CO_2浓度升高对杉木幼苗生长及其光合特性和养分含量的影响

以杉木优良无性系‘洋061’幼苗为材料,设置常规CO_2浓度400μL·L~(-1)(对照组)和CO_2加富浓度800μL·L~(-1)(处理组)两个处理,研究CO_2浓度加富对杉木幼苗生长、根系形态特征、光合生理以及养分含量的影响,以明确杉木优良无性系对CO_2浓度升高的响应特征,为杉木苗木高效培育提供理论依据。结果表明:(1)CO_2加富能显著促进杉木幼苗生物量的积累和苗高的生长,并显著促进杉木根系生长,其根长、根系表面积、根系体积和根系直径分别较对照增加14.60%、28.26%、41.98%和14.70%。(2)CO_2加富能促进杉木叶片类胡萝卜素含量显著增加,使杉木叶片净光合速率(P_n)、胞间二氧化碳浓度(C_i)和水分利用效率(WUE)分别较对照显著提高51.03%、14.13%和151.20%,并使气孔导度(G_s)和蒸腾速率(T_r)分别显著下降58.72%和44.00%。(3)CO_2加富使杉木叶片最大荧光(F_m)、可变荧光(F_v)、PSⅡ潜在光化学效率(F_v/F_o)、PSⅡ实际光化学效率(Φ_(PSⅡ))和光化学淬灭系数(qP)分别较对照显著增加11.48%、11.25%、6.33%、20.38%和30.34%,且不同处理间差异显著,非光化学淬灭系数(NPQ)较对照显著下降21.90%(P0.05),但对初始荧光(F_o)和PSⅡ最大光化学效率(F_v/F_m)无显著影响(P0.05)。(4)CO_2加富处理显著增加植株钙元素的含量,并显著降低植株磷元素的含量。研究认为,短期CO_2加富处理可通过增加光合色素含量,提高叶片净光合速率和光能利用效率,进而增强叶片光合能力,同时促进根系生长,增强植物对养分吸收的能力,最终促进杉木幼苗的生长。     

内源GSH参与低温胁迫下外源NO对黄瓜幼苗叶片光合作用的调控

为探讨还原型谷胱甘肽(GSH)参与低温(10℃/6℃)胁迫下一氧化氮(NO)对黄瓜幼苗叶片光合及荧光作用的调节作用,该研究以‘津研4号’黄瓜幼苗为试材,于四叶一心时置光周期14 h/10 h、昼夜温度25℃/20℃光照培养箱内,叶面预处理分别为:双蒸水(对照)、GSH合成酶抑制剂(BSO,丁硫氨酸亚砜胺)、NADPH合成酶抑制剂(6-AN,6-氨基烟酰胺),8 h后再喷施NO供体亚硝基铁氰化钠(SNP),于第1次喷施药剂24 h后昼夜温度降至10℃/6℃,低温胁迫24 h后测定叶片细胞膜透性、气体交换参数、叶绿素荧光等各项指标。结果显示:(1)与CK相比,SNP处理显著提高了黄瓜幼苗叶片相对含水量、叶绿素含量、净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)、最大光化学量子产量(F_v/F_m)、实际光化学效率(Φ_(PSⅡ))、非光化学猝灭系数(NPQ)、光化学猝灭系数(qP)、表观光合电子传递系数(ETR)及NO含量,显著降低叶片胞间CO_2浓度(C_i)、电解质渗漏率、丙二醛(MDA)含量、非调节性能量耗散量子产量Y_(NO)。(2)SNP处理可保持较高的荧光产额,使快速叶绿素荧光诱导曲线JIP相逐渐升高,而BSO+SNP、6-AN+SNP处理显著降低了SNP的作用效果;SNP处理黄瓜幼苗叶片PSⅡ最大光化学效率(φ_(Po))、PSⅡ反应中心吸收光能用于电子传递的量子产额(φ_(Eo))、捕获激子将电子传递到电子传递链Q_A~-下游其他电子受体的概率(ψ_o)、与PSⅡ反应中心受体侧性能有关的荧光参数包括氧气释放复合体(OEC)活性状态(F_(O-K))、Q_A被还原能力(F_(K-J))、Q_B(含快还原PQ库)被还原能力(F_(J-I))和慢还原PQ库被还原能力(F_(I-P))以及单位受光面积有活性反应中心数量(RC/CS)等均显著高于CK,而与反应中心关闭有关的荧光参数Q_A被还原最大速率(M_o)和J相相对可变荧光(V_J)均显著低于CK。(3)BSO+SNP、6-AN+SNP处理也削弱了SNP的这些作用效果。研究表明,在低温胁迫条件下,内源GSH参与了外源NO增强黄瓜幼苗叶片相对含水量、缓解膜脂过氧化、稳定PSⅡ和促进PSⅡ反应中心电子传递链供受体侧的电子传递能力,从而提高黄瓜幼苗耐冷性。     

