Effect of Azotobacter vinelandii and compatible solutes on germination wheat seeds and root concentrations of sodium and potassium under salt stress

The effect of plant growth-promoting Rhizobacteria (PGPR) and exogenous application of compatible solutes on seed germination and root concentrations of sodium and potassium of two wheat varieties (Triticum durum L.) were evaluated under saline stress. In this experiment, Azotobacter vinelandii strain DSM85, glycine betaine and proline were used. Inoculated seeds for each variety were placed on Whatman paper in 9 cm Petri dishes containing 15 mL of distilled water or NaCl solutions at various concentrations (control, 100, 200, 300 mM) supplemented with or without glycine betaine (GB) or proline at 5 mM. The results indicated that addition of proline (5 mM) stimulated the production of indol acetic acid and the growth of A. vinelandii at 200 and 300 mM NaCl, respectively. The germination rate index and the germination final percentage decreased significantly (p < 0.05) with increasing salinity level. The germination was significantly diminished at 300 mM with significant variation among varieties and Waha variety had higher germination percentage than Bousselam variety. Inoculation of seeds by A. vinelandii and exogenous application of proline had significantly positive effect on the germination at this concentration of NaCl. The rate of accumulation of Na+ in roots was important at 100 mM and increased at 200 mM. The concentration of K+ decreased when salinity increased. The effect of inoculation or inoculation with proline decreased the accumulation of Na' and reduced the loss of K+ under salt stress. From the present study we can conclude that the use of A. vinelandii strain DSM85 and external application of low concentrations of proline on seeds might be considered as a strategy for the protection of plants under saline stress.     

土培条件下不同盐分梯度对水稻产量及其生理特性的影响

以南粳9108和甬优2640为材料,设置6个土壤含盐量(0%、0.07%、0.14%、0.21%、0.28%、0.35%),研究不同盐分梯度对水稻产量和生理特性的影响。结果表明:(1)盐胁迫影响水稻的生长和发育进程。株高、叶面积、干物质量等形态指标均随盐浓度的上升而下降;稻谷产量亦随盐浓度增加而下降,在0.14%、0.21%、0.28%、0.35%盐浓度处理时产量显著下降,南粳9108分别减产14.14%、43.65%、58.91%、65.68%,甬优2640分别减产20.25%、31.97%、40.41%、49.82%。(2)随着盐浓度的增加,2个参试品种抽穗期叶片抗氧化酶活性均呈先升后降趋势,在0.07%处理下达最高值。(3)抽穗期叶片中游离脯氨酸含量随盐浓度的上升而增加,盐浓度大于0.14%,游离脯氨酸含量较对照显著增加。(4)盐胁迫下,水稻植株吸收Na~+并置换出K~+,除叶片中K~+变化无规律之外,随着盐浓度上升,各部位K~+含量均下降,Na~+含量均上升,K~+/Na~+均呈下降趋势。茎鞘与叶运输的SK、Na随盐浓度的上升而上升,茎选择性运输K~+而抑制Na~+进入叶片;根与茎的SK、Na随盐浓度的上升而下降,茎吸收Na~+并输出K~+到根系。总体而言,低盐浓度对高产水稻品种产量和生理特性无显著影响,盐浓度大于0.07%时影响显著。     

海水浇灌对不同品种火龙果扦插苗生长和若干生理指标的影响

为明确海水胁迫对火龙果生长生理的影响,以不同品种火龙果(‘帝龙’、‘红龙’、‘紫蜜龙’和‘白龙’)为研究对象,研究了海水(浓度为0、10%、20%和30%)浇灌下不同品种火龙果生长指标和生理特征的变化。结果表明:(1)海水浇灌下4个品种火龙果地上部鲜重均表现为减小趋势,但10%海水浇灌可显著增加‘帝龙’的株高增加量。(2)与淡水相比,海水浇灌下4个品种火龙果地上部和根部K+/Na+均呈不同程度下降趋势,当海水浓度为30%时,与其他3个品种相比,‘帝龙’地上部和根部K+/Na+下降幅度最小。(3)4个品种火龙果地上部可溶性糖含量、脯氨酸含量、CAT活性和SOD活性随海水浓度增加均呈先上升后下降趋势。其中,20%海水处理下,‘帝龙’可溶性糖含量、脯氨酸含量和CAT活性上升幅度均高于其他品种。可见,低浓度海水胁迫下,火龙果表现出一定耐盐性,且‘帝龙’耐盐性相对较好。     

