干旱胁迫下两种岩石边坡修复植物的抗旱性

以岩石边坡常用修复植物火棘和紫穗槐为试材,采用盆栽控水法对其进行干旱胁迫试验,分析干旱胁迫对植物形态和生理的影响。结果表明:在形态特征上,干旱胁迫会使植物发生叶片黄化,植株萎蔫等现象;在生理特征上,随着胁迫时间的增加,火棘、紫穗槐的叶片相对含水量(RWC)、叶绿素含量均呈现不同的下降趋势,相对水分亏缺(RWD)、电导率、丙二醛(MDA)含量、脯氨酸含量和可溶性糖含量均呈现不同程度的上升趋势;干旱胁迫结束时,火棘各生理指标的变化幅度依次为-26.7%、-53.28%、+22.7%、+22.9%,+13.2%、+352.7%和+1.0%;紫穗槐各生理指标的变化幅度依次为-44.3%、-54.8%,+25.3%、+123.6%,+2 327.5%和399.4%。即干旱胁迫对火棘的影响小于紫穗槐,说明火棘的抗旱性高于紫穗槐,在岩石边坡修复植物选择上应引起重视。     

植被叶片温度冠层温度预测与分析

为研究植被冠层降温效应并预测植被叶片温度和冠层温度,建立了一种绿色植被热平衡模型;根据土壤、冠层和大气的能量平衡,对模型进行理论求解和回归分析,给出了植被冠层叶片温度和冠层温度的显性函数表达式并对其影响因素进行分析。选取8种校园常见植被进行试验,并将试验结果与模型预测结果进行对比分析。结果表明:经验模型所预测植被叶片温度、冠层温度与试验测试结果较吻合;存在环境空气临界温度Tc,当TaTc时,植被叶片具有降温作用;Tc主要受植被叶片形态、环境空气相对湿度以及太阳辐射影响。     

干旱胁迫对中国石蒜叶片形态和部分生理指标的影响

通过盆栽试验,研究了干旱胁迫下中国石蒜(Lycoris chinensis)叶片的形态特征和部分生理指标的的变化。结果表明:随着干旱胁迫的加剧,叶片生长速度减慢;表皮细胞变小;气孔长宽比变大;气孔密度和气孔指数降低;相对含水量呈下降趋势;膜透性、POD和CAT活性均表现为先上升后下降趋势。除CAT活性外,上述指标在干旱胁迫下均有显著性差异(P0.05)。综合分析表明中国石蒜叶片对干旱胁迫具有一定的耐受性。     

甘蓝霜霉病内生拮抗细菌的筛选鉴定及防效研究

以感染霜霉病和健康的甘蓝叶片为试材,研究筛选了对甘蓝霜霉病菌有拮抗作用的内生细菌。结果表明:从健康的甘蓝幼苗中分离到18株内生细菌;用离体叶法进行测定,发现其中2株内生细菌对甘蓝霜霉病菌有拮抗作用,对其中一拮抗效果较好的菌株AC8进行田间防治试验,其防效达61.4%;通过形态观察、培养特征和生理生化特性鉴定,菌株AC8属于蜡状芽孢杆菌。     

水分胁迫处理对水榆花楸生理特性的影响

以2年生水榆花楸盆栽苗为材料,采用称重控水法,设置土壤含水量分别为25%～30%(重度干旱)、45%～50%(中度干旱)、60%～65%(轻度干旱)、75%～80%(对照)、90%～95%(水淹)5个处理,研究水分胁迫对水榆花楸幼苗生长和生理生化指标的影响。结果表明:(1)随胁迫加剧,水榆花楸苗高、地茎、叶面积及叶面积相对增长率逐渐减小。(2)随胁迫时间的延长,幼苗叶片超氧化物歧化酶活性在轻度干旱胁迫下增长缓慢,在中度干旱胁迫下逐渐升高而在重度干旱胁迫和水淹条件下呈现先增加后降低的趋势。(3)整个胁迫过程中,各处理叶片中的MDA含量呈现上升趋势,且同一时间段内MDA含量和相对电导率随胁迫程度加剧而升高;各处理叶片可溶性蛋白含量先降低后升高。可见水榆花楸幼苗能通过增强保护酶活性及提高可溶性蛋白含量等来缓解水分胁迫的伤害,表现出较强的抗性。     

