Seasonal suitability of three rubber tree clones to Calacarus heveae (Acari, Eriophyidae)

The suitability of rubber tree clones to Calacarus heveae was inferred from the life cycle, reproduction and survivorship of this mite. The assays were performed under controlled conditions with leaflets detached from 6-year-old plants. The development of 20 C. heveae individuals on each of the clones GT 1, PB 235 and RRIM 600 was analysed. This experiment was performed four times during periods when C. heveae was abundant in the field: (P1) November–December 2005, (P2) January–February, (P3) March–April and (P4) May–June 2006. Accordingly, the leaflets used in each assay represented the physiological condition of the host plant during each period. This approach allowed us to evaluate the seasonal suitability of rubber tree clones to C. heveae. We observed seasonal differences in the suitability of rubber tree clones to mite attack. The mites reared on the PB235 had a shorter development period, the highest egg production and highest survivorship. This evidence showed that the PB 235 was the most suitable of those tested. We also observed that the leaflets used in the assays during periods P2 and P3 were the most favourable for the development of C. heveae. This finding emphasises the seasonal suitability of rubber tree leaflets. On the other hand, GT 1 showed higher resistance against C. heveae than did RRIM 600 and PB 235, primarily during the period from November to February. This result indicated that use of the GT 1 clone to control the mite might represent an alternative for growers.     

星星草耐盐碱生理机制再探讨

用不同浓度Na2CO3处理星星草幼苗,7d后测定叶片相对电导率、渗透势、光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、蒸腾强度（Tr）、水分利用效率（WUE）等生理指标,以研究星星草抗盐碱的生理机制。结果表明,低浓度Na2CO3胁迫下,星星草幼苗可通过渗透调节来减轻细胞所受的伤害,因而膜透性受影响较小,相对电导率上升较少,而Gs基本保持不变,Pn、Tr还有所促进,WUE有所增加,这些结果说明,星星草幼苗对低浓度碱性盐具有一定抗性;但犀星草幼苗的这种抗性有一定限度,随着Na2CO3胁迫浓度的增加,Gs、Tr、Pn依次受到抑制,最终膜透性急剧增加,说明星星草幼苗已受损严重,这些变化具有较强的顺序性。     

中国北方杂草稻光合与水分生理特性

杂草稻是一类重要的稻属种质资源,具有耐寒、耐旱、耐瘠薄等优良特性.本文以88份中国北方杂草稻资源和4份栽培稻为材料,研究了中国北方杂草稻的光合速率、蒸腾速率、气孔导度等光合与水分生理特性及其相互关系.结果表明: 北方杂草稻资源的光合和水分生理特性存在较大差异,具有丰富的多样性.杂草稻的光合速率变化范围在12.47～28.67 μmol CO₂·m^-2·s^-1,瞬时水分利用效率的变化范围在1.39～3.40 mg·g^-1.光合参数中,胞间CO₂浓度的变异系数最小,气孔导度的变异系数最大.光合速率与蒸腾速率、气孔导度呈极显著的二次曲线关系,光合速率与胞间CO₂浓度呈显著的直线关系,瞬时水分利用效率与蒸腾速率、气孔导度呈极显著的二次曲线关系.可用杂草稻材料的优越性能对栽培稻进行品种改良.     

不同浇水量对毛乌素沙地沙柳幼苗气体交换过程及其光化学效率的影响

 利用毛乌素沙地优势灌木沙柳(Salix psammophila)幼苗,研究气体交换及其PSⅡ的光化学效率对4种浇水量响应。结果表明：不同浇水量明显影响沙柳幼苗净光合速率、蒸腾速率、气孔导度、胞间CO2浓度和叶片温度日变化动态;除幼苗叶片温度随着浇水量的增加而降低外,其它以上因素均随浇水量的增加而增大。浇水量少时,幼苗净光合速率明显有“午睡”现象,而充足浇水能有效消除幼苗净光合速率的“午睡”现象;浇水量增加降低了沙柳幼苗光补偿点,提高了饱和光强和表观量子效率;浇水量显著影响幼苗的PSⅡ光化学效率,随着浇水量减少,幼苗的最大荧光、可变荧光、最大荧光比和最大光化学效率逐渐减小。相关分析反映了在不同施水量处理下,环境因子光合有效辐射、大气温度、大气饱和水汽压差及其生理变量气孔导度、叶片温度、胞间CO2浓度均显著影响幼苗净光合速率。     

