金沙江干热河谷造林树种游离脯氨酸含量与抗旱性关系

金沙江干热河谷地区的主要造林树种中,以马占相思、山毛豆、真珠相思、大叶相思、台湾相思、绢毛相思、坡柳在旱季游离脯氨酸累积较多;赤桉、泰国赤桉、柠檬桉、尾叶桉、大叶桉、新银合欢、苏门答腊金合欢、滇刺枣无明显差异。无论从种属间或种源地,还是不同生态类型,都看不出游离脯氨酸的累积与抗旱性之间有明显的相关关系。作者认为,用游离脯氨酸作为植物抗旱性指标有一定局部性,但用它作为某些树种在干旱胁迫时植物体发生变化的一个比较敏感的参数或指标则比较适合     

金沙江干热河谷能源林树种及其培育技术

以元谋干热河谷几种适应性强、生长快、薪材产量高、热值高的能源林树种为研究对象,在调查树种生态适应性基础上,比较了不同整地方式对造林效果的影响,同时对不同树种薪炭材产量和热能潜力进行比较分析。结果表明:元谋盆地为代表的金沙江干热河谷培育农村能源林,最适宜树种是赤桉(泰)、柠檬桉、赤桉、尾叶桉、新银合欢等,局部水肥条件好的地方可以选种大叶相思、马占相思等树种;这些树种均以撩壕整地的造林效果好于块状整地;各树种生物量及固定太阳辐射能的能力均以赤桉(泰)、柠檬桉、尾叶桉、赤桉和新银合欢较高。提出了在金沙江干热河谷地区培育农村能源林,应该选择赤桉、柠檬桉、尾叶桉和新银合欢等树种,采用容器育苗、撩壕整地、追施有机基肥、雨季初期取苗造林等综合配套的营造林技术。     

元谋县干热河谷引种植物评价

2004-2005年以“三个效益”为标准,对元谋县金沙江干热河谷区引种栽培的树种进行了调查,结果认为引种是成功的,以用材为主的生态林树种为:加勒比松、赤桉、柠檬桉、尾叶桉、苏门答腊金合欢、新银合欢、大叶相思;以林果为主的经济林树种为:毛叶枣、龙眼、芒果、甜酸角。木豆和山毛豆可作为木本饲料种植。     

元谋县干热河谷引种植物评价

2004～2005年以"三个效益"为标准,对元谋县金沙江干热河谷区引种栽培的树种进行了调查,结果认为引种是成功的, 以用材为主的生态林树种为加勒比松、赤桉、柠檬桉、尾叶桉、苏门答腊金合欢、新银合欢、大叶相思;以林果为主的经济林树种为毛叶枣、龙眼、芒果、甜酸角.木豆和山毛豆可作为木本饲料种植.     

金沙江干热河谷人工林不同林分结构对林地土壤肥力影响的初步研究

对干热河谷人工林不同林分结构下土壤营养进行了分析,结果表明:新银合欢、山毛豆纯林、新银合欢、山毛豆与赤桉的混交林分对提高林地土壤的肥力效果显著,赤桉纯林较差.但山毛豆在本区自然寿命短,无自然更新能力,不宜营造纯林,只能作为相思类乔木的混交树种,而赤桉则宜与新银合欢混交.     

云南省红河州石漠化治理树种叶的结构研究

通过石蜡切片和显微测量，研究了云南省红河州石漠化治理树种属内种间叶的结构及抗旱性的差异。结果表明：松属有2个指标存在差异，即表皮厚（马尾松-加勒比松〉细叶云南松）和下皮厚（加勒比松〉细叶云南松〉马尾松）；柏木属有2个指标存在差异，即总厚度和上表皮厚（均为墨西哥柏〉冲天柏）；按属有4个指标存在差异，即上角质层厚、下角质层厚、栅栏组织厚（均为赤桉〉直干桉）和海绵组织厚（赤桉〈直干桉）；金合欢属有6个指标存在差异，即总厚度、上表皮厚、下表皮厚、腹侧栅栏组织厚、背侧栅栏组织厚和贮水组织厚（均为肯氏相思〉大叶相思）。因此，如果仅从叶的结构来比较抗旱性，则松属中加勒比松〉马尾松〉细叶云南松；柏木属中墨西哥柏〉冲天柏；桉属中赤桉〉直干桉；金合欢属中肯氏相思〉大叶相思。     