不同栽培基质中碧玉兰受两种胁迫下对叶片细胞膜透性的影响

研究不同配比的栽培基质对碧玉兰的抗逆生理指标的影响;采用盆栽的方法进行干旱处理,研究干旱胁迫对不同栽培基质配方的碧玉兰叶片质膜透性的影响;通过浇灌不同浓度NaCl溶液,研究盐胁迫对细胞膜透性的影响。结果表明,不同栽培基质的碧玉兰受到干旱胁迫时,其相对电导率存在显著差异,在干旱胁迫下,配方1抗旱性较强,配方7是抗旱性较弱;在盐胁迫下,配方8抗盐性较强,配方1抗盐性较弱。本试验可为碧玉兰产业开发和其他兰花生长筛选出最适宜栽培基质提供技术参考。     

樱桃番茄气孔特征和气体交换参数对干旱胁迫的响应

以樱桃番茄为试材,采用基质培养的方法,使用不同浓度PEG 6000(0、5%、10%、15%)模拟干旱胁迫,研究了樱桃番茄叶片气孔特征、气体交换过程和叶绿素素含量对干旱胁迫的响应,以期为提升樱桃番茄在干旱地区土壤种植效率以及耐干旱品种的选育提供参考依据。结果表明:不同干旱处理对气孔长度、气孔周长、气孔面积、气孔宽度和气孔形状指数均产生显著的影响(P<0.05),除了气孔宽度外,均随着干旱胁迫的加剧而减少。随着干旱胁迫的加剧净光合反应速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)均呈现明显下降趋势(P<0.05)。但是,樱桃番茄叶片的细胞间CO_2浓度(Ci)随着干旱胁迫的加剧而升高,且与对照存在显著差异(P<0.05)。另外,干旱胁迫导致樱桃番茄叶片的水分利用效率(WUE)呈先减少后增加的趋势,但均小于对照。此外,樱桃番茄叶片的叶绿素含量随着干旱胁迫加剧呈现先上升后下降的趋势。表明干旱胁迫条件下樱桃番茄叶片主要通过调整单个气孔结构(气孔开度大小)及气孔分布特征(气孔密度和空间分布格局)及叶绿素含量来进一步优化气体交换效率。该研究结果不仅有助于深入理解干旱胁迫对樱桃番茄气孔特征、气体交换过程和叶绿素含量之间关系的影响机理,而且还将为提升樱桃番茄在干旱地区土壤种植效率以及耐干旱品种的选育提供参考依据。     

喜马拉雅紫茉莉对干旱的生理生态响应

以喜马拉雅紫茉莉1年生成年苗为试材,采用盆栽试验和自然干燥的方法,研究了喜马拉雅紫茉莉对土壤干旱胁迫的生理生态响应过程。结果表明:随着干旱程度的加剧,喜马拉雅紫茉莉叶片相对含水量(LRWC)及叶绿素(Chl)含量在中轻度干旱胁迫下变化幅度不大,在土壤含水量为8.88%~9.58%(28d)时,开始发生显著变化;脯氨酸和可溶性糖的含量随土壤相对含水量降低而增加;喜马拉雅紫茉莉通过SOD和POD的协同作用以清除体内氧自由基,达到适应和抵御干旱逆境的目的,并且POD活性作用大于SOD活性作用。喜马拉雅紫茉莉可通过渗透调节、抗氧化酶活性升高等途径增强对干旱环境的耐受性和适应性;喜马拉雅紫茉莉有较强的抗旱性,干旱胁迫28d(土壤含水量10%左右)为耐受极限。     

酿酒葡萄叶片光合特性对干旱胁迫的响应

以1年生葡萄幼苗“霞多丽”为材料,在幼苗期对其进行4个水平(5%、10%、15%、20%)的PEG-6000人工模拟干旱胁迫,利用Li-6400便携式光合作用系统测定干旱胁迫下的光合生理指标,研究干旱胁迫下酿酒葡萄幼苗叶片光合参数的变化。结果表明,干旱胁迫会显著影响酿酒葡萄幼苗的水分变化及光合特性。不同胁迫水平下,葡萄幼苗叶片的相对含水量(RWC)随干旱胁迫时间的延长而降低;叶绿素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和RuBP羧化酶活性均随着干旱胁迫时间的延长呈先升高后降低趋势,且在同一胁迫时间段内,随着PEG浓度增大,均表现出递减变化趋势;5%、10%PEG处理下,从胁迫开始至结束,葡萄幼苗叶片的叶绿素含量、Pn、Gs、Tr、Ci、RuBP羧化酶活性均高于对照,表明上述处理对光合作用具有一定的促进作用;15%、20%PEG处理下,前期(0～24 h)葡萄幼苗叶片的叶绿素含量、Pn、Gs、Tr、Ci(胞间CO₂浓度)、RuBP羧化酶活性均高于对照,但中后期(24～96 h)均远低于对照,表明上述处理对光合作用有一定的抑制作用。本研究结果在一...     