Antioxidant Defense Mechanisms of Salinity Tolerance in Rice Genotypes

In order to elucidate the role of antioxidant responses in salinity tolerance in rice genotypes under salt stress, experiments were conducted using four rice varieties, including salt-sensitive BRRI dhan 28 and three salt-tolerant varieties BRRI dhan 47, BINA dhan 8 and BINA dhan 10. Thirty-day-old rice seedlings were transplanted into pots. At the active tillering stage(35 d after transplanting), plants were exposed to different salinity levels(0, 20, 40 and 60 mmol/L NaCl). Salt stress caused a significant reduction in growth for all the rice genotypes. Growth reduction was higher in the salt-sensitive genotype than in the salt-tolerant ones, and BINA dhan 10 showed higher salt tolerance in all measured physiological parameters. The reduction in shoot and root biomass was found to be minimal in BINA dhan 10. Chlorophyll content significantly decreased under salt stress except for BINA dhan 10. Proline content significantly increased in salt-tolerant rice genotypes with increased salt concentration, and the highest proline content was obtained from BINA dhan 10 under salt stress. Catalase and ascorbate peroxidase activities significantly decreased in salt-sensitive genotype whereas significantly increased in salt-tolerant ones with increasing salt concentration. However, salt stress significantly decreased guaiacol peroxidase activity in all the rice genotypes irrespective of salt tolerance. K~+/Na~+ ratio also significantly decreased in shoots and roots of all the rice genotypes. The salt-tolerant genotype BINA dhan 10 maintained higher levels of chlorophyll and proline contents as well as catalase and ascorbate peroxidase activities under salt stress, thus, this might be the underlying mechanism for salt tolerance.     

海水灌溉对椰子幼苗叶片若干生理特性的影响

以海南本地高种与文椰2号矮种2个有代表性的椰子品种幼苗为试材，在温室大棚条件下，采用盆栽土培法，研究不同浓度海水对2种椰子幼苗叶片相对含水量、丙二醛、可溶性糖、脯氨酸、K+、Na+含量及K+/Na+值等生理特性的影响。结果表明：低浓度海水灌溉(30%)，2种椰子幼苗长势良好，叶片相对含水量、可溶性糖、脯氨酸、K+、Na+含量及K+/Na+值等生理特性与对照相比无明显差异。随着海水浓度的升高，2种椰子幼苗各项指标与对照组的差异逐渐明显。高浓度海水灌溉(90%)时，海南本地高种与文椰2号叶片相对含水量及K+/Na+值均显著降低，脯氨酸、可溶性糖、Na+含量显著升高；海南本地高种较文椰2号Na+含量变化幅度大，K+/Na+值下降更剧烈，而文椰2号矮种叶片相对含水量下降趋势更为明显、可溶性糖含量变化幅度更大，脯氨酸变化趋势相近。2种椰子幼苗中丙二醛含量变化均较为复杂，呈现先升高后降低再升高的趋势。     

盐胁迫对垂盆草生长和生理特性的影响

以垂盆草为材料,研究不同浓度NaCl[0(对照)、25、50、100、150、200 mmol/L]对垂盆草生长和生理特性的影响.结果表明:与对照相比,随着NaC1浓度的增加,垂盆草鲜重、干重、含水量、K+含量、根Na+/叶Na+、叶的K+/Na+和SOD活性均呈下降趋势;而Na+、游离氨基酸、可溶性糖、有机酸、脯氨酸、丙二醛含量和质膜透性均呈上升趋势;叶绿素含量、硝酸还原酶活性呈先上升后下降趋势,而NO3-含量则呈相反的变化趋势.综合分析显示,盐胁迫对垂盆草生长有抑制作用,其耐盐阈值为100 mmol/L NaCl;盐胁迫下垂盆草通过积累Na+、有机酸、游离氨基酸、可溶性糖、脯氨酸进行渗透调节.     

