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1.
不同种源白刺幼苗生理生长对水分梯度的响应差异 总被引：3，自引：0，他引：3
在乌兰布和沙漠东北部地区,依据多年平均月降水量,对5个种源的白刺幼苗进行极度干旱、干旱、轻度干旱和正常降雨水平4种不同的水分梯度处理,开展水分梯度试验.通过测定不同水分梯度、不同种源的光合生理指标表明:水分梯度显著影响白刺幼苗的净光合速率、蒸腾速率、气孔限制值、气孔导度、光合水分利用效率、表观光能利用效率、表观CO2利用效率等生理生态特征,并影响植株的苗高和最大新枝长等生长量指标;不同种源之间的净光合速率、水分利用效率、表观光能利用效率、表观CO2利用效率存在显著差异,且在苗高和最大新枝长之间也存在显著差异,但不同种源、不同水分梯度对幼苗的地径均无显著影响.相比于临河、乌拉特后旗种源,磴口、阿拉善盟和民勤种源的蒸腾速率和资源利用效率在不同水分处理之间表现出显著差异,且3个种源的各个资源利用效率都较大.白刺幼苗在光合活动中的气体交换及资源利用效率的生理反应和外在的生长量表型指标的差异,反映了各白刺种源对不同水分环境表现出的响应差异. 相似文献
2.
以该区年龄相同的5种主要植被恢复树种车桑子、滇柏、侧柏、花椒和香樟幼苗为研究对象,通过盆栽控水试验,测算其在不同水分梯度下的叶绿素相对含量、净光合速率、蒸腾速率、气孔导度、胞间CO2浓度以及水分利用效率等生理生态指标,系统比较各参数的适应性变化及其差异性分析,结果表明：（1）随着干旱胁迫的加剧,5种幼苗叶片叶绿素相对含量呈现不同的变化趋势,车桑子逐渐降低,侧柏和滇柏先降后升,花椒和香樟先升后降;（2）各光合生理生态参数也呈现不同的变化规律：随干旱胁迫的加剧,净光合速率、蒸腾速率、气孔导度均逐渐降低,且在中度和重度干旱胁迫时极显著降低,其中在重度干旱胁迫时,侧柏的净光合速率最低比对照下降了100.5%,下降幅度最大;胞间CO2浓度在轻度干旱胁迫时下降,中度和重度干旱胁迫时上升;水分利用效率在轻度和中度干旱胁迫时增加,重度干旱胁迫时下降,其中香樟的水分利用效率在重度干旱胁迫时仍是对照的1.05倍;（3）综合分析各项生理生态参数,5种幼苗均能耐受一定程度的干旱胁迫,但香樟的控水耐旱能力明显高于其它4种树种,更能适应石漠化地区的生态环境。 相似文献
3.
采用完全随机区组试验设计,研究了不同种源台湾桤木(Alnus formosana)光合及生长特征的月动态变化,为台湾桤木优良种源的选择提供理论依据。结果表明:不同月份、不同种源间台湾桤木光合生理特性差异显著,净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)及水分利用效率(WUE)表现出对气候变化的适应,均随月份的变化而变化。各种源台湾桤木净光合速率、气孔导度和水分利用效率在8—10月份均较低,4月份和12月份较高。蒸腾速率8月份最高,4月份和12月份较低。相关分析表明:苗高与地径表现了显著的正相关,P_n与G_s、WUE表现了显著正相关,G_s与WUE表现了显著正相关,而T_r与G_s、WUE均表现了显著的负相关。在南宁地区引种,建议优先选择具有高生物量的四川和湖南种源。 相似文献
4.