光强和水分胁迫对姜叶片光合特性的影响

 为探讨根际供水状况与姜叶片需光特性的关系,通过模拟干旱与遮光（50%）交互处理,研 究了自然光照正常供水（T1）、遮光正常供水（T2）、自然光照干旱（T3）、遮光干旱（T4）等对姜叶片光 合参数及叶绿素荧光参数的影响。结果表明,试验处理过程中,T1、T2 姜叶片Pn 无显著变化,而T3、 T4 均持续降低,且降幅以T3 较大;随处理时间的延长,T1、T2 的Ci 及Ls 未发生显著变化,而T3、T4 分别在胁迫1 d、3 d 后,其Ci 即升高而Ls 降低,表明胁迫初期T3、T4 姜叶片Pn 的降低主要为气孔限制, 而后期则以非气孔限制为主;处理6 d 时,尽管各处理姜叶片Pn 在午间均显著降低,但降幅以T3、T4 较 大,尤其T3 在午后未出现第二峰值,而T1、T2、T4 均表现为双峰曲线变化。试验处理过程中,T1、T3、 T4 姜叶片Fv/Fm 持续降低,NPQ 升高,但变幅以T3 较大,T4 次之,T1 较小,T2 则无显著变化;处理6 d 时,虽然各处理姜叶片Fv/Fm、ФPSⅡ、qP 均在午间显著降低,NPQ 显著升高,但变幅以T3 较大,T4、 T1 次之,T2 较小。表明干旱胁迫对姜叶片光化学效率的影响大于自然光照胁迫,而遮光则可缓解干旱胁 迫。     

高温干旱胁迫对牡丹叶PSⅡ功能及光能分配的影响

以耐旱的“胡红”和对干旱敏感的“洛阳红”2个不同抗性的牡丹品种为试材,研究了高温干旱协同胁迫下的牡丹叶片PSII功能及光能分配特性,以期为提高干旱胁迫下的牡丹抗性提供理论依据和实践支持。结果表明:高温干旱胁迫引起了2种牡丹叶片PSⅡ初始荧光(F0)、光下叶片初始荧光(F0′)、非光化学猝灭系数(qN)、天线热耗散百分率(Hd)、反应中心非光化学耗散百分率(Ex)的增加和最大荧光(Fm)、可变荧光(Fv)、暗适应最大光化学效率(Fv/Fm)、PSⅡ实际光能转换效率(Fv′/Fm′)、叶绿素荧光光化学猝灭系数(qP)、表观光合电子传递速率(ETR)的降低。胁迫前4d2个牡丹品种具有一定的光合保护机制,PSⅡ叶绿素荧光能量分配与对照无显著差异,PSⅡ功能没受到影响。但6d后光合保护机制受损严重,叶绿素荧光能量分配变化显著,Hd逐渐增加第12天时“胡红”和“洛阳红”分别比对照增加118.9%、153.0%。Pc和ETR逐渐降低,第12天时“胡红”Pc、ETR和“洛阳红”Pc、ETR分别比对照降低70.7%、73.8%和84.9%、97.2%。说明进入PSⅡ反应中心的能量减少,通过天线热耗散的能量增多,PSⅡ功能受抑。胁迫中后期2个牡丹品种间叶绿素荧光能量分配差异显著,抗性较差的“洛阳红”Hd和Ex百分率高于抗性较强的“胡红”,Ex增加造成光合机构更严重的可逆失活及破坏。表明抗性较强的“胡红”比抗性较弱的“洛阳红”,遭受高温干旱胁迫时光抑制程度更低,仍能维持相对较高的PSⅡ实际光能转换效率。     

高温和干旱胁迫对尾巨桉幼苗生理特性的影响

以木本植物尾巨桉无性系幼苗为试验材料,研究高温(40℃)和干旱胁迫(停止浇水)对其生理特性的影响。结果表明：随着高温和干旱胁迫处理时间的延长,幼苗受害指数、膜透性、丙二醛含量和脯氨酸含量均有不同程度的增高;叶片含水量、叶绿素含量均明显降低,干旱胁迫的影响大于高温胁迫的影响。     

Determining morphological and physiological parameters for the selection of drought-tolerant geraniums (Pelargonium x hortorum L. H. Bailey)