Effect of defoliation and drought stress on yield components and chlorophyll content of wheat

In order to examine the effects of source restriction and drought stress on yield components, flag leaf chlorophyll content and Relative Water Content (RWC) of wheat cultivars, a greenhouse experiment was carried out at Shiraz University, Shiraz, Iran, during 2009-2010. The wheat cultivars including Shiraz, Bahar, Pishtaz, Sistan and Yavaros were sown in 5 kg plastic pots. The source manipulation treatments including control (C), defoliation of all leaves (D1), defoliation of all leaves except the flag leaf (D2) and defoliation of all leaves except the flag leaf and penultimate leaf (D3), were imposed at anthesis. Results showed that source restriction decreased number of grain per spike significantly in Shiraz cultivar under drought stress condition. Maximum 100-grain weight was observed in C treatment of Yavaros and Shiraz under well-watered condition. Among the defoliation treatments under drought stress condition, D2 in Pishtaz and D1 in Shiraz had the highest (3.66 g) and lowest (2.71 g) 100 grain weight, respectively. In all cultivars drought stress decreased main shoot yield significantly but in Pishtaz and Sistan decreasing rate was less than the other cultivars. RWC in Shiraz decreased sharply from 92.1% in well-watered to 66.7% (27.5% reduction) under drought stress at 10 DAA. After anthesis, Pishtaz and Sistan maintained higher content of flag leaf chlorophyll (from 49.4 to 56.8 SPAD unit) under drought stress condition. Generally, selection and culture of cultivars that had small responses to defoliation might be a useful strategy in yield improvement of wheat in areas where the water availability is low.     

盐胁迫条件下杂交水稻种子发芽特性和幼苗耐盐生理基础

 两个杂交稻组合汕优10号和两优培九种子分别放在H2O、50 mmol/L、100 mmol/L和150 mmol/L的NaCl溶液中于30℃下发芽，测定种子发芽性能和淀粉酶活性及幼苗保护酶活性、丙二醛（MDA）含量和脯氨酸、可溶性糖、果糖和蔗糖等相容性溶质含量。结果表明，盐胁迫条件下杂交水稻种子平均发芽时间延长，发芽指数降低，但发芽势和发芽率变化不明显。盐胁迫后明显降低两优培九种子α，β-淀粉酶活性，而汕优10号中， 除在50 mmol/L NaCl溶液中α-淀粉酶活性高于对照（H2O）外，其余处理均降低了α，β-淀粉酶活性。不同盐胁迫程度下杂交水稻幼苗超氧物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶(CAT)活性和丙二醛含量及脯氨酸、可溶性糖、果糖和蔗糖等相容性溶质含量变化有差异，但未见规律性趋势。杂交水稻幼苗相对含水量和耐盐比率随着盐胁迫程度加深而明显下降。试验还表明，盐胁迫条件下杂交水稻组合汕优10号种子发芽性能比两优培九好，淀粉酶和保护酶活性、相容性溶质含量和相对含水量及耐盐指数和耐盐比率也均高于两优培九，说明汕优10号幼苗耐盐性强于两优培九。     

不同小麦品种苗期抗氧化特性及根系活力对盐胁迫的响应

为探讨不同耐盐性小麦品种苗期的生理差异,以小麦品种济麦22、青麦6号、德抗961、青丰1号为材料,在Hoagland营养液培养条件下,分析了NaCl胁迫对小麦幼苗叶片抗氧化酶活性、渗透调节物质含量及根系活力的影响。结果表明,随盐浓度及胁迫时间的增加,叶片SOD活性、可溶性蛋白含量不同程度地减小;POD活性及根系活力呈先增后减趋势,且均在胁迫1 d时出现最大值;MDA含量、游离脯氨酸含量不同程度地升高。品种间6个指标因盐胁迫浓度及胁迫天数的不同表现出不同的差异性,其中根系活力对于品种耐盐性有较强的鉴定价值;耐盐性高的青麦6号、德抗961各指标均显著高于耐盐性弱的济麦22和青丰1号。     