干旱胁迫对蚬木幼苗生长及光合特征的影响 总被引：1，自引：0，他引：1
为探讨蚬木(Excentrodendron hsienmu)幼苗对干旱的适应能力,采用盆栽水分胁迫试验法,比较了田间最大持水量的65%~75%(对照)、50%~60%(轻度胁迫)、35%~45%(中度胁迫)和20%~30%(重度胁迫)4个水分梯度下,蚬木幼苗的生长、生物量分配及光合参数的变化。结果显示,重度胁迫显著抑制了幼苗的株高生长,地径生长受干旱影响不明显;中度和重度胁迫对植株茎、叶及总生物量积累产生显著影响,地上生物量比随土壤干旱增强下降、根生物量比和根冠比增加。干旱胁迫显著降低蚬木幼苗叶片的净光合速率、蒸腾速率和气孔导度。胞间CO2浓度在干旱初期先降后升、气孔限制值逐渐增加;随干旱时间延长和胁迫增强,胞间CO2浓度显著上升,气孔限制值变化趋势与之相反。水分利用效率总体上表现为随胁迫加剧而增强的趋势。胁迫初期,气孔限制因素与非气孔限制因素的共同作用可能导致了蚬木幼苗净光合速率的下降。蚬木幼苗在干旱胁迫下采取降低光合、增加地下生物量分配并减缓生长等适应策略,对干旱具有一定的耐受能力。土壤含水量低于最大田间持水量的65%~75%时,及时补充水分可以保证幼苗正常生长。 相似文献
5.
以4个种源(BLG、XS、LJD、JB)的蒙古莸种子培育出的实生苗为试材,对其进行不同温度的处理(3、7、11、15℃),探究不同低温胁迫条件下各种源蒙古莸在不同光强度下叶绿素荧光参数变化规律,旨在阐明其对光照环境条件变化的适应。结果表明:低温胁迫导致其PSⅡ反应中心功能下降,更易失活,对光合器官造成伤害;蒙古莸主要通过降低电子传递速率(ETR)并降低实际光化学效率(Yield)的方式降低光能捕捉效率,减少过剩光能的积累,并以此减弱光抑制带来的伤害;低温胁迫后对光破坏防御能力最差的是LJD种源。 相似文献
6.
干旱胁迫下保水剂对石楠苗生理生化特性的影响 总被引：1，自引：0，他引：1
在干旱胁迫下,对盆栽石楠苗的存活期、生长率、游离脯氨酸、可溶性糖、光合生理特性进行分析。结果表明,在有限水分条件下,施用保水剂,苗木存活期延长3.5-38.5 d;苗木生长受到抑制的时间延后0-28 d;叶片中可溶性糖和游离脯氨酸开始积累时间延后,积累量减少;净光合速率、蒸腾速率、气孔导度分别提高了5.6%-168.9%、28.6%-2 342.6%、0-4 700%。保水剂用量越大,减缓水分胁迫的能力越强。 相似文献
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8.
水分胁迫条件下白榆光合与蒸腾特性对光的响应 总被引：5，自引：0，他引：5
在不同水分胁迫条件下,即对照组（含水量90％）、轻度干旱胁迫（含水量70％）、中度干旱胁迫（含水量50％）和重度干旱胁迫（含水量40％）,以1a生白榆（Ulmus pumila）为试验苗木,分1800、1000、500、200、50和0μmol·m^-2·s^-1 6个光照强度,利用LI-6400测定白榆幼苗的光合速率、蒸腾速率和水分利用率,探讨白榆的光合特性和蒸腾特性对光强的响应。试验结果表明：不同水分梯度下白榆的光合速率随光照强度的升高呈先上升然后逐渐趋向于平稳的趋势,蒸腾速率的变化曲线与光合速率变化曲线趋势大致相同,适度干旱胁迫下,水分利用效率有一定程度的提高,水分胁迫严重时,水分利用率开始下降。说明白榆具有抗旱能力,在比较干旱的条件下也能够很好的生长。 相似文献
9.
以该区年龄相同的5种主要植被恢复树种车桑子、滇柏、侧柏、花椒和香樟幼苗为研究对象,通过盆栽控水试验,测算其在不同水分梯度下的叶绿素相对含量、净光合速率、蒸腾速率、气孔导度、胞间CO2浓度以及水分利用效率等生理生态指标,系统比较各参数的适应性变化及其差异性分析,结果表明:(1)随着干旱胁迫的加剧,5种幼苗叶片叶绿素相对含量呈现不同的变化趋势,车桑子逐渐降低,侧柏和滇柏先降后升,花椒和香樟先升后降;(2)各光合生理生态参数也呈现不同的变化规律:随干旱胁迫的加剧,净光合速率、蒸腾速率、气孔导度均逐渐降低,且在中度和重度干旱胁迫时极显著降低,其中在重度干旱胁迫时,侧柏的净光合速率最低比对照下降了100.5%,下降幅度最大;胞间CO2浓度在轻度干旱胁迫时下降,中度和重度干旱胁迫时上升;水分利用效率在轻度和中度干旱胁迫时增加,重度干旱胁迫时下降,其中香樟的水分利用效率在重度干旱胁迫时仍是对照的1.05倍;(3)综合分析各项生理生态参数,5种幼苗均能耐受一定程度的干旱胁迫,但香樟的控水耐旱能力明显高于其它4种树种,更能适应石漠化地区的生态环境。 相似文献
10.
