干旱-高温交叉胁迫对水稻幼苗光合特性的影响

以水稻品种‘N22’为试材，设置水稻幼苗正常生长（CK）、单一高温处理（H）以及干旱-高温交叉处理（DH）的水培试验，测定其叶片叶绿素含量、光合参数及叶绿素荧光参数，观察表皮气孔和叶肉细胞形态、叶绿体结构。结果表明，与CK相比，H处理水稻幼苗的叶绿素a、b含量、净光合速率（P_n）、气孔导度（G_s）、胞间CO₂浓度（C_i）、蒸腾速率（T_r）和实际光能转化效率[Y（Ⅱ）]显著降低，下降的幅度分别为82.15%、66.82%、64.83%、8.23%、66.20%和27.51%。DH处理下水稻幼苗叶绿素a、b含量、P_n、G_s、C_i、T_r及Y（Ⅱ）与CK差异不显著，而显著高于H处理，分别是H处理下的4.35、2.67、3.20、1.17、3.46和1.23倍。干旱预处理的水稻幼苗，通过维持正常的叶绿素含量、稳定的叶肉细胞及叶绿体结构和适度的气孔开度，可在一定程度上缓解后期高温胁迫对水稻幼苗光合作用的...     

干旱胁迫对春小麦旗叶生理特征及其根系抗旱基因表达特征的影响

研究干旱胁迫对春小麦品种旗叶生理特征及其根系抗旱基因表达的影响,对春小麦抗逆栽培和新品种选育具有重要意义。在大兴安岭西麓旱作区,以抗旱组及水敏感组春小麦品种为供试材料,进行干旱（旱棚防雨）和对照（调控补水）2种水分控制处理,分析干旱胁迫下不同春小麦品种旗叶光合指标、生理指标及根系抗旱基因表达差异。结果表明,干旱与对照处理间春小麦旗叶光合特性、生理特征及根系抗旱基因表达等指标均存在显著差异（P<0.05）;干旱胁迫下春小麦旗叶SPAD、净光合速率（P_n）、蒸腾速率（T_r）、气孔导度（G_s）显著降低,且抗旱组下降幅度显著低于水敏感组;而生理指标过氧化物酶（POD）、超氧化物歧化酶（SOD）、脯氨酸（Pro）均显著升高,丙二醛（MDA）显著降低;其中抗旱组中Pro含量为90.36μg·g^-1,显著高于水敏感组(70.36μg·g^-1),MDA含量(19.82μmol·g^-1)显著低于水敏感组(22.05μmol·g^-1)。TaXTH-...     

2,4-表油菜素内酯对干旱胁迫下垂丝海棠生理特性的影响

以7～8叶龄的垂丝海棠实生苗为试验材料,研究外源喷施2,4-表油菜素内酯（EBR）对干旱胁迫下垂丝海棠幼苗光合及生理特性的影响。采用盆栽控水法,设置CK（正常水分）与干旱胁迫加6种浓度油菜素内酯处理,即T1(0 mg·L^-1)、T2(0.20 mg·L^-1)、T3(0.40 mg·L^-1)、T4(0.60 mg·L^-1)、T5(0.80 mg·L^-1)和T6(1.00 mg·L^-1),分别测定各处理下叶绿素含量、光合特性、抗氧化酶活性及渗透调节物质含量,并进行相关性与主成分分析。随干旱胁迫时间的延长,垂丝海棠叶片的Chl a、Chl b、Chl a+b、Chl a/b、净光合速率（P_n）、气孔导度（G_s）和蒸腾速率（T_r）均呈下降趋势;胞间CO₂浓度（C_i）、丙二醛（MDA）含量和相对电导率（REC）呈上升趋势;脯氨酸（Pro）含量、超氧化物歧化酶...     