外源脯氨酸对镍胁迫下小麦幼苗生长的影响

为探究外源脯氨酸对镍胁迫下小麦根系生长发育的影响,以小麦品种轮选988为材料,采用溶液培养法,研究了不同浓度的脯氨酸对10μmol·L~(-1) Ni~(2+)胁迫下小麦幼苗株高和根系生长的影响。结果发现,镍胁迫严重抑制小麦生长;而外施脯氨酸对小麦幼苗的株高和根系生长的各项指标均有正向效应,以外施5mmol·L~(-1)脯氨酸的效果最好。与单独Ni~(2+)胁迫相比,外施5mmol·L~(-1)脯氨酸后,小麦幼苗根长、株高、根鲜重和根干重分别上升了24.8%、12.5%、16.0%和20.0%;超氧化物歧化酶(SOD)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)活性分别升高了54.30%、43.00%、13.08%、67.67%;超氧阴离子(O_2~-·)自由基、过氧化氢(H_2O_2)、丙二醛(MDA)含量分别下降了56.65%、34.54%、32.35%;渗透调节物质游离脯氨酸(Pro)和可溶性糖的含量均显著下降;根系活力上升了233.83%。外源脯氨酸可以显著提高小麦根的抗氧化能力,进而增强小麦的抗逆性,缓解镍对小麦根系的毒害作用。     

Salinity induced changes in photosynthetic pigment and antioxidant responses in Sesuvium portulacastrum

The production of leaf and root antioxidant changes when exposed to saline conditions were investigated in the perennial halophyte Sesuvium portulacastrum L. Plants were grown with a nonsterilized soil and sterilized soil with 50 and 100% of sterilized seawater on 25, 55 and 85 Days After Planting (DAP). The plants were harvested on 30th, 60th and 90th DAP and used for analyzing the photosynthetic pigments, antioxidant enzyme activities viz., Superoxide dismutase (SOD; EC1.15.1.1) Ascorbate peroxidase (APX, EC 1.11.1.11) and non enzymatic antioxidant contents like ascorbic acid, alpha-tocopherol, reduced glutathione were determined. Plants exposed to salinity, either alone (SSW) sterilized seawater/unsterilized soil (USS) along with higher pigments, antioxidative enzymes and Na+ ions response. This tendency was generally more marked in SSW/USS plants when compared to SSW/SS plants. The concentration of SSW/SS was negatively correlated with the antioxidative capacity of the plant, either enzymatic or non enzymatic and K+ ions. These data suggest that the enhancement of the antioxidative response is of crucial significance for S. portulacastrum plants growing under saline conditions.     

