我国常用紫胶虫寄主树产胶质量研究

紫胶虫Kerria chinensis Mahd.寄主树是紫胶生产的物质基础,紫胶质量的优劣,除与胶虫的种类或品系有直接关系外,因害主树种类的不同也有明显的差异。为了选择产胶质量好的寄主树种,对我国紫胶生产上常用的:钝叶黄檀Dalbergia obtusifolia Prain、思茅黄檀Dalbergia szemaoensis Prain、南岭黄檀Dalbergia balansae Prain、大叶千斤拔Flemingia macrophylla(Willd)Merr、马鹿花Pueraria wallichii DC.、久树Schleichera     

信德紫胶虫的引进放养研究

为解决我省所放养的紫胶虫(Kerrialacca)生产的紫胶质量常达不到标准,国内外市场售价比印度产品低的问题,我省于1982年6月从云南省元江县引进了孟加拉国信德紫胶虫(K.sindica),于广州的省林科所及高州县林科所、深镇、根子等地,后又扩大到丰顺、紫金、惠州、梅县等市(县)进行放养试验,现把几年来的试验结果介绍如下。一、寄主植物信德紫胶虫原产地的寄主植物以滇刺枣为主,其次是阿拉伯金合欢、大叶合欢、聚果榕、宝树、久树和雨树。引入我省后,在10余种寄主上放养。信德紫胶虫在聚果榕、滇刺枣、木豆和大叶千斤拔上生长发育良好,可作为生产用树;在南岭黄檀、黄檀、     

绿鳞象甲防治试验

一、前言绿鳞象甲(Hypomeces squamosusHerbst)是鞘翅目、象甲科的一种杂食性食叶害虫。本国紫胶虫七种优良寄主树(秧青、牛肋巴、马榔树、炮火绳、木豆、马鹿花、大叶千斤拔)以及南岭黄檀、金合欢等均受其为害。目前被害较严重的是寄主树滇刺枣。     

几种经济树种水分生理的研究

对在民勤沙区栽培的苹果梨、锦丰梨、金冠苹果、民勤小枣、沙枣５种经济树种的蒸腾强度、组织含水率、自然饱和亏、临界饱和亏、束缚水／自由水、水势、持水力、土壤含水率等８项水分生理指标的测定分析表明，这５种经济树种水分生理指标之间，蒸腾强度与水势呈正相关关系。其中，金冠苹果相关系数达到了０．９５５，呈显著正相关关系；锦丰梨相关系数达到了０．９８９，呈极显著正相关关系；并得出了锦丰梨、金冠苹果的蒸腾强度与其他指标间的多元线性回归方程。     

西昌地区紫胶虫寄主树的繁育与造林

一、我区的主要寄主树我国紫胶虫寄主植物已达284种,分属43科,128属。而西昌地区据现知的寄主植物有74种,分属31科,53属,资源丰富,但栽植普遍、利用广泛的寄主树不多,主要有秧青(思茅黄檀)、牛肋巴(钝叶黄檀)、木豆、黄杞(胖婆娘)和滇黔黄檀等。(一)秧青。别名思茅黄檀。为小至中型乔木。属蝶形花科黄檀属。原分布在云南澜沧江和怒江河谷山坡中,在海拔1400米以下最多,分布高可达海拔1700米。自引入西昌     

中华紫胶虫寄主植物钝叶黄檀研究进展

从紫胶虫优良寄主植物钝叶黄檀研究的目的意义、分布情况与发展利用现状、生物学与生态学研究进展、种质资源研究中存在的问题、现行研究中的问题与对策等几个方面，系统总结了钝叶黄檀的研究现状与热点问题，提出了研究的思路和对策并展望了钝叶黄檀今后的发展方向。     

紫胶虫优良寄主树——钝叶黄檀的生态生物学特性

钝叶黄檀(Dalbergia obtusifoliaprain)是我国紫胶生产上广为利用的优良寄主树。全国的紫胶产量,大多是利用这一树种生产的。钝叶黄檀也是一种速生用材、绿化树种。广西林科所作的材性试验表明:其静     