不同盐分梯度下胡杨幼苗的光合-光响应特征

通过分析不同盐分处理60 d胡杨幼苗的光响应特征。结果表明：① 在0~3 500 μmol•m^-2•s^-1光强范围,各处理幼苗的净光合速率(P _n)、气孔导度(G_s)、蒸腾速率(T_r)和水分利用效率(WUE)[WTBZ]均随光强增加逐渐增大,而胞间CO₂浓度(C_i)呈相反趋势;不同光强下幼苗的P _n、G_s、T_r、C_i 和WUE均[值均随盐浓度增大而减小;低盐浓度处理(0.5 mol•L^-1)条件下,幼苗通过气孔调节提高WUE,降低盐分对幼苗的损伤;高盐处理(2 mol•L^-1),气孔基本失去调节能力,出现了Tr相对较低、WUE相对较高的现象,而幼苗的Pn[WTBZ]均值降低了约75%,幼苗的光合代谢受到严重抑制。② 随盐浓度增大,胡杨幼苗的最大净光合速率(Pnmax)、表观量子效率(α)、暗呼吸速率(Rd)和光饱和点(LSP)逐渐降低,光补偿点(LCP)逐渐增加,盐分抑制了幼苗对光的吸收、利用和转换能力。     

7个平欧杂交榛子品种的生理解剖特性及其抗寒性研究

为了解榛子对低温胁迫的生理响应机制,筛选甘肃高寒地区适宜种植的抗寒性品种,以辽宁省经济林研究所引进的7个榛子品种的休眠期枝条和叶片为试验材料,分别对其进行低温处理,测定其光合以及相关生理指标,同时采用石蜡切片观察不同品种叶片的显微结构,并用主成分分析综合评价各品种的抗寒性强弱。结果表明：(1)不同时期品种达维的P_n最高,分别为20.7(7月)、11.8(8月)、8.7(9月)μmol·m^-2·s^-1;辽榛8号的G_s在7月和9月出现最低值,分别为0.11 mmol·m^-2·s^-1(7月)和0.06 mmol·m^-2·s^-1(9月),而8月辽榛3号的G_s最低,为0.133 mmol·m^-2·s^-1;9月品种辽榛9号的C_i达到最高值,为334.33μmol·mol^-1;品种玉坠的T_r在9月...     

云杉矮槲寄生的侵染对青杄光合与蒸腾作用的影响

 云杉矮槲寄生(Arceuthobium sichuanense)属半寄生性多年生种子植物,是青海省云杉天然林毁灭性生物灾害之一。本研究首次报道了云杉矮槲寄生在自然条件下可以侵染青杄,并对健康与染病青杄(Picea wilsonii)针叶形态及其光合日变化进行了测定。结果表明:1)染病青杄的针叶长度和宽度显著小于健康青杄(P＜0.001),而染病青杄的针叶比叶面积(SLA)显著大于健康青杄(P＜0.001);2)云杉矮槲寄生的侵染显著降低了青杄叶片的净光合速率、蒸腾速率以及气孔导度(P＜0.05),但不影响其胞间CO₂浓度(P =0.32);3)冗余分析(RDA)表明,云杉矮槲寄生的侵染导致青杄对不同环境因子的依赖程度发生变化,健康青杄表现为环境CO₂浓度(CO₂)＞空气温度(T_air)＞叶片温度(T_l)＞蒸汽压亏缺(Vpd)＞空气相对湿度(RH)＞光合有效辐射(PAR),而染病青杄则出现T_l＞RH＞T_air＞PAR＞Vpd＞CO₂,且T_l成为影响染病青杄叶片光合与蒸腾作用(P_n、T_r)的主要环境因子,且染病青杄对RH和PAR变化的响应更加敏感。此外,染病青杄叶片的水分利用率(WUE)显著低于健康寄主(P＜0.05)。因此,云杉矮槲寄生的侵染可降低青杄对环境的适应能力,从而加速寄主的衰老死亡。     

不同秸秆覆盖耕种模式对半干旱区玉米生长发育及水分利用的影响

研究合理的秸秆覆盖耕种模式是实现半干旱区秸秆覆盖条件下玉米绿色高效生产的重要途径。开展2 a大田试验,设置传统耕作模式(CK)、秸秆覆盖模式(T1)、秸秆覆盖+深松模式(T2)、秸秆覆盖+碎混模式(T3)4个处理,研究不同秸秆覆盖耕种模式对玉米根系伤流特性、光合特性、碳氮代谢相关酶活性、生长发育、产量及其构成因素和水分利用特性的影响。结果表明：不同处理玉米根系伤流强度、伤流液中细胞分裂素(CTK)和生长素(IAA)含量均表现为T3>T2>CK>T1,脱落酸(ABA)含量表现为T1>CK>T2>T3;与CK和T1处理相比,T2与T3处理的CTK和IAA含量显著增加、ABA含量显著下降。玉米叶片净光合速率(P_n)、气孔导度(G_s)、胞间二氧化碳浓度(C_i)、蒸腾速率(T_r)、表观叶肉导度(AMC)和叶片水分利用效率(WUEL)均表现为T3>T2>CK>T1,气孔限制百分率(L_s)表现为T3相似文献   