Response of Seedlings of Three Dominant Shrubs to Climate Warming in Ordos Plateau

Ordas plateau is a classical semi-dry sandland in China. The dry ecosystem responds sensitively to water-heat pattern of global change there. The distribution pattern and productivity of terrestrial ecosystem are greatly affected by global warming. Ecological adaptation strategies of seedlings of Caragana　intermedia Kuang et H. C. Fu, Hedysarum mongolicum Turcz. and Artemisia ordosica Kraschen.,three dominant shrubs in Ordas plateau, were investigated in terms of morphological plasticities, biomass effects and photosynthetic and physiological characters, to the global warming by artificially controlling two temperature levels. The results show that the effects of temperature enhancement on growth and photosynthetic and physiological characters were obviously different among these three plant species. Temperature enhancement significantly increased tree height, leaf number, leaf area, biomass, photosynthetic rate, transpiration rate and stomatal conductance of C. intermedia and H. mongolicum seedlings, indicating that elevated temperature significantly affected the growth of these seedlings positively. Elevated temperature had almost no significant effect on the growth of A. ordosica seedlings. Their leaf number, leaf size, leaf area, biomass, transpiration rate and stomatal conductance did not increase obviously, but tree height and photosynthetic rate obviously increased with increasing temperature. Interspecific growth was significantly different among C. intermedia, H. mongolicum and A. ordosica seedlings. Except leaf size, values of the other seven characters of C. intermedia seedlings were greater than those of H. mongolicum and A. ordosica seedlings.     

土壤水分变化对长白山主要树种蒙古栎幼树生长的影响

选择长白山红松阔叶林主要优势树种蒙古栎为研究对象,人工控制3种施水量研究蒙古栎幼树形态、生物量效应和光合生理特征对土壤含水量变化的响应．结果表明,不同土壤含水量变化显著影响蒙古栎叶片、枝、根的生物量及其分配格局和叶片光合气体交换特征．水分胁迫改变幼树树冠结构,抑制幼树树高、地径、叶片大小、地上和地下生物量;同时,蒙古栎幼树根冠生物量比随着土壤水分含量的减少显著提高;供水量减少对幼树净光合速率、CO2利用率和碳利用率等特征有显著的负向影响;而叶片气孔导度、蒸腾速率和水分利用率对不同土壤含水量反应较复杂,只在土壤含水量较低时,幼树气孔导度、蒸腾速率明显降低,叶片水分利用率升高,表现出蒙古栎树种是干旱可变植物,长期水分胁迫可提高树种的耐旱能力．     

Stomatal limitation of photosynthesis as affected by water stress and CO2 concentration

A water stress effect on photosynthesis and transpiration of wheat seedlings at 50-500 µmol(CO2) mol-1 was measured in an open gas exchange system. The limitation of photosynthesis by stomatal conductance was quantified by a stomatal control coefficient of the net photosynthetic rate. The stomatal control coefficient increased linearly as the water potential of root media decreased to -1 MPa, and it decreased with increasing CO2 concentration.     