Summary

Greenhouse experiments were carried out to study the effect of drought stress on morphological and physiological parameters of Pelargonium hortorum, to define the most sensitive indicators that could be used to evaluate genotypes for tolerance to water stress. Nine genotypes of P. hortorum and two genotypes of the parental species (P. inquinans L. and P. zonale L.) were examined. Drought stress was induced by withholding water until the soil water potential reached –80 kPa, followed by recovery and applying another drought stress cycle. Growth decreased with drought stress with regard to all parameters and all genotypes, compared to well-watered plants. Production and loss of leaves were sensitive indicators of drought stress to discriminate between genotypes. A classification of genotypes was obtained from these parameters. Changes in leaf area, the density of stomata (mm^–2 or per leaf), leaf water content and leaf cell osmolarity during the drought cycle and after recovery were also studied. Changes in stomata mm^–2, leaf surface and cell osmolarity were found to be sensitive indicators of drought stress. Correlations between different parameters made it possible to obtain a robust classification of genotypes using only a few parameters. Significant variation was found between genotypes of P. hortorum in their response to drought stress.The different mechanisms which can be used by tolerant genotypes to adapt to drought stress are discussed. The present study provides a simple method to evaluate and select for water stress-tolerance in P. hortorum genotypes.     

基于熵权的TOPSIS模型在黄瓜适宜抗蒸腾产品评价中的应用

为了筛选适宜的抗蒸腾产品,提高黄瓜抗旱性,选用2种代谢型、2种成膜型和1种生长调节剂型共5种抗蒸腾产品进行叶面喷施处理,以喷施清水作为对照,测定黄瓜植株生长、植株生物量和产量品质指标,将熵权法和TOPSIS法相结合,对11个评价指标及6个评价方案进行综合分析.结果表明,代谢型国光抗蒸腾剂处理后黄瓜株高比CK提高1.64...     

Modelling development of broccoli (Brassica oleracea L. var. italica) from transplanting to head initiation

Summary

A model is suggested to predict head initiation in broccoli. Head initiation is defined as the time when the apex diameter reaches 0.6 mm and predictions are made from observations of air temperature. The model is constructed from three years of field experiments with three cultivars and four plantings per year. No juvenile phase after transplanting could be estimated and the model consists only of a head induction phase starting at transplanting. The rate of head induction is modelled by a piecewise linear temperature response function with a base, optimum, and maximum temperature. At optimum temperature the duration of the head induction phase is shortest. The estimates for base, optimum, and maximum temperature are 9.98C, 16.18C and 22.38C, respectively. The estimates for cultivar dependent thermal time requirements are 49 day-degrees, 55 day-degrees, and 38 day-degrees for cvs Caravel, Shogun and Emperor, respectively. The three cultivars were anticipated to have the same cardinal temperatures for head induction. The model of the head induction phases can account for 68% of the variation in the observed durations from transplanting to head initiation. A model of leaf appearance is used to standardize transplant size to four visible leaves at planting. The leaf appearance rate is described by a linear relationship to number of leaves and air temperature and the model can account for 89% of the variation in time from transplanting to appearance of a certain number of leaves. The temperature response of leaf appearance rate had a base temperature of about 2 to 38C, depending on cultivar, and showed no indications of having a temperature optimum below 208C. The leaf appearance rate at 158C range from 0.2 leaves per day for plants with four visible leaves to 0.4 leaves per day for plants with 14 visible leaves.     

Variation in baobab seedling morphology and its implications for selecting superior planting material

With the aim of helping to select superior planting material for drought characteristics, baobab seedlings from two countries, one in western and one in south-eastern Africa, were grown in a greenhouse and their growth and morphology were studied. Seedlings were grown for 18 weeks and several morphological characteristics (length, diameter and dry weights of different plant parts, number of leaves, stomatal density, among others) were recorded at different harvesting times. Biomass allocation changed with time: seedlings invested more in fine roots and leaves in the beginning of their growth while later they invested more in the development of the taproot. In general, at any harvest time, seedlings from Malawi were larger; but seedlings from Mali had higher relative growth rates and a faster ontogeny. Seedlings from Mali had shorter hypocotyls, their stems were thicker, they had fewer leaves, lower leaf area ratios and, in general, they had a higher stomatal density than those from Malawi. Significant differences between provenances within one country could also be observed. In general, seedlings from drier provenances were smaller overall, they had fewer leaves, higher taproot water content and stomatal density, characteristics often related to drought adaptation. Seedlings from drier provenances also invested more in their taproot, a key organ for baobab seedling survival. Although our seedlings were only grown under optimal conditions in a greenhouse, results from this study indicate that there is a great variation in baobab seedling growth, biomass allocation to plant parts and morphology, which gives opportunities to select high quality planting material.     