NaCl胁迫下不同葡萄砧木耐盐性与其离子吸收、光合特性的关系

为筛选耐盐葡萄砧木并探究其耐盐机制，以13种1 a生葡萄砧木为试材，研究100 mM NaCl浇灌处理下葡萄砧木的生长量、光合特性及植株体内Na⁺、Cl^-、K⁺、Mg²⁺、Ca²⁺的差异性变化。盐害指数结果表明：110R和101-14盐害指数较小，为高抗盐砧木，Dogridge、5BB和香槟尼为抗盐品种；5C、贝达和B.R.No.2为中抗盐砧木，Valiant和山河2号为盐敏感品种，188-08、3309C和140R盐害指数最大耐盐性最弱，为盐高敏感砧木。生理指标测定结果发现：NaCl胁迫下，砧木5BB、101-14、Valiant、山河2号、Dogridge、5C其茎粗增加量、新梢增加量与对照相比均存在显著性差异；各葡萄砧木净光合速率(P_n)、气孔导度、蒸腾速率(T_r)均显著低于对照组，盐胁迫后期，140R和188-08叶片P_n分别为0.38μmol·m^-2·S^-1和...     

干旱胁迫对大豆光合、产量及品质的影响

以大豆品种陇中黄601、陇中黄602、中品661、晋豆21为材料，设置正常灌水(CK)、中度干旱(D₁)、重度干旱(D₂) 3个水平进行干旱胁迫处理，采用2 a试验分析大豆苗期、开花期和鼓粒期光合生理生态指标以及成熟后农艺性状、产量和品质的差异。结果表明，随着干旱胁迫程度的加重，大豆生长指标、光合指标及产量均呈递减趋势，在重度干旱胁迫(D₂)下，大豆产量降幅最大达到56.7%。D₂处理开花期的P_n降幅最大，达45.15%,苗期的叶绿素SPAD值升高幅度最大，为21.92%。各品质指标均随干旱程度的增加呈上升趋势，D₂处理下，大豆蛋白质和脂肪含量比CK分别增加4.51%和1.77%。不同品种的蛋白质、脂肪、果糖、亚油酸、亚麻酸、油酸、硬脂酸、非必需氨基酸和必需氨基酸含量与产量呈负相关，蔗糖、淀粉多糖和棕榈酸含量与产量呈正相关，说明干旱胁迫下大豆产量和品质的提升仍存在矛盾。早熟品种陇中黄601丰产抗旱，适宜在干旱半干旱区种植。     

克拉玛依人工林俄罗斯杨(Populus russkii)与新疆杨(P. alba var. Pyramidalis)光合特性分析

为研究克拉玛依人工林中俄罗斯杨与新疆杨的光合特性的差异,利用Li-6400便携式光合分析仪,在人工控制环境下,测定了克拉玛依规模化人工林中的两种主要树种(新疆杨和俄罗斯杨)的光合响应曲线、气孔导度、胞间CO2浓度以及蒸腾速率等光合生理特征,并对两种杨树的光合生理特征进行对比分析。通过对比分析知,相同条件下,新疆杨的净光合速率(Pn)比俄罗斯杨大,因此,相同时间下,新疆杨固定的CO2及积累的生物量比俄罗斯杨多,在规模化人工林的碳汇功能中,新疆杨的贡献率要比俄罗斯杨大。但是,新疆杨的耗水量较大,在干旱环境中,这必然成为新疆杨大面积栽培的一个限制因素。该研究可为克拉玛依人工林的两种杨树品种进行合理的配置提供参考依据。     

