水稻花药对高温胁迫的生理响应

为了探明水稻花药在高温胁迫下的生理反应及适应机理,以耐热水稻品系996和热敏感水稻品系4628为材料,在人工气候室进行高温（9：00-17：00,37℃;17：00-9：00,30℃）和适温处理（9：00-17：00,30℃;17：00～9：00,25℃）,研究高温胁迫对水稻花药可溶性糖、可溶性蛋白质、热稳定蛋白、维生素C含量、膜透性及内源激素含量等生理特性的影响。结果表明,高温使水稻花药中可溶性糖含量、可溶性蛋白质含量和维生素C含量下降,热稳定蛋白含量上升;热敏感品系4628花药中丙二醛含量和相对电导率在高温胁迫下增幅大于耐热品系996;高温胁迫下,水稻花药中GA3和IAA含量降低,ABA含量上升,耐热品系996花药中GA3、IAA含量降低幅度小于热敏感品系4628,ABA含量增加幅度小于热敏感品系4628。     

热带地区不同水稻品种对土壤镉胁迫的生理生化响应

以热带地区主栽品种博优225和矮糯为材料,采用盆栽试验研究了不同水稻品种对土壤外源重金属Cd胁迫的耐性机理。结果表明:在各浓度镉胁迫下,2个品种水稻都是根累积的镉含量要高于茎叶和稻壳、糙米,即根>茎叶>稻壳>糙米;随着镉胁迫浓度的增加,细胞膜受损的伤害程度越大,矮糯质膜透性略高于博优225;随着Cd浓度的升高,水稻叶片丙二醛(MDA)、脯氨酸含量逐渐增加,且博优225的增加幅度明显大于矮糯,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性均呈上升趋势,且博优225明显高于矮糯;过氧化氢酶(CAT)活性呈下降趋势;表明同样条件下博优225受Cd毒害更严重。     

不同红小豆品种幼苗对干旱胁迫的生理响应

为筛选红小豆（Phaseolus angularis Linn.）幼苗抗旱性鉴定指标,采用盆栽控水方法,对红小豆3个品种‘保红947’、‘东北大红袍’、‘晋小豆5号’进行了苗期形态特征及根系生理生化特性的研究。结果表明：干旱胁迫抑制了红小豆3个品种植株的生长;重度干旱胁迫下,3个品种光系统Ⅱ（PSⅡ）的潜在活性（可变荧光/初始荧光,Fv/Fo）、最大光化学效率（可变荧光/最大荧光产量,Fv/Fm）、株高、叶面积、茎粗、根鲜重、根系活力、可溶性蛋白质含量等指标均随干旱胁迫强度的增加呈明显下降趋势,根冠比、根系脯氨酸（Pro）含量、可溶性糖含量、SOD活性、POD活性、MDA含量等指标随着干旱胁迫强度的增加呈明显上升趋势。综合各项生理指标,‘东北大红袍’在干旱胁迫下能保持相对较优的生理状态,抗旱性最强。通过主成分分析表明,株高、叶面积、茎粗、主根长、根鲜重、最大光化学效率、根系活力、可溶性糖含量、可溶性蛋白质含量、SOD活性、MDA含量等生理生化特性可作为鉴定红小豆苗期抗旱性的指标。     

罗布麻对不同浓度盐胁迫的生理响应

利用网室盆栽实验,研究不同浓度的NaCl（100-400mmol·L^-1）胁迫对罗布麻（Apocynum venetum）生长及生理特性的影响。结果表明,100mmol·L^-1NaCl处理显著降低了罗布麻植株的鲜重,但对其干重影响不大;随着盐浓度继续增加,罗布麻鲜重和干重显著下降。在盐胁迫下,罗布麻叶片内的丙二醛含量、电解质渗漏率、根部和地上部Na^＋的含量明显增加,K^＋的含量随着盐离子浓度的增加而降低。盐胁迫显著降低了地上部Ca^2＋的含量,而对根部Ca^2＋的含量没有影响。植株K^＋/Na^＋和Ca^2＋/Na^＋比值随着盐胁迫强度的增加而降低。盐胁迫显著促进了罗布麻根部对K^＋和Ca^2＋的选择性吸收及对K^＋的选择性运输。当NaCl浓度小于或等于200mmol·L^-1时,随着盐离子浓度的增加,罗布麻叶片内的脯氨酸和可溶性糖积累显著增加,而当NaCl浓度大于200mmol·L^-1时,这2种有机溶质含量显著下降。总体上,罗布麻通过积累无机离子、合成有机溶质及维持较高的K^＋、Ca^2＋选择性吸收和运输来适应一定浓度（≤200mmol·L^-1NaCl）的盐胁迫。     