以浙江庆元、湖南永定和湖南靖县3个种源的赤皮青冈1年生实生幼苗为试验材料,研究了土壤水分胁迫对不同赤皮青冈种源生理特性的影响,结果表明:水分胁迫50 d后,随着水分胁迫程度的加强,各供试种源的叶绿素a(Chla)含量表现为先上升后下降的趋势;叶绿素b(Chlb)含量表现为下降的趋势;丙二醛(MDA)含量表现为增加的趋势;过氧化物酶(POD)活性变化规律种源之间有差异,浙江庆元种源和湖南永定种源POD活性呈现出先升高后降低的趋势,而湖南靖县种源呈现出下降的趋势。浙江庆元种源在土壤相对含水量为60%,且胁迫时间小于30 d时,各项生理指标均显著优于其他处理。推测各种源之间抗旱性存在较大差异,3个供试赤皮青冈种源的抗旱能力大小依次为:湖南永定>浙江庆元>湖南靖县。 相似文献
11.
Oliveira DF Pereira AC Figueiredo HC Carvalho DA Silva G Nunes AS Alves DS Carvalho HW 《Fitoterapia》2007,78(2):142-145
A screening was conducted with 26 plants collected in the Brazilian southeast region, to identify plant extracts with antibacterial properties against Aeromonas hydrophila, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. Initially, the agar diffusion method was employed. Then, those extracts presenting activity were submitted to a broth microdilution assay to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). It was observed that 13 of the tested extracts showed antibacterial activity. The best results were obtained with those from Lantana lilacina and Phyllanthus tenellus. 相似文献
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The Eastern Black Sea Region has an extensive flora because of ample rainfall lasting all year. In this study, antimicrobial effects of 74 crude extracts of 22 endemic plants were investigated. Among the 30 active crude extracts, water-insoluble crude extracts from Betula medwediewii, Heracleum platytaenium, Primula longipes, Anthemis cretica ssp. argaea and Centaurea helenioides were the prominent ones with their MIC values. 相似文献
14.
The extracts from leaves, heartwood, barks and roots of the Streblus asper were investigated for anti-HBV activities, separately. The results suggested that the MeOH extracts of the heartwood, barks, and roots exhibited good anti-HBV activities. Further investigations displayed that ethyl acetate and n-butanol soluble parts of their MeOH extracts showed more significant anti-HBV activities. Moreover, a new lignan, together with 11 known compounds, was isolated from n-butanol-soluble part of MeOH extract of the roots of S. asper. The structures were elucidated by spectroscopic methods, including 1D NMR ((1)H NMR, (13)C NMR), 2D NMR (HMQC, HMBC) and HR-EI-MS experiments. Compounds 1-3 were evaluated for their anti-HBV activities. Honokiol showed significant anti-HBV activity with IC(50) values of 3.14μM and 4.74μM for HBsAg and HBeAg with no cytotoxicity respectively, while lamivudine (3TC, positive control) exhibited weak anti-HBV activity with IC(50) values of 11.81μM and 25.80μM for HBsAg and HBeAg respectively. 相似文献
15.
