干旱胁迫对4个油茶品种苗木生理生化指标的影响

为给耐旱性油茶品种的选育提供科学依据,以‘华鑫’‘华硕’‘长林40’和‘长林4号’这4个红壤丘陵区主栽油茶品种2年生嫁接苗为研究材料,采用盆栽控水的方法,分别设置了重度干旱胁迫、中度干旱胁迫和对照3种处理进行试验,对4个油茶品种在不同干旱条件下11个生理生化指标的变化情况进行了观测,并采用隶属函数法对4个油茶品种苗木的抗旱性进行了综合评价。试验结果表明:随着干旱程度的加重和干旱时间的延长,4个油茶品种苗木叶片叶绿素含量都有不同程度的降低,其中‘华硕’的下降幅度最大,为40.96%;其净光合速率、气孔导度、叶片蒸腾速率都呈下降趋势,其平均下降率分别为12.81%、48.03%、42.54%;其超氧化物歧化酶、过氧化物酶、可溶性糖、游离脯氨酸随着干旱条件的变化均呈现出先升后降的变化趋势,而其丙二醛含量则呈持续增长趋势。隶属函数分析结果表明,4个油茶品种抗旱性的强弱顺序为:‘长林40’>‘长林4号’>‘华硕’>‘华鑫’。     

持续干旱对油茶叶片及根系生理生化指标的影响

以"湘林52"2年生油茶嫁接苗为材料,采用盆栽的试验方法,利用自然干燥法获得控水梯度,测定持续干旱条件下油茶苗叶片光合色素,叶片及根系(D≤2 mm)丙二醛、脯氨酸、可溶性糖、可溶性蛋白、超氧化物歧化酶、过氧化物酶和过氧化氢酶生理生化指标,研究其对干旱胁迫的生理响应。结果表明:随着干旱程度的增加,叶片光合色素含量持续降低(P0.05);叶片及根系丙二醛、脯氨酸和可溶性糖含量均持续增加(P0.05),叶片可溶性蛋白含量持续降低(P0.05),根系可溶性蛋白含量先增加后下降(P0.05);叶片及根系超氧化物歧化酶活性持续增加(P0.05),过氧化物酶和过氧化氢酶活性均呈先升高后降低的变化趋势(P0.05)。当土壤相对含水量高于30.6%时,复水后油茶苗能恢复正常生长;当土壤相对含水量低于21.1%时,复水后油茶苗不能恢复正常生长。     

花吊丝竹对干旱胁迫的光合和生理响应

通过盆栽实验,研究了花吊丝竹在自然耗水的干旱胁迫处理下土壤含水量、叶片水势、叶片光合作用参数、叶绿素荧光参数以及相关酶类生理指标的变化。结果表明:(1)干旱胁迫下,土壤含水量与叶片水势显著下降,叶片的净光合速率、气孔导度和蒸腾速率均有不同程度下降,胞间CO2浓度呈先降后升的趋势,而气孔限制值则呈先升后降的趋势,说明轻度干旱胁迫下,气孔限制是花吊丝竹净光合速率降低的主要因素,重度干旱胁迫下,非气孔限制是净光合速率降低的主要因素。(2)花吊丝竹叶片光系统Ⅱ的实际光化学效率、表观光合电子传递速率和非光化学猝灭系数在胁迫后段(15~30 d)呈显著下降趋势,而叶片初始荧光在后期呈上升趋势,表明随胁迫程度加重,PSⅡ的结构受到较严重的损伤。(3)随干旱时间的延长,脯氨酸和丙二醛的含量均显著上升,而超氧化物歧化酶和过氧化氢酶的活性则先升后降,这表明随胁迫程度加深花吊丝竹细胞结构被破坏。综上所述,干旱胁迫环境下,花吊丝竹叶片光合作用和保护酶类均发生相应的变化,其自身能够提高叶片对光能的捕获能力、提升光能转化效率、增强叶片中的酶活性以及减少热能的耗散等形式,实现对干旱胁迫较强的忍耐性和较好的适应性。     