不同福禄考品种对低温胁迫的生理响应及抗寒性综合评价

通过对14个福禄考品种在低温胁迫下相关生理指标进行分析,结果表明:可溶性糖含量随处理温度降低呈"升降升降"的变化趋势;可溶性蛋白含量随处理温度降低呈"降升降降"的变化趋势;不同品种脯氨酸、叶绿素、丙二醛含量和超氧化物歧化酶活性变化趋势不同,差异达到显著水平。运用主成分分析法和聚类分析法对14个福禄考品种进行抗寒性排序,将其分为3个抗寒等级:强抗寒品种为‘Sub-05’、‘Sub-Ja-03’和‘Sub-Ja-04’;中抗寒品种为‘Sub-Ja-01’、‘Sub-Ja-02’、‘Sub-06’、‘Sub-07’、‘Pan-02’和‘Pan-Ru-07’;弱抗寒品种为‘Pan-01’、‘Pan-Ru-06’、‘Pan-05’、‘Pan-04’和‘Pan-03’。丛生福禄考品种抗寒性优于锥花品种,与露地越冬观察的结果基本一致。     

罗布麻对不同浓度盐胁迫的生理响应

利用网室盆栽实验, 研究不同浓度的NaCl(100–400 mmol·L^–1)胁迫对罗布麻(Apocynum venetum)生长及生理特性的影响。结果表明, 100 mmol·L^–1NaCl处理显著降低了罗布麻植株的鲜重, 但对其干重影响不大; 随着盐浓度继续增加, 罗布麻鲜重和干重显著下降。在盐胁迫下, 罗布麻叶片内的丙二醛含量、电解质渗漏率、根部和地上部Na⁺的含量明显增加, K⁺的含量随着盐离子浓度的增加而降低。盐胁迫显著降低了地上部Ca²⁺的含量, 而对根部Ca²⁺的含量没有影响。植株K⁺/Na⁺和Ca²⁺/Na⁺比值随着盐胁迫强度的增加而降低。盐胁迫显著促进了罗布麻根部对K⁺和Ca²⁺的选择性吸收及对K⁺的选择性运输。当NaCl浓度小于或等于200 mmol·L^–1时, 随着盐离子浓度的增加, 罗布麻叶片内的脯氨酸和可溶性糖积累显著增加,而当NaCl浓度大于200 mmol·L^–1时, 这2种有机溶质含量显著下降。总体上, 罗布麻通过积累无机离子、合成有机溶质及维持较高的K⁺、Ca²⁺选择性吸收和运输来适应一定浓度(≤200 mmol·L^–1NaCl)的盐胁迫。     

2个欧李品种对碳酸盐胁迫生理响应的初步研究

在盆栽条件下,以不同浓度的NaHCO₃溶液浇灌农大欧李3和4号2年生组培苗,测定苗木叶片的生理指标。结果表明：随胁迫时间的延长,两个品种的叶绿素a呈先变化平缓后降低趋势,各处理间差异显著;叶绿素a/b在整个处理时期变化平稳;脯氨酸呈先变化平缓后升高趋势;农大欧李3号的电解质外渗率、MDA和POD活性呈先变化平缓后升高再降低的趋势,各处理间差异不显著;中、低浓度SOD活性整个胁迫期变化平缓,高浓度的在整个胁迫期间变化较大,各处理间差异极其显著;农大欧李4号电解质外渗率、SOD、POD和MDA在处理期间呈先升高后降低趋势,胁迫解除后,高浓度处理的电解质外渗率、SOD、POD活性上升、低浓度处理下降,MDA则相反。在长期的NaHCO₃胁迫过程中,农大欧李3号和4号都显示了强的耐盐性。     

