthetic rates were higher under elevated [CO2] for grey birch canopies and for low-nutrient red maple and high-nutrient ash canopies, but declined rapidly to values below those of their current [CO2] counterparts by midway through the senescent period. CO2 enrichment reduced photosynthetic rates for the remaining species throughout some or all of the senescent period. As a result of smaller canopy sizes and reduced photosynthetic rates, elevated [CO2]-grown seedlings had lower indices of whole canopy end-of-season carbon gain with few exceptions. Leaf level transpiration rates were highly variable during autumnal senescence and neither [CO2] nor nutrient regime had consistent effects on water loss per unit leaf area or integrated whole canopy water loss throughout the senescent period. Indices of whole canopy, end-of-season estimates of water use efficiency, however, were consistently lower under CO2 enrichment, with few exceptions. These results suggest that whole canopy end-of-season gas exchange may be altered significantly in an elevated [CO2] world, resulting in reduced carbon gain and water use efficiency for many temperate forest tree seedlings. Seedling growth and survivorship, and ultimately temperate forest regeneration, could be reduced in CO2-enriched forests of the future. 相似文献
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We examined the phytopathological and biological characters ofBotryosphaeria spp. isolated from apples and other deciduous fruit trees, and determined the nucleotide sequences of their rDNA ITS regions. TheBotryosphaeria isolates from deciduous fruit trees can be divided into three groups based on their production of warts on twigs, size of the conidia, and nucleotide sequences of rDNA ITS 1, ITS 2 and 5.8S rDNA. Isolates ofBotryosphaeria in ITS group A produced conidia of intermediate size and showed warts on infected twigs prior to the development of ring rot on fruit. This group was common on deciduous fruit trees in Japan as a causal agent of ring rot and wart bark diseases of apples and pears; and it appears similar to theB. dothidea from the US that was isolated from apple exhibiting white rot. The ITS group BBotryosphaeria produced small conidia and induced shoot blight without wart development prior to the development of ring rot on fruit. This group was localized on pear, persimmon, and kiwi fruit in restricted areas of Japan. The ITS group CBotryosphaeria consisted ofB. obtusa, the causal agent of apple black rot in the US, which produced large dark brown conidia. 相似文献
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Lise Ropars;Laurence Affre;Élisa Thébault;Benoît Geslin; 《Oikos》2022,2022(4):e08915
Due to the widespread use of pesticides and the lack of floral resources in many agricultural landscapes, beekeepers have moved numerous honey bee colonies in protected areas which could shelter an important diversity of wild bees. Here, we investigated the seasonal dynamics of the competition between honey bees and wild bees through a two-year study of plant–bee networks in a Mediterranean protected area. We recorded the visitation rates of four bee groups: honey bees, small wild bees, large wild bees and bumblebees. Our study reveals that the competition for floral resources induced by honey bees is especially strong during the early spring and then decreases along the season for all groups of wild bees. We observed a competitive exclusion of all groups of wild bees illustrated by an avoidance of well-flowered plant species in presence of honey bees. As a consequence, we detected a rewiring of large and small bee floral preferences linked to the presence of honey bees. In presence of honey bees, Rosmarinus officinalis and Cistus albidus were significantly less visited by large bees. This study underlines the need to mitigate the establishment of numerous honey bee colonies in protected areas as honey bees could strongly affect the foraging activity of wild bees. 相似文献
9.
A comparison was made of energy metabolism of nodulated N2 fixing plants and non-nodulated NO3-fed plants of Lupinus albus L. Growth, N-increment, root respiration (O2 uptake and CO2 production) and the contribution of a SHAM-sensitive oxidative pathway (the alternative pathway) in root respiration were measured. Both growth rate and the rate of N-increment were the same in both series of plants. The rate of root respiration, both O2 uptake and CO2 production, and the activity of the SHAM-sensitive pathway were higher in NO3-fed plants than in N2 fixing plants. The rate of ATP production in oxidative phosphorylation was computed also to be higher in NO3-fed plants. It is concluded that both carbohydrate costings and ATP costings for synthesis + maintenance of root material were lower in N2 fixing than in NO3-fed plants. The respiratory quotient of root respiration was 1.6 in N2-fixing plants and 1.4 in NO3-fed plants. These values were slightly higher than the values calculated on the basis of CO2 output due to N-assimilation and the experimental values of O2 uptake, but showed the same trend: highest in N2 fixing plants. Root respiration of NO3-fed plants showed a diurnal pattern (both O2 uptake, CO2 production and the activity of the SHAM-sensitive pathway), whilst no diurnal variation in root respiration was found in N2 fixing plants. However, C2H2 reduction did show a diurnal rhythm, which is suggested to be related to the diurnal variation in transpiration. Addition of NO3 to N2 fixing plants increased the rate of root respiration and the activity of the alternative pathway. This treatment did not decrease C2H2 reduction and H2 evolution within 4 days. Withdrawal of NO3-supply from NO3-fed plants decreased the rate of root respiration but had no effect on the relative activity of the alternative pathway. It is suggested that the higher rate of root respiration and the higher activity of the SHAM-sensitive pathway in NO3-fed plants is due to a larger supply of carbohydrates to the roots, partly due to a better photosynthetic performance of the shoots and partly due to a higher capacity of the roots to attract carbohydrates. 相似文献
10.