4种地被植物干旱胁迫下的生理响应及抗旱性评价

为了丰富关中地区园林地被植物种类,让园林企业在合理选择和应用地被植物有可靠的理论依据,以关中地区引种栽培的顶花板凳果、大吴风草、迷迭香和蜘蛛抱蛋4种常绿地被植物2年生盆栽苗为试材,采用人工控水模拟水分胁迫的方法,研究其在不同程度下的植株形态变化,并测定4种植物的萎蔫系数及叶片的游离脯氨酸、MDA、SOD、POD、CAT、可溶性蛋白以及可溶性糖等生理生化指标的变化,由此来综合评价其抗旱性。结果表明:1)从干旱临界值来看,迷迭香的最低,达到3.01%;2)从叶片游离脯氨酸含量变化来看,顶花板凳果、大吴风草及迷迭香随着干旱胁迫程度的增加呈现增长趋势,到了重度干旱胁迫,其含量分别达到对照的7.09倍、11.73倍、18.59倍;3)从MDA含量变化来看,大吴风草和迷迭香叶片中的含量同干旱胁迫程度呈正相关,蜘蛛抱蛋、顶花板凳果则整体呈现缓慢的下降趋势;4)随着干旱胁迫程度的增加,4种植物叶片可溶性蛋白含量变化均有所增加,但差异不显著。可溶性糖的含量只有蜘蛛抱蛋呈现先升后降的趋势,其余3种均呈现显著连续下降趋势;5)从叶片保护酶活性分析,干旱胁迫条件下SOD、POD和CAT均有所增加。其中顶花板凳果、大吴风草及蜘蛛抱蛋的CAT含量显著增加,增长率分别达159.28%、239.31%和200.97%;6)利用隶属函数分析4种常绿地被植物的抗旱性强弱,其顺序为:迷迭香>顶花板凳果>蜘蛛抱蛋>大吴风草,这一结果与盆栽干旱试验的形态表现一致。     

干旱胁迫对5种园林绿化植物生理生化的影响

为给抗旱性较强的城市园林绿化植物的筛选提供依据,以5种园林绿化植物蛇莓、蛇莓萎陵菜、东北玉簪、紫萼玉簪和大萼铁线莲为试材,在持续干旱条件下,研究了园林绿化植物的渗透调节和抗氧化酶活性的响应特性。结果表明,持续15d干旱降低了土壤田间持水量,5种植物叶片水势和净光合速率随之下降。但是,蛇莓叶片水势和净光合速率降低的幅度比其它4种植物降低幅度小。干旱胁迫提高了叶片的丙二醛含量,细胞膜脂发生了过氧化。在持续15d干旱过程中,蛇莓和蛇莓萎陵菜叶片SOD活性增强。因此,蛇莓和蛇莓萎陵菜在干旱胁迫下能保持相对较高的光合速率,并利用酶促和非酶促系统清除氧自由基,表现出较强的抗旱能力。     

CO2倍增与干旱胁迫交互作用对幼树蒸腾耗水日变化的影响

采用BP3400精密电子天平和Licor-7000开路式CO2/H2O分析仪,于2007年夏季研究了不同CO2浓度梯度和不同干旱胁迫水平下,4种幼树的实际耗水量及蒸腾耗水速率的日变化规律。结果表明,在各干旱胁迫水平下,CO2浓度倍增有效地降低了幼树的蒸腾耗水量和耗水速率。在干旱胁迫后期,白蜡、丁香、黄杨、侧柏的日平均耗水量分别比对照下降了42%、52%、37%和19%;日平均耗水速率平均下降了50%-65%。经过CO2倍增处理后,4种幼树的叶面积都明显增加,并且连续处理时间越长,效果越明显。     