黄连木对干旱胁迫的生理响应

研究了自然干旱条件下黄连木（Pistacia chinensis Bunge）的生理变化。结果表明,随土壤含水量的减少,叶绿素b含量、光合速率、叶片相对含水量与叶水势均下降;叶绿素a和可溶性糖含量、叶绿素a和b的比值及总叶绿素含量呈现上升的趋势;超氧化物歧化酶活性先升后降;丙二醛含量干旱胁迫前期升高,后期变化不明显;净光合速率、气孔导度和蒸腾速率随土壤含水量的减少逐步降低。气孔和可溶性糖含量都是影响黄连木光合速率的关键因子,干旱胁迫前12d光合速率主要受气孔限制,之后为非气孔限制。干旱胁迫前期渗透调节物质以可溶性糖为主,干旱胁迫较重时脯氨酸含量急剧升高,与可溶性糖同时起渗透调节作用。     

幼苗期不同水稻材料应答盐胁迫的生理差异分析

为了解耐盐水稻HD96-1幼苗期耐盐生理调控特性,该研究以籼型水稻HD96-1(耐盐性强)和93-11(耐盐性弱)为材料,采用营养液水培法,设置3种NaCl盐浓度(0、60、120 mmol·L^-1),对3叶期幼苗进行了7 d盐处理,测定和分析了两个材料的生长参数和生理生化指标。结果表明：(1)在盐胁迫下,水稻幼苗均表现为株高和假茎宽减小,根冠比增加;与93-11比,HD96-1株高和茎宽减小幅度低,根冠比增加幅度高;地上部和根系干重,HD96-1增加,而93-11减少。(2)盐胁迫后,水稻幼苗的丙二醛(MDA)、超氧阴离子(O₂^-)和过氧化氢(H₂O₂)含量均上升,但HD96-1增幅较93-11低。(3)在盐胁迫下,水稻幼苗体内的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性,以及抗坏血酸(AsA)、谷胱甘肽(GSH)、脯氨酸、可溶性糖和可溶性蛋白的含量均升高,HD96-1增幅高于93-11。综上表明,两个水稻材料幼苗...     

不同油橄榄品种对低温胁迫的生理响应及抗寒性综合评价

为了明确油橄榄的抗寒机理,对甘肃陇南地区主栽的6个油橄榄品种离体叶片进行低温胁迫(5℃、0℃、-5℃、-10℃)处理,并以18℃常温培养为对照,测定与抗寒性相关的生理生化指标,并采用隶属函数法对不同品种抗寒性进行综合评价。结果显示:(1)各油橄榄品种离体叶片相对电导率随处理温度的降低而呈\"S\"型曲线变化,结合Logistic方程得出不同品种油橄榄半致死温度介于-6.687℃~-3.706℃之间,且各品种的半致死温度顺序为‘皮肖利’<‘配多灵’<‘莱星’<‘阿斯’<‘鄂植8号’<‘佛奥’,其抗寒性大小依次为‘皮肖利’>‘配多灵’>‘莱星’>‘阿斯’>‘鄂植8号’>‘佛奥’。(2)随着胁迫温度降低,各油橄榄品种离体叶片叶绿素含量逐渐降低,可溶性糖含量基本呈逐渐增加趋势,而可溶性蛋白质含量、脯氨酸含量、丙二醛含量、SOD活性、POD活性和CAT活性则呈先升后降的趋势。(3)在-10℃低温胁迫下,油橄榄品种‘皮肖利’和‘配多灵’的叶片叶绿素含量比常温对照降幅较小,渗透调节物质含量和保护酶活性相对增幅较大,丙二醛含量增幅较小,而此时品种‘佛奥’和‘鄂植8号’各指标的变化趋势与之相反。(4)根据不同油橄榄品种的平均隶属度(抗寒性综合评价值)确定的品种抗寒能力大小顺序(‘皮肖利’>‘配多灵’>‘莱星’>‘阿斯’>‘鄂植8号’>‘佛奥’)与品种半致死温度的抗寒性表现顺序完全一致。研究表明,在低温胁迫条件下,‘皮肖利’和‘配多灵’等油橄榄品种能通过提高渗透调节物质含量和增强保护酶活性来缓解胁迫造成的过氧化伤害,从而表现出较强的抗寒能力;基于相对电导率的半致死温度和隶属函数法的综合评价均能准确鉴定油橄榄的抗寒性。     