土壤水分胁迫对紫花苜蓿光合特性及其生物量的影响

紫花苜蓿是我国重要的豆科牧草，具有较强的抗旱能力，而水分亏缺是影响其产量的主要逆境因子之一。通过大田试验对不同水分胁迫下紫花苜蓿的光合特性及产量进行研究，结果表明：① 土壤水分胁迫对紫花苜蓿光响应参数影响显著(P＜0.05)，随着水分胁迫的加剧，最大净光合速率、表观量子效率、光饱和点逐渐降低，暗呼吸速率、光补偿点逐渐升高，从而直接影响紫花苜蓿光合作用对弱光的吸收和转化效率。② 随着水分胁迫的加剧紫花苜蓿叶片的净光合速率(Pn)和蒸腾速率(Tr)呈显著的下降趋势，气孔导度(Gs)呈先下降后上升的趋势，表明轻度水分胁迫下气孔因素是Pn下降的主要因素，中度和重度水分胁迫下非气孔因素是Pn降低的主要因素。③ 当光合有效辐射(PAR)为1 200 μmol·m^-2·s^-1时，轻度水分胁迫的水分利用效率(WUE)显著大于充分灌溉的WUE (P<0.05)，表明适度水分胁迫可提高紫花苜蓿叶片的水分利用效率。④ 轻度水分胁迫与充分灌溉干草产量之间无显著差异，表明轻度水分胁迫能达到高产节水的目的。     

Sap flow characteristics and physiological adjustments of two dominant tree species in pure and mixed plantations in the semi-arid Loess Plateau of China

It is essential to understand the water consumption characteristics and physiological adjustments of tree species under drought conditions, as well as the effects of pure and mixed plantations on these characteristics in semi-arid regions. In this study, the normalized sap flow (SF_n), leaf water potential, stomatal conductance (g_s), and photosynthetic rate (P_r) were monitored for two dominant species, i.e., Pinus tabuliformis and Hippophae rhamnoides, in both pure and mixed plantations in a semi-arid region of Chinese Loess Plateau. A threshold-delay model showed that the lower rainfall thresholds (R^L) for P. tabuliformis and H. rhamnoides in pure plantations were 9.6 and 11.0 mm, respectively, and the time lags (τ) after rainfall were 1.15 and 1.76 d for corresponding species, respectively. The results indicated that P. tabuliformis was more sensitive to rainfall pulse than H. rhamnoides. In addition, strong stomatal control allowed P. tabuliformis to experience low g_s and P_r in response to drought, while maintaining a high midday leaf water potential (Ψ_m). However, H. rhamnoides maintained high g_s and P_r at a low Ψ_m expense. Therefore, P. tabuliformis and H. rhamnoides can be considered as isohydric and anisohydric species, respectively. In mixed plantation, the values of R^L for P. tabuliformis and H. rhamnoides were 6.5 and 8.9 mm, respectively; and the values of τ were 0.86 and 1.61 d for corresponding species, respectively, which implied that mixed afforestation enhanced the rainfall pulse sensitivity for both two species, especially for P. tabuliformis. In addition, mixed afforestation significantly reduced SF_n, g_s, and P_r for P. tabuliformis (P<0.05), while maintaining a high leaf water potential status. However, no significant effect of mixed afforestation of H. rhamnoides was observed at the expense of leaf water potential status in response to drought. Although inconsistent physiological responses were adopted by these species, the altered water consumption characteristics, especially for P. tabuliformis indicated that the mixed afforestation requires further investigation.     

Severe drought strongly reduces water use and its recovery ability of mature Mongolian Scots pine (Pinus sylvestris var. mongolica Litv.) in a semi-arid sandy environment of northern China

Trees growing in a semi-arid sandy environment are often exposed to drought conditions due to seasonal variations in precipitation, low soil water retention and deep groundwater level. However, adaptability and plasticity of individuals to the changing drought conditions greatly vary among tree species. In this study, we estimated water use (T_s) of Mongolian Scots pine (MSP; Pinus sylvestris var. mongolica Litv.) based on sap flux density measurements over four successive years (2013-2016) that exhibited significant fluctuations in precipitation in a semi-arid sandy environment of northern China. The results showed that fluctuations in daily T_s synchronously varied with dry-wet cycles of soil moisture over the study period. The daily ratio of water use to reference evapotranspiration (T_s/ET₀) on sunny days in each year showed a negative linear relationship with the severity of drought in the upper soil layer (0-1 m; P<0.01). The decrease in Ts induced by erratic drought during the growing season recovered due to precipitation. However, this recovery ability failed under prolonged and severe droughts. The T_s/ET₀ ratio significantly declined with the progressive reduction in the groundwater level (g_w) over the study period (P<0.01). We concluded that the upper soil layer contributed the most to the T_s of MSP during the growing season. The severity and duration of droughts in this layer greatly reduced T_s. Nevertheless, g_w determined whether the T_s could completely recover after the alleviation of long-term soil drought. These results provide practical information for optimizing MSP management to stop ongoing degradation in the semi-arid sandy environments.     