盐胁迫下 4 个不同耐盐基因型水稻 Na+ 、K+ 积累效应

选取耐盐性较强的水稻株系‘Fl478’、‘JX99’、‘Pokkali’和盐敏感型品种‘IR29’,设置 6 个 NaCl 浓度梯度处理, 分别为 0、0.1%、0.2%、0.3%、0.4%、0.5%,采用桶栽土培的方法培育至孕穗期,研究盐胁迫对孕穗期水稻植株不同 器官 Na+ 、K+ 分配规律与积累的影响。结果表明：（1）盐胁迫下水稻株系不同器官 Na+ ,K+ 的积累效应存在差异,水稻 株系耐盐性的差异主要表现在根系,而叶鞘对 Na+ 、K+ 的吸收与分配的差异明显。（2）耐盐植株根系聚 Na+ 能力较强, 叶片、叶鞘积累较多的 K+ ,而感盐品种根系积累 K+ 和 Na+ 以缓解根系渗透胁迫,调节根系 Na+ /K+ 平衡稳态,保持水稻 正常的代谢活动。（3）叶鞘是水稻植株关键的 Na+ -K+ 调库,通过吸收和分配 Na+ 来调节根、叶、叶鞘 Na+ /K+ 平衡以提 高水稻耐盐性。（4）耐盐株系叶鞘向叶片选择运输 K+ 的能力、限 Na+ 运输能力强于盐敏感品种,叶鞘对 Na+ 、K+ 吸收 与分配运输能力的大小,决定水稻株系的耐盐性,具体表现耐盐品种叶鞘向吸收与运输 K+ 能力较强、根系限 Na+ 能力 显著高于感盐植株。（5）0.4%~0.5%盐浓度限制水稻叶鞘 Na+ -K+ 库吸收与分配能力,各组织中 Na+ /K+ 失衡,植株耐盐 性降低,受盐害程度加深。（6）盐胁迫促进水稻株系叶鞘向根系吸收较多 Na+ 和向叶片、根系输出 K+ ,却限制 Na+ 对 叶片的分配,保证根系保持较高的 K+ /Na+ ,耐盐幼嫩叶片积累较多的 K+ 以维持叶片组织保卫细胞渗透平衡,保证水稻 植株获得生活必需的光合原料,而盐敏感植株积累的 K+ 主要用于缓解组织渗透胁迫,以维持正常生命活动。     

外源水杨酸对Hg~(2+)胁迫下小麦幼苗生长及生理的影响

为了解水杨酸(SA)对Hg2+胁迫小麦幼苗生长的缓解作用,以小麦品种豫麦58号为材料,采用室内水培法分析了在Hg2+胁迫下小麦幼苗经不同浓度SA处理后的生长及生理变化。结果表明,外施SA能显著提高Hg2+胁迫下小麦幼苗的根长、株高、单株鲜重,叶片叶绿素、脯氨酸和可溶性蛋白含量,以及抗氧化酶活性和根系活力(P0.05),极显著降低丙二醛含量与超氧阴离子产生速率(P0.01)。说明外施SA可通过提高小麦幼苗可溶性蛋白和脯氨酸含量及抗氧化酶活性来维持细胞膜的稳定性,降低膜脂过氧化伤害程度,从而缓解了Hg2+胁迫对幼苗生长的抑制作用,其中以40mg·L-1 SA缓解效果最好。     

重金属Pb2+、Cd2+胁迫对青稞幼苗抗氧化能力的影响

为了解重金属对青稞幼苗的伤害机理以及青稞对重金属胁迫的抗性作用,以青稞幼苗为实验材料,采用水培方法研究了50 mg·L^-1 Pb²⁺、Cd²⁺胁迫对青稞幼苗叶片相对含水量（RWC）、丙二醛（MDA）和脯氨酸含量、抗氧化酶活性的影响。结果表明,50 mg·L^-1 Pb²⁺ 胁迫下青稞幼苗的叶片相对含水量（RWC）变化不大,丙二醛（MDA）和脯氨酸含量、过氧化物酶（POD）和过氧化氢酶（CAT）活性在胁迫后期有所升高,超氧化物歧化酶（SOD）活性在前期升高比较明显,其后缓慢下降。50 mg·L^-1 Cd²⁺胁迫下青稞幼苗叶片RWC明显减少,MDA含量显著增加,脯氨酸含量先急剧升高后下降,POD、CAT活性随着胁迫时间的增加而显著增强,其中CAT活性在胁迫末期稍有下降,SOD活性先明显升高后下降。综合来看,青稞幼苗在受到相同浓度Pb²⁺、Cd²⁺胁迫时,对Pb²⁺的抵抗能力大于Cd²⁺。     