猕猴桃园套种蕺菜对土壤养分、酶活性及果实品质的影响

为了提高猕猴桃果实产量与品质,在猕猴桃园以套种蕺菜、清耕和对照作为试验处理,测定不同时期猕猴桃根际土壤养分含量、微生物数量、酶活性和果实产量及品质,分析其相关性。结果表明:套种蕺菜后猕猴桃根际土壤碱解氮、速效磷、速效钾含量分别比对照处理提高13.95%、7.92%和3.94%,土壤细菌、真菌、放线菌数量分别提高19.01%、28.89%和16.32%,土壤过氧化氢酶、脲酶、蔗糖酶、磷酸酶活性分别提高17.02%、12.63%、17.57%和7.98%,单果质量和单位面积产量分别提高7.14%和7.68%,维生素C、干物质、可溶性固形物、可溶性总糖和可滴定酸含量分别提高7.97%、18.29%、2.09%、12.37%和14.18%。相关性分析结果表明,套种蕺菜后猕猴桃根际土壤速效钾含量与土壤中细菌数量、真菌数量、放线菌数量、脲酶活性、蔗糖酶活性、磷酸酶活性极显著正相关。土壤细菌数量与蔗糖酶活性显著正相关,与磷酸酶活性极显著正相关。土壤真菌数量与蔗糖酶活性极显著正相关。土壤放线菌数量与蔗糖酶活性、磷酸酶活性显著正相关。土壤速效磷含量与维生素C含量、可滴定酸含量极显著负相关,与干物质含量、可溶性固形物含量和可溶性总糖含量极显著正相关。土壤细菌数量、放线菌数量与维生素C含量极显著负相关。土壤真菌数量与维生素C含量显著负相关。土壤脲酶活性与干物质含量显著正相关,与可滴定酸含量显著负相关。维生素C含量与土壤蔗糖酶活性极显著负相关,与土壤磷酸酶活性显著负相关。套种蕺菜有利于提高猕猴桃根际土壤养分含量、微生物数量和酶活性,增加猕猴桃果实产量,改善猕猴桃果实品质。     

肥料与调节剂对山茱萸生长以及保护酶活性的影响

讨论不同施肥量和不同植物生长调节剂浓度对山茱萸移栽苗苗木质量以及保护性酶的影响.结果表明:施肥量与植物生长调节剂浓度配合较好的处理有2个,1施肥量为尿素0.039 kg/m2,过磷酸钙0.077 kg/m2,氯化钾0.019 kg/m2,植物生长调节剂浓度为578.3 mg.kg-1(按多效唑与6-苄氨基腺嘌呤质量比1∶1)或者施肥量为尿素0.020 kg/m2,过磷酸钙0.040 kg/m2,氯化钾0.010kg/m2,植物生长调节剂浓度为600 mg.kg-1(多效唑与6-苄氨基腺嘌呤质量比1∶1);2SOD活性可作为山茱萸抗寒性生理指标,用于山茱萸及种源抗寒性选择,POD和CAT活性仅作为参考指标.     

土壤盐分胁迫对三种暖季型草坪草保护酶活性及脂质过氧化作用的影响

对土壤盐分胁迫下的3种暖季型草坪草的保护酶活性以及脂质过氧化作用进行了研究。结果表明：0．6％～0．8％土壤盐分胁迫下的假俭草各类保护酶活性(SOD、CAT、POD、APX)随胁迫时间的延长逐渐下降，0．2％～0．4％盐分胁迫的假俭草以及结缕草、沟叶结缕草随盐分胁迫程度的增加，保护酶活性上升。MDA、RPP均随胁迫程度的增加和胁迫时间的延长，逐渐升高，其中上升幅度最大的是假俭草，最小的是沟叶结缕草。PAL活性，三种草坪草除0．8％条件下假俭草呈现先升后降的趋势外，其余均随盐分浓度的升高而上升。各类保护酶的活性大小和MDA含量、RPP高低，与三种草坪草的耐盐能力有关，认为耐盐能力最强的是沟叶结缕草，最弱的是假俭草。     

Effects of soil drought on seedling growth and water metabolism of three common shrubs in Loess Plateau, Northwest China

The growth and water metabolism of three common shrubs on the Loess Plateau were studied under soil with different water contents. Results showed that water consumption of those species decreased with the increase in drought stress, and water consumptions of these shrubs were different: Forsythia suspensa was the greatest, and Syringa oblata was the lowest. The growth rate of new branches and leaf area of three species were the fastest under adequate soil water conditions, and were the lowest under severe drought. Under the same water conditions, the growth of F. suspensa was the fastest while that of S. oblata was the slowest. The water content, proline and chlorophyll content of different species changed with the increase in soil water stress. The leaf water content of Periploca sepium and F. suspensa was obviously higher than that of S. oblata, while the leaf proline content of F. suspensa and S. oblata was lower than that of P. sepium. The ratio leaf chlorophyll a: b of F. suspensa and S. oblata decreased with the decrease in soil water content. Although these three shrubs had different mechanisms in response to drought stress, they all had higher drought resistance and could adapt to the drought condition on the Loess Plateau. This paper provided some bases for choosing tree species on the Loess Plateau. __________ Translated from Acta Botanica Boreali-Occidentalia Sinica, 2007, 27(1): 91–97 [译自: 西北植物学报]     