Responses of leaf water potential and gas exchange to the precipitation manipulation in two shrubs on the Chinese Loess Plateau

Regulation of leaf gas exchange plays an important role in the survival of trees and shrubs under future climate change. However, the responses of leaf water potential and gas exchange of shrubs in semi-arid areas to the precipitation alteration are not clear. Here, we conducted a manipulated experiment with three levels of precipitation, i.e., a control with ambient precipitation, 50% above ambient precipitation(irrigation treatment), and 50% below ambient precipitation(drought treatment), with two common shrubs, Salix psammophila C. Wang & C. Y. Yang(isohydric plant, maintaining a constant leaf water potential by stomatal regulation) and Caragana korshinskii Kom.(anisohydric plant, having more variable leaf water potential), on the Chinese Loess Plateau in 2014 and 2015. We measured the seasonal variations of predawn and midday leaf water potential(Ψpd and Ψmd), two parameters of gas exchange, i.e., light-saturated assimilation(An) and stomatal conductance(gs), and other foliar and canopy traits. The isohydric S. psammophila had a similar An and a higher gs than the anisohydric C. korshinskii under drought treatment in 2015, inconsistent with the view that photosynthetic capacity of anisohydric plants is higher than isohydric plants under severe drought. The two shrubs differently responded to precipitation manipulation. Ψpd, An and gs were higher under irrigation treatment than control for S. psammophila, and these three variables and Ψmd were significantly higher under irrigation treatment and lower under drought treatment than control for C. korshinskii. Leaf water potential and gas exchange responded to manipulated precipitation more strongly for C. korshinskii than for S. psammophila. However, precipitation manipulation did not alter the sensitivity of leaf gas exchange to vapor-pressure deficit and soil moisture in these two shrubs. Acclimation to long-term changes in soil moisture in these two shrubs was primarily attributed to the changes in leaf or canopy structure rather than leaf gas exchange. These findings will be useful for modeling canopy water-carbon exchange and elucidating the adaptive strategies of these two shrubs to future changes in precipitation.     

Grazing and heat stress protection of native grass by a sand-fixing shrub in the arid lands of northern China

Shrub species are used in restoration projects on dryland for their facilitation effects, which include environmental improvements and protection from herbivore feeding. Facilitation effects on forage grasses are potentially important in improving grazing capacity on rangelands. However, the morphology-dependent performance of benefactor plants in facilitating forage species growth and supplementation under moderate grazing intensity remains unclear. Here, our main purpose was to measure facilitation performance in terms of the survival of a native forage grass, Agropyron cristatum (L.) Gaertn. (Gramineae)., in accordance with the growth conditions of a sand-fixing benefactor shrub, Caragana microphylla Lam., in the Hulun Buir Grassland, northern China. Six study sites with patches of A. cristatum and C. microphylla were established at the foot of fixed sand dunes. At each site, five quadrats were set in places where C. microphylla coverage was 100% and A. cristatum grew among the shrubs (shrub quadrats), and another five were set where A. cristatum grew alone without C. microphylla (grass quadrats). We measured the morphological traits of C. microphylla and A. cristatum in all 60 quadrats, along with the soil water content and soil temperature. The data were compared between the shrub and grass quadrats by generalized linear mixed-effect models to assess the shrub's facilitation effects. We also used such models to elucidate the relationship between the average height of C. microphylla and the morphological traits of A. cristatum in the shrub quadrats. The maximum height, average grazed height, and the number of seed heads of A. cristatum were greater in the shrub quadrats than in the grass quadrats. The soil surface temperature was lower in the shrub quadrats. The maximum height and seed head number of A. cristatum were positively associated with the average height of C. microphylla. These results suggest that the grazing impact and heat stress were smaller in shrub quadrats than in grass quadrats, and that the degree of this protective effect depended on the shrub height. The shrub canopy seemed to reduce the increase in soil temperature and keep the grass vigorous. Livestock likely avoided grazing grasses in the C. microphylla patches because of the shrub's spiny leaves; only the upper parts of the grass stems (including the seed heads) protruding from the shrub canopy were grazed. The sand-fixing shrub thus moderates the grazing impact and soil temperature, and contributes to vegetation restoration and grazing system sustainability.     