Abstract In many previous studies of the effects of introduced honeybees on Australian ecosystems, it has been assumed that floral morphology is a primary factor determining whether introduced honeybees will be effective in pollinating endemic plants. Although both honeybees and birds contacted stigmas and anthers of the small‐flowered Brachyloma ericoides (Epacridaceae), the exclusion of birds but not honeybees resulted in a significantly lower proportion of flowers producing capsules (12.3 ± 2 vs 21.0 ± 2%). This suggests that native birds contributed significantly to fruit set even though honeybees were much more frequent visitors to flowers (5–6 vs 0.7–2.5 times per day) and moved more frequently between plants (25 vs 12.2% of movements). Fruit set following exposure to birds and honeybees was very low compared with shrub species in general and may have been limited by the pre‐emptive removal of pollen by the 10% of honeybees that actively collected pollen. 相似文献
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Winter photosynthesis by saplings of evergreen broad-leaved trees in a deciduous temperate forest 总被引：3，自引：0，他引：3
* Here we investigated photosynthetic traits of evergreen species under a deciduous canopy in a temperate forest and revealed the importance of CO2 assimilation during winter for annual CO2 assimilation. * Saplings were shaded by the canopy trees from spring through to autumn, but were less shaded during the winter months. Photosynthetic rates at light saturation (Aarea) were lower during winter than during the growing season. Aarea was higher in Camellia, Ilex and Photinia than in Castanopsis, Cleyera and Quercus during the winter, but differed little during summer and autumn. * Estimated daily CO2 assimilation (Aday) was higher during the winter than during the growing season in Camellia, Ilex and Photinia but was higher than that during the growing season only at the beginning and end of winter in Castanopsis, Cleyera and Quercus. Aday was higher in Camellia, Ilex and Photinia than in Castanopsis, Cleyera and Quercus but differed little among them during the growing season. * These results reveal the importance of winter CO2 assimilation for the growth of Camellia, Ilex and Photinia. Furthermore, differences in annual CO2 assimilation among species are strongly modified by species-specific photosynthetic traits during the winter under deciduous canopy trees. 相似文献
13.
Lucia R. Weinman Trent Ress Joel Gardner Rachael Winfree 《American journal of botany》2023,110(6):e16178
Premise
Bees provision most of the pollen removed from anthers to their larvae and transport only a small proportion to stigmas, which can negatively affect plant fitness. Though most bee species collect pollen from multiple plant species, we know little about how the efficiency of bees' pollen transport varies among host plant species or how it relates to other aspects of generalist bee foraging behavior that benefit plant fitness, such as specialization on individual foraging bouts.Methods
We compared the pollen collected and transported by three bee species for 46 co-occurring plant species. Specifically, we compared the relative abundance of pollen taxa in the individual bees' scopae, structures where bees store pollen to provision larvae, with the relative abundance of pollen taxa on the rest of bees' bodies, which is more likely to be transferred to stigmas.Results
Bees carried five times more pollen grains in their scopae than elsewhere on their bodies. Within foraging bouts, bees were relatively specialized in their pollen collection, but transported proportionally less pollen for the host plants on which they specialized. Across foraging bouts, two bee species transported proportionally less pollen for some of their host plants than for others, though differences didn't consistently follow the same trend as at the foraging bout scale.Conclusions
Our results suggest that foraging-bout specialization, which is known to reduce heterospecific pollen transfer, also results in less-efficient pollen transport. Thus, bee foragers that visit predominantly one plant species may have contrasting effects on that plant's fitness.14.
