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81.
以种植2、4、6、11、13、16、19年的蔬菜日光温室土壤为研究对象,并以露地菜田为对照,测定了土壤微生物区系及酶活性的变化.结果表明: 随着种植年限的增加,土壤中细菌、放线菌和微生物总数均呈现先增加后减少的趋势,在种植11年时达到最大值,分别比对照增加了54.8%、63.7%和55.4%,差异达显著水平;而真菌数量持续上升,种植19年约为对照的2.2倍.微生物生理类群中,纤维素分解菌、自生固氮菌、亚硝酸细菌、反硝化细菌和硫化细菌数量的变化趋势与细菌相似, 种植11年分别为对照的1.5、1.6、1.9、1.4和1.1倍;而氨化细菌数量则呈现先减少后增加的趋势,在种植13年时达到最小值,为对照的56.0%.土壤中脲酶、多酚氧化酶、蔗糖酶、蛋白酶、纤维素酶和碱性磷酸酶活性随种植年限的增加呈现先增强后减弱的趋势,而过氧化氢酶活性较稳定.相关分析表明,细菌、放线菌和微生物总数与各土壤酶均呈显著正相关;而真菌数量与脲酶、蔗糖酶、过氧化氢酶和碱性磷酸酶均呈负相关,其中与过氧化氢酶的相关性达到显著水平. 相似文献
82.
以粉美人萱草(Hemerocallis fulva cv. ‘Fenmeiren’)的花茎为外植体进行离体培养, 该研究成功建立了粉美人萱草组培快繁技术。结果表明, 6月获得的外植体用浓度为15% (v/v)的次氯酸钠溶液消毒8分钟, 外植体存活率达95%; 最佳增殖培养基为MS+1.0 mg·L-1 6-BA+0.004 mg·L-1 TDZ+0.1 mg·L-1 NAA, 培养30天后, 月增殖系数达2.9; 壮苗培养基为MS+0.1 mg·L-1 6-BA+0.1 mg·L-1 IBA, 在该培养基中, 组培苗不再分化, 长势健壮; 最佳生根培养基为1/2MS+0.4 mg·L-1 IBA+20 g·L-1蔗糖, 生根率达95%; 移栽基质采用珍珠岩:草炭=1:2 (v/v), 通过精细化管理, 成活率可达85%, 出圃合格率为75%。目前已实现规模化繁殖, 并生产组培苗2.0×105株, 大田种植表现良好。 相似文献
83.
Emily B. Blackman Christopher S. Deperno Ron W. Heiniger Matthew J. Krachey Christopher E. Moorman M. Nils Peterson 《The Journal of wildlife management》2012,76(3):528-533
Since the late 1960s, American woodcock (Scolopax minor) have undergone population declines because of habitat loss. Previous research suggested ridge and furrow topography in conventionally tilled soybean fields provided critical nocturnal cover as birds foraged on earthworms. However, the use of no-till technology has increased and many fields now lack ridge and furrow topography. We assessed woodcock winter nocturnal foraging habitat use given recent changes in agricultural technology, and investigated how field treatment, earthworm abundance, and environmental variables affect the selection of nocturnal foraging sites. We counted woodcock along transects in 5 field treatments twice in each of 67 fields during December–March 2008–2009 and 72 fields during December–March 2009–2010. During both seasons, we collected earthworm and soil samples from a subset of fields of each field treatment. Woodcock densities were at least twice as high in no-till soybean fields planted after corn and in undisked corn fields with mowed stalks than in other field treatments. No-till soybean planted after corn and undisked corn fields contained ridge and furrow topography, whereas other crops did not, and earthworms were at least 1.5 times more abundant in no-till soybean fields than other field treatments. Ridges and furrows in no-till soybean fields planted after corn and undisked corn fields may provide wintering woodcock with thermal protection and concealment from predators. No-till soybean fields planted after corn offered the additional benefit of relatively high food availability. The presence of ridge and furrow topography can be used to predict woodcock field use on the wintering grounds in agricultural areas. Farmers can provide nocturnal winter foraging sites for woodcock by delaying field disking and leaving ridge and furrow topography in crop fields. © 2011 The Wildlife Society. 相似文献
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85.