逆境胁迫对‘宁玉’草莓叶片自噬小体数量及其相关基因表达的影响

为探索自噬在草莓叶片响应逆境胁迫中的作用,以‘宁玉’草莓为试材,研究了在黑暗、高盐、涝害、高温和干旱胁迫处理下,叶片自噬活动的情况以及Fa ATG5、Fa ATG6、Fa ATG7、Fa ATG8C、Fa ATG8F、Fa ATG12这6个自噬相关基因在草莓叶片中的半定量和定量表达情况。结果显示:在5种胁迫条件下,草莓叶片自噬小体的数量发生变化,都达到4个以上,其中在盐胁迫3 d时达到最多,为35个,在高温胁迫和干旱胁迫下出现先上升后下降的现象,说明高温和干旱胁迫对草莓伤害最为严重。在5种胁迫条件下,自噬相关基因表达总体呈上升趋势,并且在高温胁迫条件下,Fa ATG5、Fa ATG7、Fa ATG8F、Fa ATG12表达水平先升高后下降。在干旱胁迫条件下,Fa ATG6、Fa ATG8C、Fa ATG8F表达水平先升高后下降。Fa ATG8C和Fa ATG8F这两个基因对草莓叶片中自噬小体的形成以及应答不同胁迫中的作用更为重要。     

闽西北桃小叶症病因诊断与区域性骤发诱因

2003—2005年闽西北桃产区大范围骤发"桃小叶症",典型症状为春梢展叶期叶片不能正常伸展,病叶狭小细长,呈丛生莲座状、花萎无果,各主栽品种均同时受害。经研究该病嫁接不传染,且经2年20个重复的发病果园病株叶片分析,含B≤9.71mg/kg,远低于适宜值下限20mg/kg,结合生殖障碍等形态症状与施B矫治疗效,诊断"桃小叶症"为重度缺B症。再则,根据萌芽期2月至翌年4月发病期各时段雨量与次年发病率的滑动相关分析还表明,中亚热带季风红壤缺B≤0.45mg/kg地区,桃生长季2月中旬—9月上旬的严重干旱是引发翌年桃小叶症区域性骤发的诱因,而非发病季当年春季的降水不足;同时由同类土壤的模拟干旱试验还表明,高温、干旱并不导致同类土壤热水溶性B明显下降,干旱对桃B吸收障碍另有原因。还就桃小叶症矫治提出相应措施。     

外源物质对干旱复水平邑甜茶抗氧化酶的影响

以苹果砧木平邑甜茶2a生实生苗为材料进行盆栽试验,研究比较了干旱复水条件下外源甜菜碱(GB)、脱落酸(ABA)和硝普纳(SNP,NO供体)对平邑甜茶幼苗抗氧化防护酶活性的影响。结果表明:外源GB、ABA和NO显著降低了干旱胁迫下平邑甜茶幼苗叶片质膜相对透性和MDA含量,重度胁迫时与CK相比,分别降低了13.5%、12.2%、18.4%与32.4%、14.4%、37.6%;外源GB、ABA和NO提高了叶片中SOD、CAT和POD的活性,在田间持水量30%时分别达到最大,与同期CK相比,POD活性分别增加13.5%、13.4%和24.4%,SOD活性分别增加15.3%、13.7%和16.2%,CAT活性则分别增加63.2%、53.7%和95.3%,之后酶活性开始下降。外源GB、ABA处理后GR、DHAR、APX和MDHAR的变化趋势与CAT等趋势相同,同样在田间持水量30%时酶活分别达到最大;NO处理后,GR、DHAR、APX的变化趋势亦相同,虽然NO对MDHAR活性比干旱处理有所升高,但差异不显著。复水后,不同外源物质下植物的抗旱生理指标变化趋势不尽相同。表明喷施外源GB、ABA和NO可有效的提高叶片的抗氧化系统酶的活性,增强平邑甜茶幼苗的抗旱能力。比较GB、ABA和NO处理,NO在提高平邑甜茶抗旱性方面效果最好,GB处理其次,ABA处理最低。     

新疆野扁桃抗旱性生理指标的测定

试验对浇水后的第10、15、20、25、30天的新疆野扁桃叶片进行抗旱性生理指标测定。结果表明,在浇水后20d,质膜相对透性达到最大,为2．9．465％;脯氨酸含量在浇水后20d达到最大值1230．275μg／g,与浇水后10d相比增长1倍;浇水后30d时,丙二醛含量明显上升,且含量达到最大值0．076μmol／g,与浇水后10d相比增加2倍。表明野扁桃具有一定的抗旱能力,但在缺水20～25d后,细胞组织会受严重伤害。