Patrick Schleppi Inga Bucher‐Wallin Frank Hagedorn Christian Körner 《Global Change Biology》2012,18(2):757-768
In a mature temperate forest in Hofstetten, Switzerland, deciduous tree canopies were subjected to a free‐air CO2 enrichment (FACE) for a period of 8 years. The effect of this treatment on the availability of nitrogen (N) in the soil was assessed along three transects across the experimental area, one under Fagus sylvatica, one under Quercus robur and Q. petraea and one under Carpinus betulus. Nitrate, ammonium and dissolved organic N (DON) were analysed in soil solution obtained with suction cups. Nitrate and ammonium were also captured in buried ion‐exchange resin bags. These parameters were related to the local intensity of the FACE treatment as measured from the 13C depletion of dissolved inorganic carbon in the soil solution. Over the 8 years of experiment, the CO2 enrichment reduced DON concentrations, did not affect ammonium, but induced higher nitrate concentrations, both in soil solution and resin bags. In the nitrate captured in the resin bags, the natural abundance of the isotope 15N increased strongly. This indicates that the CO2 enrichment accelerated net nitrification, probably as an effect of the higher soil moisture resulting from the reduced transpiration of the CO2‐enriched trees. It is also possible that N mineralization was enhanced by root exudates (priming effect) or that the uptake of inorganic N by these trees decreased slightly as the result of a reduced N demand for fine‐root growth. In this mature deciduous forest, we did not observe any progressive N limitation due to elevated atmospheric CO2 concentrations; on the contrary, we observed an enhanced N availability over the 8 years of our measurements. This may, together with the global warming projected, exacerbate problems related to N saturation and nitrate leaching, although it is uncertain how long the observed trends will last in the future. 相似文献
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Jep Agrell Brian Kopper† Evan P. McDonald‡ Richard L. Lindroth§ 《Global Change Biology》2005,11(4):588-599
Elevated levels of CO2 and O3 affect plant growth and phytochemistry, which in turn can alter physiological performance of associated herbivores. Little is known, however, about how generalist insect herbivores respond behaviorally to CO2‐ and O3‐mediated changes in their host plants. This research examined the effects of elevated CO2 and O3 levels on host plant preferences and consumption of forest tent caterpillar (FTC, Malacosoma disstria Hbn.) larvae. Dual choice feeding assays were performed with foliage from birch (Betula papyrifera Marsh.) and aspen (Populus tremuloides Michx., genotypes 216 and 259). Trees were grown at the Aspen Free Air CO2 Enrichment (FACE) facility near Rhinelander, WI, USA, and had been exposed to ambient or elevated concentrations of CO2 and/or O3. Levels of nutritional and secondary compounds were quantified through phytochemical analyses. The results showed that elevated O3 levels increased FTC larval preferences for birch compared with aspen, whereas elevated CO2 levels had the opposite effect. In assays with the two aspen genotypes, addition of both CO2 and O3 caused a shift in feeding preferences from genotype 259 to genotype 216. Consumption was unaffected by experimental treatments in assays comparing aspen and birch, but were increased for larvae given high O3 foliage in the aspen genotype assays. Elevated levels of CO2 and O3 altered tree phytochemistry, but did not explain shifts in feeding preferences. The results demonstrate that increased levels of CO2 and O3 can alter insect host plant preferences both between and within tree species. Also, consequences of altered host quality (e.g., compensatory consumption) may be buffered by partial host shifts in situations when alternative plant species are available. Environmentally induced changes in host plant preferences may have the potential to alter the distribution of herbivory across plant genotypes and species, as well as competitive interactions among them. 相似文献
17.
Takayoshi Koike Hiroyuki Tobita Takanori Shibata Sawako Matsuki Kotaro Konno Mitsutoshi Kitao Naoko Yamashita Yutaka Maruyama 《Population Ecology》2006,48(1):23-29
Mixed broad-leaved forests are abundantly populated by several kinds of herbivore species in northern Japan. The life of herbivores depends strongly on the quality of food leaves. Leaf quality is changing with increasing atmospheric CO2 and nitrogen deposition. Four seral species of deciduous broad-leaved tree seedlings (alder, birch, oak and maple) were raised in all four combinations of two levels of CO2 and two levels of nutrient, to examine foliar defense traits. To evaluate the relative defense capacity of the four tree species, we used wild silkworms (Erisan; a generalist herbivore) as a bioassay material. Except with alder, the survival rate and longevity (ML50) of the silkworms were least when they were fed with leaves of seedlings raised under high CO2 and infertile soil conditions, and longest on a diet of leaves grown in ambient CO2 and fertile soil, especially in birch and maple. The longevity of Erisan decreased in the order birch, oak, and maple. The longevity of Erisan fed with alder leaves was independent of CO2 levels and was longer on alder seedlings grown in infertile soil conditions. Alder is an actinorhizal plant that can fix atmospheric nitrogen in root nodules formed by the actinomycetes Frankia sp. The activity of symbiotic microbes would have been enhanced by the greater amount of photosynthates received from the host plants at high CO2, improving the food quality for the silkworms. It was concluded that in all but alder, leaf chemical traits, especially C/N ratio, affect the ML50 of Erisan larvae. 相似文献
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