三种紫胶虫寄主在海南岛的栽培技术

滇刺枣(Ziziphus mauritiana),苏门答腊金合欢(Acacia glauca),大叶千斤拔(Moghania macrophylla)是紫胶虫的优良寄主树。滇刺枣为小乔木,果实可作水果食用,果仁可入中药;苏门答腊金合欢和大叶千斤拔是灌木,既可生产紫胶,同时也可作为薪炭材。这三种树木适生性强,耐干旱贫瘠,生长较快。1984年初我们从云南引进了这三种树种在坝王岭乌烈林场和琼海上蛹区林场进行栽培试验,现将结果整理如下。一、育苗     

紫胶虫优良寄主树—秧青简介

<正> 秧青又名思茅黄檀(Dalbergi Szemaoensis Prain)、紫梗树、亚秧叶树、酸香等,属蝶形花科(Papilion aceae)、黄檀属,是我省由云南引种来的紫胶虫优良寄主树种之一。秧青在云南紫胶老产区是传统常用优良寄主树种之一,适用于冬、夏二代紫胶生产,在云南某些干热年份,它的产胶和保种性能还优于牛肋巴。我省通过多年引种栽培与放养利用,证明秧青具有易繁殖栽培、生长迅速、萌芽力强、耐虫力高、病虫害少、所产紫胶产量高、胶     

紫胶虫优良寄主大叶千斤拔的研究

大叶千斤拔是紫胶虫(Kerria lacca (Kerr).)的优良寄主树之一。1978—1982年的研究结果表明;大叶千斤拔具有生态适应强、繁殖栽培容易、速生、抗旱、耐贫瘠等特性,夏代固虫量以30—40％、冬代以25—30％为适宜。其所产紫胶颜色浅、胶质好,软化点较高,胶被厚,萌发力强,收胶砍伐后的大量萌生枝可再次放养利用。各项指标均优于灌木寄主木豆。     

Rapid response of large, drought-stressed beech trees to irrigation

Large, declining beech (Fagus sylvatica L.) trees (diameter at breast height = 50 cm), growing on heavy clay soils in the highlands near Zurich, Switzerland, were amply irrigated in late summer. During irrigation, the xylem sap flow rate, Q(wt), was measured by the stem-tissue heat balance method with internal heating and sensing. Only a gradual and slight increase in Q(wt) in response to irrigation was observed in the control trees, whereas Q(wt) in the declining trees, whose transpiration rates were only 2-20% those of the control trees, increased 2-5 times within minutes. This suggests, that severe local drought was the major factor limiting tree growth at the site. The extent of the response permits estimation of the supply-limited (soil water) and demand-limited (tree structure) components of stress. Drought caused a decline in Q(wt) in the trees with short crowns and limited root systems that had originally been growing in dense canopies and had become suddenly exposed to full illumination as a result of a severe wind storm and thinning. Trees with deep, narrow, dense crowns, growing in more open places and adapted over a long period to high irradiance remained healthy during drought. Prolonged, periodic water shortage reduced the amount of foliage up to 90% but during drought stimulated the growth of fine roots in the surface and upper soil layers. The stem conductive systems of the declining trees were still partially functional.     

Dynamics of change in stomatal response and water status of Picea abies during a persistent drought period: a contribution to the traditional view of plant water relations