Features of soil enzyme activities and the number of microorganisms in plantations and their relationships with soil nutrients in the Qinling Mountains, China

We studied the distribution of soil nutrients, the number of soil microorganisms, soil enzyme activities, and their relationships in pure and mixed plantations. Soil enzyme activities, the number of soil microorganisms, and soil nutrients were measured in plantations of Chinese pine (Pinustabulaeformis), larch (Larix kaempferi), sharp tooth oak (Quercus aliena var. acuteserrata), Manchurian catalpa (Catalpa fargesii), and mixed plantations in the Qinling Mountains, China. Compared with pure plantations, the conifer-broad-leaved broadleaf mixed plantations increased total N, available N, total P, available K, and organic matter in the forest soil; promoted the activities of invertase and urease by 16.7% and 53.8%; and increased the total amount of soil microorganisms by 95.9% and the number of bacteria by 104.5% (p<0.05). The correlations between soil enzymes, number of microorganisms, and soil nutrients were significant (p<0.05), and the correlations between the number of soil bacteria and basic nutrient prosperities (total N, available N, available K, and organic matter (OM)) were significant or highly significant. The correlations between the number of soil actinomycetes, and soil total N, available N, OM, and pH were also significant or highly significant. A suitable mixture of planted conifers and broad-leaved species improves the quality and amount of soil nutrients, increases the number of soil microorganisms and changes their redistribution. The change of soil enzymes and the number of soil microorganisms are indications of the change tendency of soil nutrients. __________ Translated from Journal of Northwest A&F University (Nat. Sci. Ed.), 2008, 36(10): 88–94 [译自: 西北农林科技大学学报]     

Incentives for Participation by Local Communities in the Establishment of Commercial Plantations in Sichuan Province, China

The 1998 floods in China triggered the implementation of the Natural Forest Conservation Program (NFCP) which includes: (i) a logging ban over state-owned natural forests in order to protect the deteriorating natural environment, and (ii) strategies for the establishment of commercial plantations and relocation of laid-off forest workers, with the aim of mitigating the negative socioeconomic impacts of the logging ban. In this paper, Sichuan province is used as a case study to analyze the disincentives faced by local communities in developing commercial plantations and the institutional failure to address the disincentive issue. Insight on the necessity of 'real participation' of local communities has been provided, and ways to create incentives as well as institutional rearrangement has been explored and recommended.     

Changes induced by osmotic stress in the morphology,biochemistry, physiology,anatomy and stomatal parameters of almond species （Prunus L. spp.） grown in vitro

We investigated the influence of different levels of osmotic stress on growth and development in selected wild almond species(eight Prunus spp.) grown in vitro. The study, while endorsing the efficacy of in vitro screening of auxiliary buds of wild almond for osmotic stress tolerance, showed species variability in its response to osmotic stress. Osmotic stress reduced growth and development of all the species. However, the putative tolerant Prunus spp. showed better performance than the putative susceptible genotypes. On average there was an 80% decrease in shoot dry weight at-1.2 MPa. Reduction in shoot weight was more common in osmotic stress-susceptible species in the section labeled ‘Euamygdalus'. The tolerant Prunus species produced smaller changes in biochemical responses than the sensitive cultivars for malondialdehyde content, catalase activity, relative permeability of protoplast membranes, and net photosynthetic rate. The tolerant species maintained cell integrity better than drought sensitive species. Wild almond species in the section labeled ‘Spartioides'(Prunus arabica(Olivier) Neikle, Prunus glauca (Browicz) A.E. Murray, Prunus scoparia Spach) and ‘Lycioides'(Prunus lycioides Spach, Prunus reuteri Bossi. et Bushe) were best adapted to osmotic stress. Increase in chlorophyll concentration and leaf thickness under high osmotic stress can be considered as preliminary selection parameters for osmotic stress tolerance in Prunus spp. The study confirmed the efficacy of the in vitro method for screening of large number of genotypes for osmotic stress tolerance in wild almond species.     