大豆蚜危害胁迫对大豆叶片几个重要生理指标的影响

大豆蚜Aphis glycines Matsumura是为害大豆(Glycine max)的重要害虫,已给我国大豆生产造成了较为严重的经济损失。本研究通过测定大豆蚜危害胁迫后大豆叶片可溶性蛋白、非可溶性蛋白、可溶性糖含量及2种防御性酶——过氧化物酶(POD)、过氧化氢酶(CAT)活性的动态变化,探讨大豆蚜危害胁迫对大豆叶片几个重要生理指标的影响。研究结果表明,受到大豆蚜危害胁迫的大豆叶片与未受为害叶片中所含可溶性蛋白含量存在极显著差异(t0.01=11.814,df=4,P<0.01),且前者较后者含量明显增高1.73mg·g-1。与之相比较,非可溶性蛋白与可溶性糖含量分别在此两处理间无显著差异(t0.05=-1.104,df=4,P>0.05;t0.05=-2.639,df=4,P>0.05)。此外,受到大豆蚜危害胁迫的大豆叶片较未受为害叶片中所含POD活性有所升高,但在两处理间POD活性无显著差异(t=-2.639,df=4,P>0.05)。同时,受到大豆蚜危害的大豆叶片较未受为害的大豆叶片中CAT活性增强。本研究有助于揭示大豆蚜对大豆的危害机理,评价不同大豆品种对大豆蚜虫危害的耐受程度,也为大豆抗虫品种选育以及大豆蚜的可持续控制提供理论依据。     

Tree resistance to Lymantria dispar caterpillars: importance and limitations of foliar tannin composition

The ability of foliar tannins to increase plant resistance to herbivores is potentially determined by the composition of the tannins; hydrolyzable tannins are much more active as prooxidants in the guts of caterpillars than are condensed tannins. By manipulating the tannin compositions of two contrasting tree species, this work examined: (1) whether increased levels of hydrolyzable tannins increase the resistance of red oak (Quercus rubra L.), a tree with low resistance that produces mainly condensed tannins, and (2) whether increased levels of condensed tannins decrease the resistance of sugar maple (Acer saccharum Marsh.), a tree with relatively high resistance that produces high levels of hydrolyzable tannins. As expected, when Lymantria dispar L. caterpillars ingested oak leaves coated with hydrolyzable tannins, levels of hydrolyzable tannin oxidation increased in their midgut contents. However, increased tannin oxidation had no significant impact on oxidative stress in the surrounding midgut tissues. Although growth efficiencies were decreased by hydrolyzable tannins, growth rates remained unchanged, suggesting that additional hydrolyzable tannins are not sufficient to increase the resistance of oak. In larvae on condensed tannin-coated maple, no antioxidant effects were observed in the midgut, and levels of tannin oxidation remained high. Consequently, neither oxidative stress in midgut tissues nor larval performance were significantly affected by high levels of condensed tannins. Post hoc comparisons of physiological mechanisms related to tree resistance revealed that maple produced not only higher levels of oxidative stress in the midgut lumen and midgut tissues of L. dispar, but also decreased protein utilization efficiency compared with oak. Our results suggest that high levels of hydrolyzable tannins are important for producing oxidative stress, but increased tree resistance to caterpillars may require additional factors, such as those that produce nutritional stress.     