楸树无性系光合特性研究

以10个楸树无性系为试验材料,利用Li-6400光合测定仪对其光合特性进行了比较研究。结果表明:楸树净光合速率(Pn)日变化为典型的双峰曲线,气孔限制是光合"午休"的主要调节因素。楸树所有无性系光合作用对光照强度(PAR)单一生态因子水平的响应均可以用二次方程描述。楸树的光补偿点(LCP,11.37~57.4μmol.m-2.s-1)和CO2补偿点(CCP,57.73~77.06μmol.mol-1)在10个无性系间存在显著差异。10个楸树无性系的净光合速率、气孔导度、蒸腾速率和瞬时水分利用效率在无性系间存在极显著差异。在光饱和点(LSP)条件下,10个无性系净光合速率处于18.8~24.4μmol.m-2.s-1之间。环境因子与光合指标存在显著的相关关系,PAR和空气湿度(RH)对楸树无性系瞬时Pn影响最大。     

Spatial distribution of Tenuipalpus heveae Baker (Acari: Tenuipalpidae) on rubber tree plantations

The objective of this work was to study the spatial distribution of Tenuipalpus heveae Baker in rubber tree plantations. The experimental area was located in Marinópolis, State of S?o Paulo, and corresponded to a total of 1,000 plants (clone RRIM 600) divided in 100 plots of ten plants each. A total of 16 samplings were conducted, approximately once every 10 days, between December 2007 and June 2008. On each date, samples were taken from two plants per plot, each sample corresponding to the top 30 cm of a branch randomly taken from the median region of the canopy of each plant. The number of T. heveae was evaluated on three leaflets randomly taken from each sample, using a 20x power pocket magnifying glass. The number of mites was evaluated in two areas of 1 cm2 delimited on the lower surface of each leaflet, being one along the midrib and the other along a lateral vein. The calculated dispersion indexes were: variance/mean relationship (I), index of Morisita (I′), coefficient of Green (Cx) and k exponent of negative binomial distribution. Tenuipalpus heveae showed aggregate distribution. The negative binomial distribution model was the most appropriate to represent the spatial distribution of the mite in the rubber tree plantation.     

不同栽培基质下碧玉兰光合指标日变化研究

探讨5种不同栽培基质对碧玉兰光合指标日变化的影响。结果表明：5种基质栽培的碧玉兰,其净光合速率、蒸腾速率、胞间CO₂浓度及气孔导度的日变化趋势基本呈“双峰”曲线。在基质Ⅳ（1/4树皮+1/4泥炭+1/4水苔+1/4陶粒）中栽培的碧玉兰净光合速率、胞间CO₂浓度及气孔导度变化值相对较大,其次是基质Ⅲ（1/2树皮+1/4泥炭+1/4水苔）,两者与对照差异显著（p<0.05）。综合来看,基质Ⅳ最适宜碧玉兰的生长。     

模拟大气硫酸铵污染对香樟幼苗生长及光合特性的影响

通过室内盆栽实验研究了大气颗粒污染物硫酸铵对香樟幼苗生长及光合特性的影响。结果表明,香樟幼苗叶片涂抹硫酸铵处理对植物生长无显著影响;低浓度硫酸铵(2 g·L^-1)提高了叶片叶绿素含量,而高浓度(4 g·L^-1)却降低了叶片叶绿素含量;与对照相比,低浓度处理的香樟叶片净光合速率、气孔导度、胞间二氧化碳浓度与蒸腾速率无显著差异;高浓度处理的香樟叶片净光合速率与蒸腾速率高于对照,而气孔导度与胞间二氧化碳浓度与对照无显著差异。机理分析表明,硫酸铵颗粒物主要通过影响叶片气孔导度来影响植物光合特性。     

干旱胁迫下杨树无性系苗期光合与气孔形态变异研究

为了解不同干旱胁迫处理下,杨树叶片光合特性和气孔形态的变化规律,本研究以4个杨树无性系为材料,对其干旱胁迫下光合指标与气孔形态指标进行测定分析,方差分析结果表明：除气孔器长在处理间差异不显著外,其他性状在无性系间、处理间和无性系与处理交互作用间均达极显著差异水平。随着土壤相对含水量的逐渐降低,无性系净光合速率、蒸腾速率和气孔导度都呈现出不同程度的下降;而胞间二氧化碳浓度呈现为先降后升趋势,表明当土壤相对含水量大于40%时,光合作用的主要限制因子是气孔因素,当土壤相对含水量低于40%时,光合作用的主要限制因子转换为非气孔因素。气孔形态研究结果表明,各指标均随土壤相对含水量的持续降低呈现出持续下降趋势。利用隶属函数法对不同干旱胁迫下4个杨树无性系的抗旱性进行综合评价,结果表明：白城小青黑杨的抗旱性优于其他三个无性系。     