3种相思幼苗抗旱性研究

以聚乙二醇（PEG-6000）的渗透溶液模拟水分胁迫条件，比较了不同水分胁迫强度下3种相思幼苗的抗旱性，并确定了鉴定幼苗抗旱性的生理指标。结果表明：相对电导率、相对含水量、相对水分亏缺、可溶性糖含量、游离脯氨酸等指标可作为鉴定相思幼苗早期抗旱性的生理指标；3个树种的抗旱能力排序为：厚荚相思〉大叶相思〉马占相思。     

金沙江干热河谷几类人工林的调查报告

金沙江干热河谷地区采用乔、灌、草相结合的造林模式营造的人工林,表现出较好的适应性.从生态、经济、社会的综合效益情况看,在金沙江干热河谷地区造林,认为合欢类、大叶相思与赤桉或尾叶桉混交或营造加勒比松纯林较好.金沙江干热河谷人工林中几种较成功的造林树种,3～5a生的以加勒比松和尾叶桉材积生长率最高为72.2%,5～10a生的以尾叶桉材积生长率最高为69.2%,赤桉为44.8%,柠檬桉为50.0%.     

海南半干旱地区薪材树种的选择

在海南半干早丘陵台地区,对窿缘桉、大叶相思、木麻黄、新银合欢、银合欢、刚果12号桉和雷林1号桉进行了筛选试验,结果表明:刚果12号桉、雷林1号桉、窿缘桉和大叶相思适应性强,生长快,生物量高,燃烧性能好,经济效益高,是适于当地生长和发展的优良薪材树种。     

胶园防护林更新要对种的选择

通过对１０个树种１－４年生的保存率、风害状况、林木生长表面的对比研究，运用模糊综合评判，选择的胶园防护林树种。初步结果表明，赤桉、细叶桉、刚果１２号桉适宜作为园防护林更新树种，山地木麻黄和大叶相思亦较适宜，其余树种均不适宜。     

金沙江干热河谷造林树种游离脯氨酸 含量与抗旱性关系

The accumulation of free proline in some major tree species growing in dry and hot river valley of Jinsha during both dry and rainy seasons has respectively been determined.The result shows that the free proline content in Acacia manguim,Tephrosia candida,A.podalyriifolia,A.auriliformia,A.confusa,A.holosericea and Dodonaea viscosa increased significantly than in any other species in dry season.No observable changes have been found as for the content of free proline in Eucalyptus camaldulensia,E.camaldlensia from Thailand,E.citriodora,E.urophylla,E.robusta,Leucaena leucocephala,Acacia glauca,Zizyphus mauritiana in both seasons.There is not obvious interrelation between the accumulation of free proline and drought resistance in the plants whether among different species,or among the same tree species from different area,or from different ecological forms.It seems that there is certain limitation to utilize the content of free proline as the indices as plant drought resistance.However,using the free proline as indices or parameter to determine the physiological change in some plants under water stress is suggested.     

金沙江干热河谷区8个造林树种的生态适应性变化

对金沙江干热河谷区8个造林树种的有关生理生态特性进行了研究。结果表明:相思类树种在旱季水分自然饱和亏缺较大,乡土树种坡柳和3种桉树则是雨季水分亏缺较大,具有WSD高而RWC低的植物同样具有很强的抗旱能力;比叶面积增大是植物提高抗旱能力的一个表现方面,但增加干物质积累、提高细胞质浓度也是途径之一;干热逆境可造成叶绿素含量降低,雨季叶绿素含量有较大提高,叶绿素a/b值也随之得到提高;参试树种的糖分含量旱季比雨季高,除马占相思外,其它树种淀粉与糖的比率则旱季比雨季低;在干热逆境胁迫下,7个树种(除尾叶桉)的游离脯氨酸含量有不同程度增加,旱季植株易出现萎蔫现象,有部分或较多叶片脱落的树种积累的游离脯氨酸较多。除造林效果较差的马占相思与其它7个树种有较多差异外,造林效果较好的7个树种在生理生态变化方面有较多相似性;同时,同类树种间有明显的一致性;乡土树种坡柳则在某些方面更近似于相思类树种,在某些方面又近似于桉树类树种;除马占相思外,3个相思类、3个桉树类树种与乡土树种坡柳同样在金沙江干热河谷区表现出较强的生态适应性。     