Growth and physiological response of six Australian rainforest tree species to a light gradient 总被引：1，自引：0，他引：1
An understanding of growth and photosynthetic potential of subtropical rainforest species to variations in light environment can be useful for determining the sequence of species introductions in rainforest restoration projects and mixed species plantations. We examined the growth and physiology of six Australian subtropical rainforest tree species in a greenhouse consisting of three artificial light environments (10%, 30%, and 60% full sunlight). Morphological responses followed the typical sun-shade dichotomy, with early and late secondary species (Elaeocarpus grandis, Flindersia brayleyana, Flindersia schottiana, and Gmelina leichhardtii) displaying higher relative growth rate (RGR) compared to mature stage species (Cryptocarya erythroxylon and Heritiera trifoliolatum). Growth and photosynthetic performance of most species reached a maximum in 30–60% full sunlight. Physiological responses provided limited evidence of a distinct dichotomy between early and late successional species. E. grandis and F. brayleyana, provided a clear representation of early successional species, with marked increase in Amax in high light and an ability to down regulate photosynthetic machinery in low light conditions. The remaining species (F. schottiana, G. leichhardtii, and H. trifoliolatum) were better represented as falling along a shade-tolerant continuum, with limited ability to adjust physiologically to an increase or decrease in light, maintaining similar Amax across all light environments. Results show that most species belong to a shade-tolerant constituency, with an ability to grow and persist across a wide range of light environments. The species offer a wide range of potential planting scenarios and silvicultural options, with ample potential to achieve rapid canopy closure and rainforest restoration goals. 相似文献
16.
Emile S. Gardiner Magnus Löf Joseph J. O’Brien John A. Stanturf Palle Madsen 《Forest Ecology and Management》2009
Efforts in Europe to convert Norway spruce (Picea abies) plantations to broadleaf or mixed broadleaf-conifer forests could be bolstered by an increased understanding of how artificial regeneration acclimates and functions under a range of Norway spruce stand conditions. We studied foliage characteristics and leaf-level photosynthesis on 7-year-old European beech (Fagus sylvatica) and pedunculate oak (Quercus robur) regeneration established in open patches and shelterwoods of a partially harvested Norway spruce plantation in southwestern Sweden. Both species exhibited morphological plasticity at the leaf level by developing leaf blades in patches with an average mass per unit area (LMA) 54% greater than of those in shelterwoods, and at the plant level by maintaining a leaf area ratio (LAR) in shelterwoods that was 78% greater than in patches. However, we observed interspecific differences in photosynthetic capacity relative to spruce canopy openness. Photosynthetic capacity (A1600, net photosynthesis at a photosynthetic photon flux density of 1600 μmol photons m−2 s−1) of beech in respect to the canopy gradient was best related to leaf mass, and declined substantially with increasing canopy openness primarily because leaf nitrogen (N) in this species decreased about 0.9 mg g−1 with each 10% rise in canopy openness. In contrast, A1600 of oak showed a weak response to mass-based N, and furthermore the percentage of N remained constant in oak leaf tissues across the canopy gradient. Therefore, oak photosynthetic capacity along the canopy gradient was best related to leaf area, and increased as the spruce canopy thinned primarily because LMA rose 8.6 g m−2 for each 10% increase in canopy openness. These findings support the premise that spruce stand structure regulates photosynthetic capacity of beech through processes that determine N status of this species; leaf N (mass basis) was greatest under relatively closed spruce canopies where leaves apparently acclimate by enhancing light harvesting mechanisms. Spruce stand structure regulates photosynthetic capacity of oak through processes that control LMA; LMA was greatest under open spruce canopies of high light availability where leaves apparently acclimate by enhancing CO2 fixation mechanisms. 相似文献
17.
从落叶松梢栖真菌筛选出对落叶松枯梢病病原菌有抑制作用的菌株,对落叶松枯梢病进行生物防治。将自落叶松梢部分离到的11种梢栖真菌与落叶松枯梢病病原菌进行对峙培养,根据被覆盖程度、抑菌率、拮抗系数和防治预试验的结果,综合评价后发现:粪生粪壳、深绿木霉和球毛壳3种梢栖真菌对落叶松枯梢病有良好的拮抗作用。利用这3个菌株在黑龙江省勃利县通天一林场国富沟进行林间防治试验,结果表明:防治效果为粪生粪壳>代森锰锌400倍液>深绿木霉>球毛壳;深绿木霉和粪生粪壳喷洒浓度50%和球毛壳喷洒浓度75%时,真菌多样性最多,梢栖真菌系统较其他浓度更为稳定,与化学防治相比,既达到了防治目的又具有不污染环境的优势。 相似文献
18.