低N胁迫下巴西橡胶实生苗叶片SPAD值、N素营养及农艺性状的变化

对3个品种(GT1、RRIM600、PR107)巴西橡胶(Hevea brasiliensis)实生苗进行不同N素(0%N,50%N,100%N)处理,分析比较叶片SPAD值、N素营养和农艺性状的变化及其关系。结果表明:(1)缺N胁迫明显降低了叶片SPAD值、叶片N含量和硝酸还原酶活性,缩小了叶蓬距、叶面积,且影响幅度随胁迫强度的加大而增大;(2)不同品种橡胶树实生苗对缺N胁迫的响应程度不同,总体上GT1较为敏感,PR107次之,RRIM600较不敏感;(3)橡胶树实生苗叶片SPAD值、叶蓬距、叶面积与叶片N含量、硝酸还原酶活性之间均呈显著或极显著正相关。因此,有可能采用测定叶片SPAD值、叶蓬距和叶面积等简易方法判断橡胶树新生叶蓬的N素营养状况。     

沙埋对沙米幼苗生长、存活及光合蒸腾特性的影响

沙米(Agriophyllum squarrosum)是藜科沙蓬属1年生沙生植物,广泛分布于我国各主要沙漠和沙地中。为了解沙埋对沙米生长、存活和光合蒸腾特性影响,2010-2011年在科尔沁沙地研究了不同沙埋深度下沙米幼苗高度、存活率、光合速率、蒸腾速率、气孔导度和水分利用效率的变化,结果表明:沙米具有极强的耐沙埋能力。埋深为株高25%时,沙米幼苗存活率和株高显著增加,埋深为株高50%-100%时,其株高和存活率虽有下降,但与非沙埋对照差异不显著。当沙埋深度超过株高后,其株高和存活率急剧下降,但沙埋达到株高266%时仍然有部分幼苗存活。沙埋第5天,随着沙埋深度的增加,沙米幼苗的光合速率缓慢下降,蒸腾速率、气孔导度和水分利用效率均呈波动式变化。随着沙埋时间的延长,和对照相比,沙米幼苗的光合速率、蒸腾速率和气孔导度均随沙埋深度增加而大幅度下降,但水分利用效率仍呈波动式变化。沙埋第15天时其光合速率、蒸腾速率、气孔导度和水分利用效率分别较非沙埋对照下降了86.7%、89.0%、90.0%和4.2%。相关分析表明,沙米幼苗的存活率和高生长与其光合速率、蒸腾速率、气孔导度变化呈显著正相关,而其光合速率、蒸腾速率、气孔导度之间也呈显著正相关,但与水分利用效率的相关性未达到显著水平。沙埋胁迫下沙米幼苗存活率下降和生长抑制不仅源于沙埋造成幼苗顶土困难和光合面积减少,光合速率、蒸腾速率和气孔导度下降也是重要原因。     

NaCl胁迫对沙棘和银水牛果幼苗生长及光合特性的影响

以沙棘和银水牛果2年生幼苗为试材,设NaCl浓度分别为0、200、400和600 mmol·L^-1,研究NaCl 胁迫对其生长及光合特性的影响.结果表明: 随着NaCl浓度的增加,沙棘和银水牛果幼苗的生物量、单株总叶面积均显著下降,且NaCl浓度越高, 下降幅度越大.不同NaCl浓度处理下,沙棘和银水牛果幼苗根冠比较对照显著增加,比叶质量(LMA)略有降低.随着NaCl浓度的增加和胁迫时间的延长,沙棘和银水牛果叶片净光合速率(P_n)、蒸腾速率(T_r)和气孔导度(G_s)均明显下降, 胞间CO₂浓度(C_i)先降后升,气孔限制值(L_s)和水分利用效率(WUE)则先升后降.P_n下降的原因短期内以气孔限制为主,长期则以非气孔限制因素为主,且树种耐盐性越弱,NaCl浓度越高,由气孔限制转为非气孔限制的时间越早.试验中,沙棘幼苗在600 mmol·L^-1NaCl处理10 d时即出现盐害症状,22 d时全部死亡,而银水牛果可以忍耐600 mmol·L^-1NaCl长达30 d以上,说明银水牛果作为引进树种,其耐盐性较沙棘更强,可能更适合在我国盐碱地大面积推广种植.     