Four experiments on the simulation of a persistent drought period were carried out with cloned Picea abies (L.) Karst. trees: two in the field under varying weather conditions and two in a climate chamber under variously manipulated humidity conditions. Patterns of diurnal dynamics in gas exchange rates and water potential were monitored and analyzed. The first phase of the drought was characterized by relatively high daily maxima for photosynthesis and transpiration. With decreasing humidity during the day, the values dropped steeply, and the declines were larger and occurred earlier on each passing day of the drought period. When soil water potential was lower than -2000 hPa, maximum stomatal aperture was greatly reduced despite a humid atmosphere. Under these conditions, rates of photosynthesis and transpiration decreased less steeply from the daily maxima and differences between maxima and minima were small. In the field, the daily sums of transpiration and photosynthesis were more dependent on atmospheric conditions than on soil water potential. In the growth chamber experiments, the daily sums of transpiration and photosynthesis decreased continuously as the soil dried, at first steeply until a soil water potential of -2000 hPa was reached, then slowly. Predawn water potential values fluctuated under field conditions, but tended to decrease with time, whereas needle osmotic potential increased slightly. Because relative humidities did not reach 100% in the growth chamber, predawn water potentials of plants in the growth chamber were never higher than -1.0 MPa although the soil was saturated. In the experiment with a high average air humidity during the daily stress period, relatively high predawn water potentials were maintained until lower soil water potentials of -8000 hPa were reached. Results were used to assess the importance of evaporative demand versus soil drying on stomatal responses within the context of current concepts of plant water relations. The observed trends in diurnal dynamics can be explained solely by the interdependency of leaf conductance and water potential. Stomata react directly to the ratio of water supply to demand. The central role of peristomatal transpiration in this system is emphasized.     

Mechanisms of drought response in Thuja occidentalis L. II. Post-conditioning water stress and stress relief

We examined the extent of osmotic adjustment and the changes in relative water content (RWC) and transpiration rate (i.e., relative stomatal function) that occur in water-deficit-conditioned 6-year-old Thuja occidentalis L. (eastern white cedar) trees in response to a severe drought. Trees conditioned by successive cycles of mild or moderate nonlethal water stress (conditioning) and nonconditioned trees were exposed to drought (i.e., -2.0 MPa predawn water potential) to determine if water deficit conditioning enhanced tolerance to further drought stress. Following drought, all trees were well watered for 11 days to evaluate how quickly osmotic potential, RWC and transpiration rate returned to preconditioning values. Both nonconditioned trees and mildly conditioned trees exhibited similar responses to drought, whereas moderately conditioned trees maintained higher water potentials and transpiration rates were 38% lower. Both conditioned and nonconditioned trees exhibited a similar degree of osmotic adjustment (-0.39 MPa) in response to drought relative to the well-watered control trees. The well-watered control trees, nonconditioned trees and mildly conditioned trees had similar leaf RWCs that were about 3% lower than those of the moderately conditioned trees. Following the 11-day stress relief, there were no significant differences in osmotic potential between the well-watered control trees and any of the drought-treated trees. Daily transpiration rates and water potential integrals (WPI) of all drought-treated trees approached those of the well-watered control trees during the stress relief period. However, the relationship between cumulative transpiration and WPI showed that previous exposure to drought stress reduced transpiration rates. Leaf RWC of the moderately conditioned trees remained slightly higher than that of the nonconditioned and mildly conditioned trees.     

盐胁迫对国槐和核桃幼苗光合作用的影响

研究了国槐与核桃半年生蛭石盆栽苗在盐 (NaCl溶液处理浓度为 5 0 ,10 0 ,2 0 0mmol·L- 1)胁迫条件下光合作用的变化。结果表明 ,核桃受盐胁迫后净光合速率明显下降 ,并且随盐浓度增大、胁迫时间延长而下降更多。国槐受盐胁迫后净光合速率增加 ,在短时间胁迫下增加多 ,随胁迫时间延长增加幅度变小。国槐与核桃在 2 0 0mmol·L- 1NaCl胁迫 2 4d内叶绿素a和b的含量变化不大 ,但核桃的叶绿素a/b之值下降。并且国槐的类胡萝卜素含量在盐胁迫后先增加后与对照相平 ,而核桃则明显下降。两个树种CO2 响应曲线的主要差别为国槐光呼吸速率下降为对照的4 3 7% ,核桃则比对照增加了 71.6 0 % ;国槐的CO2 补偿点比对照下降了 13.5 8% ,而核桃则比对照上升了 194 .15 %。两个树种在光响应曲线上的差别为国槐的暗呼吸速率比对照增加了 3倍多 ,而核桃则下降为对照的 6 5 .2 8%。核桃发生明显的光抑制     