Rehabilitation of degraded areas in northeastern Patagonia,Argentina: Effects of environmental conditions and plant functional traits on performance of native woody species

Degradation processes affect a vast area of arid and semi-arid lands around the world and damage the environment and people′s health. Degradation processes are driven by human productive activities that cause direct and indirect effects on natural resources, such as species extinction at regional scale, reduction and elimination of vegetation cover, soil erosion, etc. In this context, ecological rehabilitation is an important tool to recover key aspects of the degraded ecosystem. Rehabilitation trials rely on the use of native plant species with characteristics that allow them to obtain high survival and growth rates. The aim of this work was to assess the survival and growth of native woody species in degraded areas of northeastern Patagonia and relate them to plant functional traits and environmental variables. We observed high early and late survival rates, and growth rates in Prosopis flexuosa DC. var. depressa F.A. Roig and Schinus johnstonii F.A. Barkley, and low values in Condalia microphylla Cav. and Geoffroea decorticans (Gillies ex Hook. & Arn.) Burkart. Early survival rates were positively associated with specific leaf area (SLA) and precipitation, but negatively associated with wood density, the maximum mean temperature of the warmest month and the minimum mean temperature of the coldest month. Late survival rates were positively associated with SLA and soil organic matter, but negatively associated with plant height and precipitation. The temperature had a positive effect on late survival rates once the plants overcame the critical period of the first summer after they were transplanted to the field. Prosopis flexuosa and S. johnstonii were the most successful species in our study. This could be due to their functional traits that allow these species to acclimatize to the local environment. Further research should focus on C. microphylla and G. decorticans to determine how they relate to productive conditions, acclimation to environmental stress, auto-ecology and potential use in ecological rehabilitation trials.     

不同赤眼蜂品系对桃蛀螟卵的寄生功能反应和干扰效应

赤眼蜂是农林业生产中应用最广的一类重要卵寄生性天敌昆虫。为评估其对桃蛀螟卵的寄生潜能，在实验室条件下研究了不同赤眼蜂品系对桃蛀螟卵的功能反应以及自身的干扰反应。结果表明：供试的松毛虫赤眼蜂（TD-SD和TD-XJ）和玉米螟赤眼蜂（TO-SD和TO-JL）对桃蛀螟卵的寄生功能反应均符合Holling Ⅱ型模型，对桃蛀螟卵均有一定寄生能力。其中TD-XJ品系的a/T_h值最大，为19.22，对桃蛀螟卵的寄生能力最强。从功能反应参数的比较中发现，TO-SD、TD-SD、TO-JL和TD-XJ品系赤眼蜂对桃蛀螟卵的寄生上限分别为25.4粒、35.3粒、24.6粒和35.0粒。4个赤眼蜂品系在寄生桃蛀螟卵的过程中均存在自身密度干扰效应。随赤眼蜂密度的增加，其对桃蛀螟卵的寄生率在不断上升，但其对寄主的寻找效应却在不断下降。其中TD-XJ品系对桃蛀螟卵的寻找参数最大，为0.2931。由此可看出，供试的松毛虫赤眼蜂TD-XJ品系对桃蛀螟卵的控制潜能最高。     

2014年海南省橡胶炭疽病菌对多菌灵和咪鲜胺的敏感性测定

 2014年从海南省4个市(县)分离获得43株橡胶炭疽病菌,进行病原菌鉴定后,采用菌丝生长速率法,测定了其对多菌灵和咪鲜胺的敏感性,结果表明:供试菌株中,有23个属于胶孢炭疽病菌,20个属于尖孢炭疽病菌。所有供试菌株对多菌灵和咪鲜胺的EC₅₀值分布范围分别为(0.332 3~7.425 6)和(0.009 1~0.113 3) mg·L^-1,平均值分别为(1.714 1±1.684 7)和(0.036 8±0.023 8)mg·L^-1。其中尖孢炭疽病菌对多菌灵的EC₅₀值要显著高于胶孢炭疽病菌,EC₅₀平均值分别为(2.922 7±1.556 3)和(0.663 2±0.194 4)mg·L^-1,但2种病原菌对咪鲜胺的EC₅₀值没有显著差异,EC₅₀平均值分别为(0.038 3±0.015 2)和(0.035 5±0.020 1)mg·L^-1。供试菌株对多菌灵和咪鲜胺的敏感性无显著相关性,可以在生产上交替使用。     