Ungulate herbivory of regenerating conifers in relation to foliar nutrition and terpenoid production 总被引：1，自引：0，他引：1
Owen T. BurneyDouglass F. Jacobs 《Forest Ecology and Management》2011,262(9):1834-1845
Ungulate browsing greatly influences regeneration dynamics of some forest ecosystems, yet the relationship between browse susceptibility and foliar chemistry of forest tree seedlings is not well understood. We applied field fertilization (15N-9P-10K controlled-release fertilizer at 0, 20, 40, and 60 g per seedling) and investigated how subsequent changes in terpenoid production and foliar nutrition influence ungulate browse preference for Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsuga heterophylla Raf. Sarg.), and western redcedar (Thujaplicata Donn ex D. Don) seedlings across four sites in northwestern Oregon, USA. Fertilization increased foliar N concentration of all three species, but above-ground growth of only Douglas-fir and western hemlock. Foliar monoterpene concentrations for western hemlock and western redcedar also increased at higher fertilization rates, while Douglas-fir monoterpene production was not affected by fertilization. Regardless of monoterpene levels, ungulate browse preference was greater for fertilized western hemlock seedlings. The opposite response, however, was observed for western redcedar at two of the four study sites where the likelihood of browse was greater for non-fertilized than fertilized seedlings. Differences in browse preference among species may depend on the type and amount of individual monoterpenes manufactured in response to fertilization. Western redcedar produce α- and β-thujone, oxygenated monoterpenes known to promote gastroenteritis and possibly inhibit microbial rumen activity, which were absent from Douglas-fir or western hemlock. Higher concentrations of α- and β-thujone associated with increasing fertilizer rate provide a plausible explanation as to why ungulates preferred non-fertilized western redcedar. Our results illustrate species-specific adaptation in browse avoidance and selective ungulate browsing behavior of individual trees as linked to foliar chemistry. 相似文献
19.
Christopher J. Fettig Stephen R. McKelvey Daniel R. Cluck Sheri L. Smith William J. Otrosina 《Forest Ecology and Management》2010
Many forests that historically experienced frequent low-intensity wildfires have undergone extensive alterations during the past century. Prescribed fire is now commonly used to restore these fire-adapted forest ecosystems. In this study, we examined the influence of prescribed burn season on levels of tree mortality attributed to prescribed fire effects (direct mortality) and bark beetles (Coleoptera: Curculionidae, Scolytinae) (indirect mortality) in ponderosa pine, Pinusponderosa Dougl. ex Laws., and Jeffrey pine, Pinusjeffreyi Grev. and Balf., forests in California, USA. A total of 816 trees (9.9% of all trees) died during this 3-yr study. Significantly higher levels of tree mortality (all sources) occurred following early and late season burns compared to the untreated control, but no significant difference was observed between burn treatments. The majority (461 trees) of tree deaths were attributed to direct mortality from prescribed burns and was strongly concentrated (391 trees) in the smallest diameter class (<20.2 cm diameter at breast height, dbh). For the largest trees (>50.7 cm dbh), significantly higher levels of tree mortality occurred on early season burns than the untreated control, most of which resulted from indirect mortality attributed to bark beetle attacks, specifically western pine beetle, Dendroctonus brevicomis LeConte, and mountain pine beetle, D. ponderosae Hopkins. Red turpentine beetle, D. valens LeConte, was the most common bark beetle species found colonizing trees, but tree mortality was not attributed to this species. A total of 355 trees (4.3% of all trees) were killed by bark beetles. Dendroctonus brevicomis (67 trees, 18.9%) and D. ponderosae (56 trees, 15.8%), were found colonizing P. ponderosa; and Jeffrey pine beetle, D. jeffreyi Hopkins, was found colonizing P. jeffreyi (seven trees, 2.0%). We also found pine engraver, Ips pini (Say) (137 trees, 38.6%), and, to a much lesser extent, Orthotomicus (=Ips) latidens (LeConte) (85 trees, 23.9%) and emarginate ips, I. emarginatus (LeConte) (3 trees, 0.8%) colonizing P. ponderosa and P. jeffreyi. Few meaningful differences in levels of indirect tree mortality attributed to bark beetle attack were observed between early and late season burns. The incidence of root and root collar pathogens (Leptographium and Sporothrix spp.), including species known to be vectored by bark beetles, was low (18% of trees sampled). The implications of these and other results to management of P. ponderosa and P. jeffreyi forests are discussed in detail. 相似文献
20.
Euphorbia acanthothamnos, E. macroclada and E. rigida were investigated for their antioxidant activity. The antioxidant potential of extracts of E. acanthothamnos, E. macroclada and E. rigida was evaluated using different complementary antioxidant tests. 相似文献