黄土丘陵区沙棘林几个水分生理生态特征研究

为探讨沙棘对半干旱黄土丘陵区水分条件的适应性,1998年对沙棘的水分生理生态及抗旱性进行了分析研究.试验结果表明(1)沙棘适应半干旱黄土丘陵区生境形成了耐旱、御旱的双重抗旱方式.在旱季,沙棘体内束缚水含量随干旱加剧而上升,束缚水与自由水比值随干旱加剧而增大,叶片维持较高的含水量,蒸腾减弱,叶水势降低,临界饱和亏增大,表现出较强的抗旱性.(2)沙棘光合速率具明显的日变化,1000 1200出现第1次峰值,1400 1500出现第2次峰值.沙棘光合速率与环境因子(气温、相对湿度和光合有效辐射)间有显著的相关关系,相关系数为0.8466 0.9351,其中光合有效辐射对光合速率影响最显著,气温次之,相对湿度最小;沙棘光合速率与气孔导度及细胞间CO2浓度间有十分显著的相关关系,相关系数为0.9852 0.9856.(3)沙棘蒸腾速率与气孔导度具明显的日变化,两者的变化趋势相似,5、7月日变化曲线呈单峰型,6、8、9月日变化曲线呈双峰型.在生长季(5-     

Sap flow rates of Minquartia guianensis in central Amazonia during the prolonged dry season of 2015–2016

Minquartia guianensis Aubl.is a slow-growing species with several uses.In the juvenile state,it is well-adapted to low light conditions of the forest understory.However,it is still unknown how climate variability affects transpiration of this species,particularly under drought stress.In this study,we aimed to assess the effect of climatic variability on sap flow rates(SFR).SFR and radial growth were measured in six trees(14-50 cm diameter) in 2015 and 2016.Climate(precipitation,irradiance,relative humidity and temperature) and soil water content(SWC) data were also collected.SFR tended to increase in the dry season,with a negative relationship between SFR and SWC and precipitation(p 0.001),while there was a positive association between radial growth and monthly precipitation(p=0.004).Irradiance and temperature were the environmental factors more closely correlated with SFR during daytime(p0.001),whereas relative humidity and vapor pressure deficit were the most important factors at night(p0.001).Although negative SFR were sometimes recorded at night,the mean nocturnal sap flow was positive and across trees the nighttime sap flow accounted for 12.5%of the total daily sap flow.Increased transpiration during the dry season suggests that the root system of Minquartia was able to extract water from deep soil layers.These results widen our understanding of the ecophysiology of Amazonian trees under drought and provide further insight into the potential effect of the forecasted decline in precipitation in the Amazon region.     

Growth CO2 concentration modifies the transpiration response of Populus deltoides to drought and vapor pressure deficit

Cottonwood (Populus deltoides Bartr. ex Marsh.) trees grown for 9 months in elevated carbon dioxide concentration ([CO2]) showed significant increases in height, leaf area and basal diameter relative to trees in a near-ambient [CO2] control treatment. Sample trees in the CO2 treatments were subjected to high and low atmospheric vapor pressure deficits (VPD) over a 5-week period at both high and low soil water contents (SWC). During these periods, transpiration rates at both the leaf and canopy levels were calculated based on sap flow measurements and leaf-to-sapwood area ratios. Leaf-level transpiration rates were approximately equivalent across [CO2] treatments when soil water was not limiting. In contrast, during drought stress, canopy-level transpiration rates were approximately equivalent across [CO2] treatments, indicating that leaf-level fluxes during drought stress were reduced in elevated [CO2] by a factor equal to the leaf area ratio of the two canopies. The shift from equivalent leaf-level transpiration to equivalent canopy-level transpiration with increasing drought stress suggests maximum water use rates were controlled primarily by atmospheric demand at high SWC and by soil water availability at low SWC. Changes in VPD had less effect on transpiration than changes in SWC for trees in both CO2 treatments. Transpiration rates of trees in both CO2 treatments reached maximum values at a VPD of about 2.0 kPa at high SWC, but leveled off and decreased slightly in both canopies as VPD increased above this value. At low SWC, increasing VPD from approximately 1.4 to 2.5 kPa caused transpiration rates to decline slightly in the canopies of trees in both treatments, with significant (P = 0.004) decreases occurring in trees in the near-ambient [CO2] treatment. The transpiration responses at high VPD in the presence of high SWC and throughout the low SWC treatment suggest some hydraulic limitations to water use occurred. Comparisons of midday leaf water potentials of trees in both CO2 treatments support this conclusion.     