人参生炭疽菌(Colletotrichum panacicola)和线列炭疽菌(C. lineola)的生物学特性及其对不同杀菌剂的敏感性研究

 近年来,炭疽属真菌(Colletotrichum spp.)引起的人参炭疽病,给人参生产造成了重大经济损失。本文选取分离自我国吉林省栽培人参上的两种炭疽菌人参生炭疽菌(Colletotrichum panacicola)和线列炭疽菌(C. lineola),通过平板培养,测定了它们在不同培养基、温度、碳源、氮源、pH值和光照条件下的生物学特性;采用菌丝生长速率法测定了其对14种杀菌剂的敏感性。结果表明,两种炭疽菌的最适生长温度均为25 ℃,最适生长pH值均为7,光暗交替有利于两种菌的菌丝生长。其中,人参生炭疽菌的菌丝生长最适培养基为V8汁培养基,最适碳源和氮源分别是淀粉和硝酸钾;线列炭疽菌的菌丝生长最适培养基为PDA和PSA培养基,最适碳源和氮源分别是淀粉和硝酸铵;两种炭疽菌对13种药剂敏感,咯菌睛、戊唑醇、抑霉唑、多菌灵、氟环唑、苯醚甲环唑、己唑醇、甲基硫菌灵8种药剂对两种炭疽菌的室内抑菌活性较好,EC₅₀值均小于5.0 μg·mL^-1。咯菌睛、戊唑醇、抑霉唑、多菌灵、氟环唑、苯醚甲环唑、己唑醇、甲基硫菌灵8种药剂对两种炭疽菌的室内抑菌活性较好,EC₅₀值均小于5.0 μg·mL^-1,其中咯菌睛抑菌活性最强,EC₅₀值均小于0.1 μg·mL^-1。两种炭疽菌对同一药剂的敏感性存在差异,线列炭疽菌对吡唑醚菌酯敏感性较高,EC₅₀值小于0.1 μg·mL^-1,而人参生炭疽菌对该药剂的敏感性相对较低(EC₅₀值高于200 μg·mL^-1)。该结果为人参炭疽病发病规律的研究及其田间有效防治奠定了基础。     

Snow resisting capacity of Caragana microphylla and Achnatherum splendens in a typical steppe region of Inner Mongolia,China

Snow resisting capacity of vegetation is important for secondary distribution of water resources in seasonal snow areas of grassland because it affects the regeneration,growth and nutrient circulation of vegetation in grassland.This study investigated vegetation characteristics(canopy height,canopy length and crown width)of Caragana microphylla Lam.(shrub)and Achnatherum splendens(Trin.)Nevski.(herb),and snow morphologies(snow depth,snow width and snow braid length)in a typical steppe region of Inner Mongolia,China in 2017.And the influence of vegetation characteristic on snow resisting capacity(the indices of bottom area of snow and snow volume reflect snow resisting capacity)was analyzed.The results showed that snow morphology depends on vegetation characteristics of shrub and herb.The canopy height was found to have the greatest influence on snow depth and the crown width had the greatest influence on snow width.The canopy length was found to have little influence on morphological parameters of snow.When the windward areas of C.microphylla and A.splendens were within the ranges of 0.0-0.5 m2 and 0.0-8.0 m2,respectively,the variation of snow cover was large;however,beyond these areas,the variation of snow cover became gradually stable.The potential area of snow retardation for a single plant was 1.5-2.5 m2 and the amount of snow resistance was 0.15-0.20 m3.The bottom area of snow and snow volume(i.e.,snow resisting capacity)of clumped C.microphylla and A.splendens was found to be 4 and 25 times that of individual plant,respectively.The results could provide a theoretical basis both for the estimation of snow cover and the establishment of a plant-based technical system for the control of windblown snow in the typical steppe region of Inner Mongolia.