铬(Cr~(6+))胁迫对不同基因型小麦种子萌发及幼苗抗氧化和渗透调节的影响

为明确小麦种子萌发对Cr~(6+)胁迫响应的品种间差异及其Cr~(6+)耐性差异的生理机制,以耐Cr~(6+)品种扬麦16和Cr~(6+)敏感品种豫麦51为材料,研究了不同浓度的Cr~(6+)(0、10、50、100、150μmol·L~(-1))处理对种子萌发、α-淀粉酶活性、幼苗生长、活性氧水平、抗氧化酶活性和渗透调节物质含量的影响。结果表明,10mol·L~(-1) Cr~(6+)处理下,小麦种子的萌发过程未受到明显影响。随着Cr~(6+)处理浓度的进一步增加,小麦种子发芽势、发芽率、根长逐渐下降,扬麦16受抑制的程度较豫麦51轻;种子α-淀粉酶活性、根系可溶性蛋白和可溶性糖含量呈现先升后降的趋势;根系游离脯氨酸、丙二醛、O_2~和H_2O_2含量逐渐升高。相同浓度Cr~(6+)处理下,扬麦16的种子α-淀粉酶活性、根系可溶性糖和游离脯氨酸含量显著高于豫麦51,而根系丙二醛、O_2~和H_2O_2的含量显著低于豫麦51。在Cr~(6+)胁迫下,小麦根系SOD、POD、APX和GR的活性总体上呈现先升后降的趋势。在高浓度Cr~(6+)(150mol·L~(-1))处理下,扬麦16的种子α-淀粉酶、根系SOD、POD、APX和GR活性受抑制程度均明显小于豫麦51。     

镉胁迫对不同水稻基因型植株生长和抗氧化酶系统的影响

 以籽粒镉积累水平不同的两种品种（丙97252，低积累型；秀水63，高积累型）为材料，研究了镉胁迫对水稻植株生长和抗氧化酶系统的影响。采用水培试验，镉处理设0.0、0.1、1.0和5.0 μmol/L 4个水平。结果表明，镉胁迫抑制植株生长和叶绿素合成，改变植株丙二醛（MDA）含量和超氧物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）活性。在抗氧化酶活性上，根和地上部对镉胁迫的反应存在着差异。总体上，SOD、CAT和POD活性随镉水平的提高而减少，而MDA含量则表现相反。根和地上部MDA含量随着培养液中镉浓度提高而增加，且增加幅度秀水63明显大于丙97252。与对照相比，生长在5.0 μmol/L Cd处理下的植株， SOD活性在孕穗期下降46%~52%，在分蘖期仅下降13%~19%。高浓度镉胁迫下，两品种在MDA含量的增加幅度和叶绿素含量的降低幅度上表现不同，显示出它们对镉的耐性存在着差异。     

6-BA对Hg2+胁迫下小麦幼苗渗透调节物质及抗氧化特性的影响

为探讨6-苄氨基腺嘌呤(6-BA)对Hg2+胁迫下小麦幼苗生长的调节作用,采用营养液水培法,以小麦品种807为材料,分析了叶面喷施不同浓度的6-BA对Hg2+胁迫下小麦幼苗叶片中渗透调节物质含量、抗氧化酶活性及抗氧化物质含量的影响。结果表明,50mg·L-1 HgCl2处理后,小麦幼苗叶片的可溶性糖和可溶性蛋白含量显著降低,过氧化物酶(POD)和超氧化物歧化酶(SOD)活性下降,还原型抗坏血酸(AsA)和还原型谷胱甘肽(GSH)含量显著降低。叶面喷施一定浓度的6-BA能够提高Hg2+胁迫下小麦幼苗叶片的可溶性糖和可溶性蛋白含量,显著提高小麦幼苗叶片的POD、SOD活性和AsA、GSH含量,降低脱氢抗坏血酸(DHA)和氧化型谷胱甘肽(GSSG)含量,提高小麦幼苗叶片的AsA/DHA和GSH/GSSG比值,从而缓解Hg2+胁迫对小麦幼苗生长的抑制作用。叶面喷施10mg·L-1 6-BA对缓解小麦幼苗Hg2+胁迫效果最好。     