Seasonal variability of photosynthetic characteristics influences growth of eight tropical tree species at two sites with contrasting precipitation in Panama

Relative to closed-canopy tropical forests, tree seedlings planted in open grown areas are exposed to higher light intensity, air temperatures, vapor pressure deficit, and greater seasonal fluxes of plant available water than mature tropical forests. The species-specific adaptive capacity to respond to variable precipitation and seasonality in open grown conditions, therefore, is likely to affect species performance in large-scale reforestation efforts. In the present study, we compared the photosynthetic characteristics of eight tropical tree species within and between seasons at two study sites with contrasting dry season intensities. All species except Pseudosamanea guachapele reduced leaf physiological function between the wet and dry seasons. The contrasting severity of seasonal drought stress at the study sites constrained growth rates and photosynthetic characteristics differently. Variation of photosynthetic characteristics at the species level was high, particularly in the dry season. Faster growing species at the less seasonal site, Terminalia amazonia, Inga punctata, Colubrina glandulosa, and Acacia mangium, exhibited a greater adaptive capacity than the other species to down-regulate leaf photosynthesis between seasons. As the dry season was more severe at the more seasonal site, most species strongly reduced physiological function regardless of relative growth rates, except two species (Tectona grandis and P. guachapele) with widespread distributions and relatively high drought tolerance. Our results underscore the need to consider seasonal drought tolerance when selecting tree species for specific reforestation sites.     

Performance of eight tree species in the highland Vertisols of central Ethiopia: growth, foliage nutrient concentration and effect on soil chemical properties

The coverage of trees in the highland Vertisol areas of Ethiopia is very scarce. A tree screening trial was conducted from 1997 to 2002 in Ginchi (central Ethiopia) to select fast growing and high biomass producing tree species; evaluate foliage macronutrient concentration of different tree species; and assess effects of trees on soil chemical properties beneath their canopies. Acacia decurrens Willd, A. mearnsii De Wild and Eucalyptus globulus Labill attained the highest height growth at 64 months as compared to other indigenous and exotic species. E. globulus provided better height increment from 24 to 36 and 36 to 64 months than other tree and shrub species. Acacia mearnssi and A. saligna Labill Wendl produced high biomass at 40 and 64 months. Differences between the highest and lowest dry biomass at 12, 40 and 64 months were 1.13, 29.19 and 38.89 kg tree⁻¹, respectively. None of the tree species resulted in a foliage to stem biomass ratio of >0.98 at 40 and 64 months. Sesbania sesban (L.) Merr had high N and P concentrations in its foliages and stems at 12 and 40 months. Total N under Acacia abyssinica Hochst. Ex Benth, A.␣saligna and S. sesban was slightly greater at 40 months than 12 months.     

Fruit production ofAcacia tortilis andA. nilotica in semi-arid Ethiopia

Dry, dehiscent fruits ofAcacia tortilis provide important fodder for pastoral livestock in dry seasons on the central Borana Plateau, fruits ofA. nilotica may also be useful during drought. Information was needed on fruit yield to assess what these species could contribute to improved calf feeding systems based on local resources. Fruit production of 10 mature trees per species was measured at five sites for seven months during 1988–9 (n=50 per species). Fruit yields varied according to site, season and species x site (each atP<0.001), but there was no main effect of species (P=0.13). Yields were not correlated with trunk diameter at breast height (DBH) or canopy area within or across species (P>0.05 in all cases). Yields ranged from 0 to 40 kg DM per tree overall, with an average of 5.3 kg DM per tree (or 65 g DM/m² of canopy area). This average tree had a DBH of 26 cm and a canopy area of 81 m². Low and highly variable fruit yields appear to constrain enhanced use of these species here. These species warrant further attention in research and development, however, given their strategic value as forage resources in pastoral systems and their ability to persist in variable environments.     