基于七叶期开始的夏玉米全生育期不同强度的干旱发生发展模拟试验资料,分析了不同强度的干旱发生发展对夏玉米叶片含水率及光合特性的影响。结果表明:夏玉米生育期内叶片含水率随干旱发生发展呈线性下降趋势,并与土壤相对湿度通过0.005水平的显著性检验,可表征玉米的受旱程度。玉米全生育期内叶片的光合速率、蒸腾速率和气孔导度均随干旱的发生发展呈显著下降趋势,且不同强度干旱的影响差异随时间推移而减小;而叶片水分利用效率则随干旱发生发展呈升高趋势,且随着干旱的发展不同强度干旱间的差异呈增加趋势。玉米全生育期内均出现了光合作用由气孔限制向非气孔限制的转换,转换时间分别为46、38、30和35 d,与干旱强度及持续时间呈反比。 相似文献
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88.
Su Tiing Sai Chan Lai Keng N. Pargini Chris K. H. Teo 《In vitro cellular & developmental biology. Plant》2000,36(5):402-406
Summary An in vitro culture system was developed for Typhonium flagelliforme using buds from the rhizomes. The mineral salts of four media were tested. These were Murashige and Skoog (MS), Nitsch and
Nitsch (NN), Gamborg B5 (GB5) and White (W) of which MS medium was found to be the best medium for in vitro culture of T. flagelliforme. The addition of as low as 0.1 mg l−1 (0.54 μM) α-naphthalene acetic acid (NAA) with the presence or absence of N6-benzyladenine (BA) in the MS medium caused abnormal shoot formation. The best medium for maximizing shoot number combined
with normal complete plantlets from each bud was MS medium supplemented with 0.3 mg l−1 (1.33 μM) BA and 0.5 mg l−1 (2.46 μM) indole-3-butyric acid (IBA). The best acclimatization process was to transfer the normal plantlets, with all the leaves
removed, into sand plus coconut husks substrate (1∶1) and placed in intermittent water mists house or shaded plant house with
50% light exclusion. Ninety two percent of the plantlets survived using this acclimatization method. 相似文献
89.
Mycorrhization helper bacteria (MHBs) isolated and selected from the Douglas fir-Laccaria laccata symbiotic system have previously been shown to be fungus-specific: they promote ectomycorrhizal establishment of Laccaria laccata but inhibit mycorrhiza formation by other fungi. In this paper, two experiments in a nursery producing two years-old bare-root Douglas-fir planting stocks confirm the specificity of MHBs under field conditions. They also show that, by selectively helping the introduced L. laccata against the resident symbionts, MHBs are an interesting alternative (safer and easier) to soil fumigation for the success of routine controlled mycorrhization of planting stocks in forest nurseries. 相似文献
90.
Letícia C. Garcia Richard J. Hobbs Flavio A. Mäes dos Santos Ricardo R. Rodrigues 《Biotropica》2014,46(1):114-123
Frugivores and pollinators are two functional groups of animals that help ensure gene flow of plants among sites in landscapes under restoration and to accelerate restoration processes. Resource availability is postulated to be a key factor to structure animal communities using restoration sites, but it remains poorly studied. We expected that diverse forests with many plant growth forms that have less‐seasonal phenological patterns will provide more resources for animals than forests with fewer plant growth forms and strongly seasonal phenological patterns. We studied forests where original plantings included high tree species diversity. We studied resource provision (richness and abundance of flowers and fruits) of all plant growth forms, in three restoration sites of different ages compared to a reference forest, investigating whether plant phenology changes with restoration process. We recorded phenological data for reproductive plant individuals (351 species) with monthly sampling over 2 years, and found that flower and fruit production have been recovered after one decade of restoration, indicating resource provision for fauna. Our data suggest that a wide range of plant growth forms provides resource complementarities to those of planted tree species. Different flower phenologies between trees and non‐trees seem to be more evident in a forest with high non‐tree species diversity. We recommend examples of ideal species for planting, both at the time of initial planting and post‐planting during enrichment. These management actions can minimize shortage and periods of resource scarcity for frugivorous and nectarivorous fauna, increasing probability of restoring ecological processes and sustainability in restoration sites. 相似文献