亚精胺对渗透胁迫下小麦幼苗渗透调节物质含量和脯氨酸代谢酶活性的影响

为了探讨多胺提高小麦抗旱性的机理,以两个抗旱性不同的小麦品种(豫麦48,抗旱性较弱;洛麦22,抗旱性较强)为材料,研究了亚精胺对短期渗透胁迫下小麦幼苗叶片渗透调节物质含量以及脯氨酸代谢的调控效应。结果表明,渗透胁迫下,两个小麦品种幼苗叶片中脯氨酸、葡萄糖和蔗糖含量增加,且抗旱性较强的洛麦22增加幅度显著大于抗旱性较弱的豫麦48;脯氨酸代谢关键酶Δ1-吡咯啉-5-羧酸合成酶(P5CS)和Δ1-吡咯啉-5-羧酸还原酶(P5CR)活性增强,且洛麦22的P5CS活性增强幅度大于P5CR。但渗透胁迫处理对两个品种鸟氨酸转氨酶(OAT)活性影响不大。外源亚精胺处理则进一步提高了渗透胁迫下脯氨酸、葡萄糖、蔗糖含量以及P5CS和P5CR活性,且对抗旱性较弱的豫麦48效应较明显,但对两个品种的OAT活性基本没什么影响。这些结果表明,外源亚精胺处理能通过提高脯氨酸合成代谢谷氨酸途径的关键酶P5CS和P5CR的活性促进脯氨酸和可溶性糖的积累,从而提高小麦幼苗的保水性,增强其抗旱性,对抗旱性较弱的小麦品种的效果更加明显。     

6-BA浸种对HgCl2胁迫下小麦种子萌发和幼苗生长的影响

为探讨6-苄基腺嘌呤（6-BA）浸种对HgCl₂胁迫下小麦种子萌发及其幼苗生长的缓解作用,以3个小麦品种为材料,研究了不同浓度6-BA浸种对200 mg·L^-1HgCl₂胁迫下小麦种子发芽、幼苗生长、抗氧化酶活性、可溶性蛋白和丙二醛含量的影响。结果表明,200 mg·L^-1HgCl₂处理后,3个小麦品种种子的发芽势、发芽率、根长、芽长和鲜重降低,幼苗的抗氧化酶活性和可溶性蛋白含量降低,丙二醛含量增加。一定浓度6-BA浸种可以缓解HgCl₂胁迫对小麦种子萌发的抑制作用,但对小麦的根长、芽长和鲜重的影响因小麦品种而不同。HgCl₂胁迫下,3个小麦品种幼苗的SOD、POD活性和可溶性蛋白含量随着6-BA浓度的增加均基本呈先升高后降低的趋势,最佳6-BA浓度因品种而不同;3个小麦品种的MDA含量均呈先降低后升高的趋势,以6-BA浓度为15 mg·L^-1时MDA含量最低。说明一定浓度6-BA浸种能够缓解HgCl₂胁迫对小麦种子萌发和幼苗生长的毒害作用,但最佳6-BA浓度因小麦品种的不同而不同。     

淹水对糯玉米耐涝性差异近等基因系生理指标的影响

以耐涝性不同的Zz-R和Zz-S为试材,采用盆栽淹水试验,研究淹水胁迫下玉米生理指标的差异。结果表明,淹水胁迫下,耐涝系Zz-R超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸酶(APX)活性与对照相比有所增加,且Zz-R增加幅度大于Zz-S。随着淹水时间的延长,Zz-R与对照相比仍表现为增加趋势;淹水胁迫8 d时,Zz-S与对照相比有所下降。淹水胁迫下,Zz-R和Zz-S的MDA含量均高于对照,且Zz-S增加幅度大于Zz-R;Zz-R和Zz-S的脯氨酸含量也显著高于对照,且Zz-R增加幅度大于Zz-S。近等基因系间耐涝性的差异与其抵御活性氧自由基(ROS)损伤能力的强弱、渗透调节能力的强弱有直接关系。