干旱胁迫对麻栎无性系蒸腾作用的影响

以13个3年生麻栎无性系为研究对象,采用盆栽试验方法,研究了在持续干旱胁迫条件下的麻栎无性系土壤水势、叶片水势光合速率和蒸腾速率变化规律及其关系。结果表明,随着干旱胁迫的加剧,13个麻栎无性系土壤水势呈现出不断下降的变化趋势,叶片水势的变化无一致规律,光合速率则先下降而后上升,蒸腾速率的变化规律不尽相同。在13个麻栎无性系中,2、4、5、7、9和16号无性系的蒸腾速率、叶片水势和光合速率具有相同规律,随着干旱胁迫的加剧先下降而后上升,具有较强的适应干旱逆境的能力。对不同干旱条件下无性系的蒸腾速率、土壤水势、叶片水势和光合速率的相关性分析发现,干旱胁迫7天时,蒸腾速率和光合速率达极显著正相关;干旱胁迫12天时,蒸腾速率和土壤水势间呈极显著负相关,光合速率与土壤水势呈显著负相关;干旱胁迫17天时,蒸腾速率与光合速率呈显著正相关。     

Management of windbreaks in the Sahel: the strategic implications of tree water use

At sites in the Sahel where windbreaks are used to control wind erosion, management strategies are required to minimise competition for water between trees and crops. Uptake of water by windbreak trees was therefore studied in experiments designed to compare water use among tree species, assess which variables exert most control over transpiration and determine the source of water transpired by windbreak trees. Transpiration and soil-water extraction by Acacia nilotica, Acacia holosericea and Azadirachta indica trees in windbreaks were measured at the ICRISAT Sahelian Centre, Niger. Coupling of windbreaks to the atmosphere was evaluated and a stable isotope technique was used to compare utilisation of groundwater by windbreaks and crops at two sites in Niger with different water table levels. Azadirachta indica used least water, probably as a result of lower stomatal conductances, since windbreaks exhibited good physiological control over transpiration. The potential for competition for water was most severe with Acacia nilotica and Acacia holosericea, as they extracted large quantities of water through lateral roots, and at the location where trees could not access groundwater. At such sites, the effects of competition on crop productivity should be minimised by planting tree species with low water requirements and by using pruning to limit tree transpiration.This revised version was published online in November 2005 with corrections to the Cover Date.     

Effects of thinning on soil and tree water relations, transpiration and growth in an oak forest (Quercus petraea (Matt.) Liebl.)

To quantify the effects of crown thinning on the water balance and growth of the stand and to analyze the ecophysiological modifications induced by canopy opening on individual tree water relations, we conducted a thinning experiment in a 43-year-old Quercus petraea stand by removing trees from the upper canopy level. Soil water content, rainfall interception, sap flow, leaf water potential and stomatal conductance were monitored for two seasons following thinning. Seasonal time courses of leaf area index (LAI) and girth increment were also measured. Predawn leaf water potential was significantly higher in trees in the thinned stand than in the closed stand, as a consequence of higher relative extractable water in the soil. The improvement in water availability in the thinned stand resulted from decreases in both interception and transpiration. From Year 1 to Year 2, an increase in transpiration was observed in the thinned stand without any modification in LAI, whereas changes in transpiration in the closed stand were accompanied by variations in LAI. The different behaviors of the closed and open canopies were interpreted in terms of coupling to the atmosphere. Thinning increased inter-tree variability in sap flow density, which was closely related to a leaf area competition index. Stomatal conductance varied little inside the crown and differences in stomatal conductance between the treatments appeared only during a water shortage and affected mainly the closed stand. Thinning enhanced tree growth as a result of a longer growing period due to the absence of summer drought and higher rates of growth. Suppressed and dominant trees benefited more from thinning than trees in the codominant classes.