Sap flow characteristics of three afforestation species during the wet and dry seasons in a dry-hot valley in Southwest China

Assessing and using tree species (exotic or native) with superior tolerance to environmental stresses (such as drought and high temperature) play an important role in afforestation practices. In the present study, stem sap flow characteristics and responses to ambient meteorological factors of three tree species, Albizzia kalkora (native), Azadirachta indica (exotic), and Acacia auriculaeformis (exotic), in a dry-hot valley (Yuanmou, Yunnan Province, China) were investigated using thermal dissipation probes. The diurnal dynamics of sap flow in three studied species displayed an obvious circadian rhythm during the wet and dry seasons, with the exception of A. indica during the dry season. The sap flow velocity (SFV) in A. kalkora and A. auriculaeformis was significantly positively correlated with photosynthetically active radiation (PAR), air temperature, vapour pressure deficit (VPD) and wind speed, but negatively correlated with atmospheric relative humidity over the two seasons. The cross-correlation analysis also revealed that the SFV of the three species was significantly correlated with PAR and VPD (P < 0.001). Additionally, stem sap flow lagged behind PAR but ahead of VPD, and the diurnal sap flow was more dependent on PAR than on VPD. However, we found that the dominant climatic factor influencing the stem sap flow differed between daytime and nighttime. PAR was more influential than other meteorological factors during the daytime, while VPD or other factors were more influential overnight. When the nighttime refilling ability of the three tree species was compared, our results suggest that A. indica has higher drought resistance and better for afforestation of the studied region.     

Chemical composition,in vitro dry matter digestibility and in sacco degradability of selected browse species used as animal feeds under semi-arid conditions in Northern Ethiopia

The study was conducted in Abergelle district of Tigray, northern Ethiopia with the objectives of evaluating the chemical composition, in vitro dry matter digestibility (IVDMD) and in sacco degradability characteristics of foliages of major browse species. Samples of foliages from 12 and 10 browse species were collected during the wet and dry seasons, respectively. The samples of the browse species were collected based on their abundance in the district, preference by livestock to browse them, accessibility to browsing and their additional uses other than livestock feed. The neutral detergent fiber (NDF) was higher in the browse species during the wet compared to the dry season except for Sterculia africana and Ziziphus spina-christi. Similar trends were observed for acid detergent fiber (ADF) content except for Acacia asak. The condensed tannins content and the IVDMD of the browse species had inverse relationships in both seasons. The in sacco dry matter (DM) and nitrogen degradability parameters of the browse species were seasonally variable. Based on in sacco potential DM and nitrogen degradation of the browse species in both seasons, Acacia oerfota, Acacia tortilis, Balanites aegyptiaca, Boswellia papyrifera, Sterculia africana, Terminalia brownii and Ziziphus spina-christi were ranked to be superior in their nutritive value, and thus can have better use as animal feeds. Consequently, these browse species could be considered in agro-forestry systems for better integration of livestock production with available feed resources in semi-arid areas.     

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]     

云南干热河谷4种植物抗旱机理的研究

通过干旱胁迫试验,对云南干热河谷4种植物的抗旱机理进行了研究。选用与植物抗旱性关系密切的8个生理生化测定指标:叶片相对含水量、相对电导率、MDA、SOD、POD、荧光、叶绿素含量、Pro,运用模糊数学中的隶属函数方法对云南干热河谷的车桑子、清香木两个原生植物和山毛豆、银合欢两个引种植物容器苗的抗旱性能进行了系统地综合评价。从而克服了单项生理生化指标的片面性,使评定结果较客观全面地反映此4种干热河谷植物的抗旱机理。