云南保存橡胶树魏克汉种质资源亲子系谱分析

对“农业部景洪橡胶树种质资源圃”（云南景洪）保存的290份魏克汉种质资源进行了亲子系谱分析。结果表明,无性系GT1、PR107、PB86、RRIM600、云研277-5、PB5/51、IAN873的后代为210份,占72.41%。从表型看,魏克汉种质资源群体变异丰富,实际上遗传基础很窄。本文以GT1、PR107、PB86、RRIM600、云研277-5、PB5/51、IAN873为主线建立了亲子系谱图,并对部分种质资源的性状进行了分析,获得一些性状的传递遗传规律,供育种工作者参考。     

遮光处理对西葫芦幼苗形态特征及光合生理特性的影响

研究了不同遮光处理对西葫芦幼苗形态及光合生理特性的影响.结果表明,在60%透光率条件下,西葫芦幼苗具有较高的相对生长率、净光合速率、气孔导度、蒸腾速率、单叶水分利用效率、饱和蒸汽压、表观量子效率和叶绿素含量,而胞间CO₂浓度较低;西葫芦幼苗具有较高的光饱和点(1 125 μmol·m^-2·s^-1)、较低的光补偿点(15.2 μmol·m^-2·s^-1).弱光下西葫芦幼苗较耐低浓度CO₂,而强光下的幼苗较耐高浓度CO₂.60%透光率下西葫芦幼苗叶片丙二醛和脯氨酸含量最低,而过氧化物酶和过氧化氢酶活性则最高.     

Elevated CO2 induces physiological, biochemical and structural changes in leaves of Arabidopsis thaliana

Leaves of Arabidopsis thaliana grown under elevated or ambient CO2 (700 or 370 micromol mol(-1), respectively) were examined for physiological, biochemical and structural changes. Stomatal characters, carbohydrate and mineral nutrient concentrations, leaf ultrastructure and plant hormone content were investigated using atomic absorption spectrophotometry, transmission electron microscopy and enzyme-linked immunosorbent assay (ELISA). Elevated CO2 reduced the stomatal density and stomatal index of leaves, and also reduced stomatal conductance and transpiration rate. Elevated CO2 increased chloroplast number, width and profile area, and starch grain size and number, but reduced the number of grana thylakoid membranes. Under elevated CO2, the concentrations of carbohydrates and plant hormones, with the exception of abscisic acid, increased whereas mineral nutrient concentrations declined. These results suggest that the changes in chloroplast ultrastructure may primarily be a consequence of increased starch accumulation. Accelerated A. thaliana growth and development in elevated CO2 could in part be attributed to increased foliar concentrations of plant hormones. The reductions in mineral nutrient concentrations may be a result of dilution by increased concentrations of carbohydrates and also of decreases in stomatal conductance and transpiration rate.     

不同施水量处理下樟子松幼苗叶片水分生理生态特性的研究

研究了在不同水分处理下樟子松幼苗的若干生理生态过程和抗旱机制。结果表明,樟子松幼苗的净光合速率、蒸腾速率、气孔导度、水分利用效率、叶片温度及其他水分指标均随施水量的不同呈现较规律的变化;409．2和189．2mm施水量对樟子松幼苗各项指标的影响呈显著差异,而409．2和321．2mm之间与321．2和189．2mm之间均无差异;樟子松幼苗抗旱机制以抗脱水为主。