黑河流域荒漠地区水分胁迫对梭梭苗木影响的试验研究(英文)

梭梭(HaloxylonAmmodendronBge,一种C4灌木)苗种植在15升的容器中,给予不同的水分胁迫处理,研究了其水分关系和气体交换特征。结果表明:当土壤水分含量大于11%时,梭梭苗有高的蒸腾量;土壤水分含量低于6%时,苗木就不能从土壤中吸取水分;很好供水的苗木的蒸腾量与潜在蒸发量成线型相关。气体交换测定发现,随着土壤水分含量的下降,造成了不同程度的气孔导度、叶蒸腾强度和光合作用的下降。对同一苗木而言,由于这个地区有高的水气压亏缺(VPD),很好和中度供水的苗木在气孔反应方面有较宽的范围,气孔在决定光合作用方面起着较小的作用,二者没有明显的线型相关关系。虽然水分胁迫使蒸腾速率比光合速率下降的更快,提高了水分利用效率,而较高的蒸发需求增加了蒸腾量,限制了光合作用,但是总的趋势是光合作用和蒸腾强度成线型相关。图6表2参15。     

Changes in the biochemical composition and enzyme activity during dormancy release of Cyclocarya paliurus seeds

Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes in biochemical composi-tion and enzyme activity were investigated during dormancy release. The activities of all the studied enzymes in the stratified seeds increased significantly, compared to those in the control samples. Of the enzymes examined, the activities of protease increased the most (413.8%), followed by peroxidase (278.7%), lipase (161.0%), glucose-6-phosphate dehydrognase (149.1%) and amylase (60.6%) after 8 months of stratification. Crude fat and protein constituted the bulk of the storage reserves in mature seeds of C. pali-urus. Compared with the seeds before stratification, about 45% of the starch, 46% of the protein and 11% of the crude fat were de-pleted during dormancy release of C. paliurus seeds, while the soluble sugar content was enhanced by 101.5% in the germinating seeds. Correlation analysis showed, during dormancy release of C. paliurus seeds, a close positive relationship between POD and G6PDH activity as well as soluble sugar content and amylase activity, while there was a significant negative relationship between storage substances and their related enzyme activities.     

Effects of landscape restoration on soil water storage and water use in the Loess Plateau Region,China

Large-scale vegetation restoration in China's Loess Plateau has been initiated by the central government for controlling soil and water losses in the past three decades. However, there is virtually no guidance for plant species selection for the restoration purpose. We investigated the effects of planting trees and shrubs, land-use conversions from croplands to pastures and native grasslands on soil water dynamics and water stresses by using long-term field measurements from 1986 to 1999 in the semi-arid loess hilly area. Our research has led to the following three major findings. Firstly, the amount of soil water storage within a 100 cm depth decreased as measured at both the beginning and the ending point of growing seasons regardless land cover types. The soil water replenishment by rainfall during rainy seasons was not sufficient to fully recharge the soil water storage. Landscape restoration through shrub planting may help retain more soil water than other land cover types. Secondly, the ratio of actual evapotranspiration (ET) and pan evaporation (PET) generally declined for all land cover types during the study period. Shrub lands had the largest ET/PET ratio, followed by native grassland, cropland/alfalfa, and pine woodland. The ET/PET ratio of native grasslands declined fastest, followed by pine woodlands, shrub lands, alfalfa, and croplands. Pine woodland's low ET/PET ratios were mainly caused by its higher runoff due to soil compaction resulted from soil desiccation. Lastly, we found that the soil water storage at the beginning of growing season was important in determining the ET/PET ratios. This study suggested that pine plantations may not be appropriate for landscape restoration in such a semi-arid loess hilly area while shrubs may be highly recommended.     