盐胁迫对大米草幼苗某些生理指标的影响

研究了大米草幼苗在不同培养盐度(0、20、30、50、100mmol/LNaCl)下,MDA、游离脯氨酸、可溶性糖、可溶性蛋白质含量以及保护酶(SOD、POD、CAT)活性等生理指标的变化情况。结果表明:保护酶(SOD、POD、CAT)活性在盐胁迫40d前逐渐上升且达显著差异。随着胁迫时间延长,MDA含量与CK相比逐渐降低。随着盐分胁迫浓度的增加及盐胁迫时间延长,大米草叶片中游离脯氨酸、可溶性糖、可溶性蛋白质含量呈上升趋势。在盐胁迫下,渗透调节物质的积累作用是大米草对盐胁迫的主要响应过程,其体内的抗氧化保护酶在此过程中也发挥了重要的作用。     

Lygus hesperus （Heteroptera： Miridae） tolerates high concentrations of dietary nickel

Nickel hyperaccumulator plants contain unusually elevated levels of Ni （〉 1 000 μg Ni/g）. Some insect herbivores, including Lygus hesperus （Western tarnished plant bug）, have been observed feeding on the California Ni hyperaccumulator Streptanthus polygaloides. This bug may be able to utilize S. polygaloides as a host either through its feeding behavior or by physiological tolerance of Ni. This experiment determined the Ni tolerance of L hesperus by offering insects artificial diet amended with 0, 0.4, 1, 2, 4.5, 10, 20 and 40 mmol Ni/L and recording survival. Survival varied due to Ni concentration, with diets containing 10 mmol Ni/L and greater resulting in significantly lower survival compared to the control （0 mmol Ni/L） treatment. Insects tolerated diet containing as much as 4.5 mmol Ni/L, a relatively elevated Ni concentration. I conclude that L hesperus can feed on S. polygaloides because it is Ni-tolerant, probably due to physiological mechanisms that provide it with resistance to plant chemical defenses including elemental defenses such as hyperaccumulated Ni.     

Specialist and generalist herbivores exert opposing selection on a chemical defense

* Plant defense traits often show high levels of genetic variation, despite clear impacts on plant fitness. This variation may be partly maintained by trade-offs in the defense against multiple herbivore species, for example between generalists and coevolved specialists. Despite a long-standing discussion in the literature on the subject, no study to date has specifically manipulated specialist and generalist herbivores independently of one another to determine whether the two guilds exert opposing selection pressures on specific defensive traits. * In two separate experiments, the dominant specialist and generalist herbivores of Brassica nigra were independently manipulated to test whether the composition of the herbivore community altered the direction of selection on a major defensive trait of the plant, sinigrin concentration. * It was found that generalist damage was negatively correlated but specialist loads were positively correlated with increasing sinigrin concentrations; and sinigrin concentration was favored when specialists were removed, disfavored (past an intermediate point) when generalists were removed and selectively neutral when plants faced both generalists and specialists.     

Timing of induced resistance in a clonal plant network

After local herbivory, plants can activate defense traits both at the damaged site and in undamaged plant parts such as in connected ramets of clonal plants. Since defense induction has costs, a mismatch in time and space between defense activation and herbivore feeding might result in negative consequences for plant fitness. A short time lag between attack and defense activation is important to ensure efficient protection of the plant. Additionally, the duration of induced defense production once the attack has stopped is also relevant in assessing the cost–benefit balance of inducible defenses, which will depend on the absence or presence of subsequent attacks. In this study we quantified the timing of induced responses in ramet networks of the stoloniferous herb Trifolium repens after local damage by Mamestra brassicae larvae. We studied the activation time of systemic defense induction in undamaged ramets and the decay time of the response after local attack. Undamaged ramets became defense‐induced 38–51 h after the initial attack. Defense induction was measured as a reduction in leaf palatability. Defense induction lasted at least 28 days, and there was strong genotypic variation in the duration of this response. Ramets formed after the initial attack were also defense‐induced, implying that induced defense can extend to new ramet generations, thereby contributing to protection of plant tissue that is both very vulnerable to herbivores and most valuable in terms of future plant growth and fitness.