岷江上游干旱河谷辐射松引种造林研究

经过连续14 a的辐射松(Pinus radiata D.Don)引种造林研究,结果表明(1)采用1.5 m×2.0 m造林密度,短册状或水平沟整地,采用石块、塑料薄膜覆盖,造林成活率达96%,保存率达90%.(2)抚育压青6 a的辐射松幼树树高生长量为对照的2.02倍,地径生长量为对照的2.19倍;每株幼树施20 g(N)+100g(P)施肥量的树高生长量比对照提高65.7 cm～120.2 cm,地径生长量比对照提高1.74 cm～3.83 cm;1/3修枝强度比对照树高生长量提高295.7 cm,地径生长量提高3.0 cm,1/4修枝强度比对照树高提高198.1 cm、地径生长量提高2.54 cm;(3)辐射松1 a中有2次高生长高峰期、3次径生长高峰期,高、径速生期在4～6龄年出现,幼林的根系、枝干、叶的生物量在5 a生时也急剧增加.     

Changes in species composition and diversity in the restoration process of sub-alpine dark brown coniferous forests in western Sichuan Province, China

By adopting the concept of space as a substitute for time, we analyzed the dynamics of species composition and diversity of different restoration sequences (20, 30, 40, 50 years) in two secondary forest types in western Sichuan Province, distributed in a northerly or northwesterly direction. The analysis was based on the results of measurements of 50 plots located at elevations between 3100–3600 m. The forests originated from natural regeneration in combination with reforestation of spruce when the old-growth bamboo-dark brown coniferous forests and moss-dark brown coniferous old growth forests were harvested. Similar old-growth dark brown coniferous forests at ages ranging between 160 and 200 years were selected as the reference forests for comparisons. We recorded 167 species of vascular plants from 44 families and 117 genera. There was no significant difference in terms of the number of species among secondary forests. But the importance values of dominant species varied during the restoration processes. The dominant species in the secondary forests is Betula albo-sinensis, while Abies faxoniana is the dominant species in old-growth dark brown coniferous forests. Species richness increased significantly with restoration processes. It increased quickly in secondary forests during the period from 30 to 40 years, but decreased significantly in the old-growth dark brown coniferous forests. The species richness among growth forms decreased in the following order: herb layer > shrub layer > tree layer. The maximum value of the evenness index occurred in secondary forests at age 40 and remained relatively stable in the bamboo-birch forests, but the evenness index tended to decrease in moss-birch forests and slightly increased in the old-growth mossdark brown coniferous forests. There was a statistically significant difference in the eveness index between the tree and shrub layers as well as between the tree layer and the herb layer, but there was no significant difference between the shrub layer and the herb layer. The value of the Shannon index increased over restoration time. In bamboo-birch forests, the maximum value of the Shannon index was 3.80, recorded at age 50. In moss-birch forests, the maximal value was 3.65, reached in this forest at age 30. The value of the Shannon index of old-growth dark brown coniferous forests was recorded between younger secondary and older secondary forests. The value of the dominance index of communities varied. At the first stage of restoration, it increased, and at the end it was decreased. The dominance index of the tree layer had a similar trend as that of the community dominance index, but was more variable. The minimum value of the dominance index of the tree layer in the moss-birch forests reached 20 years earlier than that of the bamboo-birch forests. There was a significant difference among restoration sequences in the α diversity indices except for the dominance index. No significant differences between the two secondary forest types were detected. Over age, the value of the Bray-Curtis index between secondary forest and old-growth dark brown coniferous forest increased. __________ Translated from Scientia Silvae Sinicae, 2007, 43(5): 17–23 [译自: 林业科学]     

四川西部高山峡谷区森林分布特点及其演替规律

自从1950年以来,在四川西部高山峡谷区设置了700块样地,对该区域森林分布特点及森林演替与环境梯度间的关系进行研究.结果表明,高山峡谷区森林建群种以冷、云杉两属树种为优势,形成90多种森林类型;冷杉林多分布于各河流及其支流的中、上部,而云杉林多分布于宽谷地带和半阴半阳坡;冷云杉林冠下天然更新不良,而林窗天然更新效果较好;森林演替与垂直梯度关系密切;演替途径与原林型林下植被层片有关;人为措施可以促进或延缓演替进程;扩张更新效果常受地形、植被、风向影响。图4参9。