盐碱胁迫对垂丝海棠光合作用及渗透调节物质的影响

该研究以2年生垂丝海棠(Malus halliana Koehne)实生苗为研究材料,设置盐胁迫(NaCl)、盐碱混合胁迫(NaCl+NaHCO_3,1∶1)和碱胁迫(NaHCO_3)3类处理,并以清水作为对照(CK),通过盆栽的方法测定不同时间点垂丝海棠叶片光合色素含量、光合作用参数、叶绿素荧光参数、相对电导率及渗透调节物质含量的变化,以探讨不同盐碱胁迫下垂丝海棠的生理响应特性。结果表明:(1)3种盐碱胁迫条件下,随着胁迫时间的延长,垂丝海棠植株叶片光合色素(叶绿素a、b和类胡萝卜素)的合成受到抑制,且以碱胁迫处理下降低最为明显,碱胁迫40 d后叶绿素a(Chl a)、叶绿素b(Chl b)及类胡萝卜素(Car)分别降低67.18%、68.90%和64.67%。(2)垂丝海棠叶片的净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)在3种盐碱胁迫下均显著低于CK,而碱处理、盐碱混合处理下的胞间CO_2浓度(C_i),在胁迫20 d时较CK分别升高137.13%和77.66%,胁迫40 d后,则分别降低56.82%和51.89%。(3)随胁迫时间的延长,3种盐碱胁迫处理下的垂丝海棠植株叶片PSⅡ实际光化学效率(Φ_(PSⅡ))、最大荧光(F_m)、光化学淬灭系数(qP)和最大光化学效率(F_v/F_m)均受到抑制,但碱胁迫下的初始荧光(F_0)与盐处理和盐碱混合处理的非光化学淬灭系数(qN)则表现为升高趋势,且于胁迫40 d后,较CK分别升高60.98%、90.70%和99.15%。(4)胁迫40 d后,盐处理、碱处理及盐碱混合处理植株叶片的相对电导率(REC)分别比CK升高了9.39%、35.07%和29.32%,同时各处理胁迫40 d后的可溶性糖(SS)、脯氨酸(Pro)、有机酸(OA)显著高于CK,且OA对盐碱混合处理更为敏感,其含量显著高于盐处理和碱处理。(5)3种胁迫对垂丝海棠生长和光合的抑制作用表现为碱处理盐碱混合处理盐处理。研究发现,垂丝海棠植株的光合作用受到3种盐碱胁迫的显著抑制,并以碱胁迫的影响程度更大,但其能通过渗透调节物质来应对胁迫,有效缓解盐碱胁迫的伤害,增强自身耐盐碱能力。     

NaCl胁迫对祁连山野生黄瑞香叶片光合叶绿素荧光特性的影响

以4片真叶黄瑞香幼苗为材料,设置不同浓度(0、50、100、150、200mmol·L~(-1))NaCl胁迫处理,采用温室砂培实验系统考察了其幼苗叶绿素含量、叶绿素荧光参数及气体交换参数等光合生理指标的变化。结果表明:(1)在正常环境条件下(对照),黄瑞香叶片净光合速率(P_n)、气孔导度(G_s)的日变化曲线呈双峰型,蒸腾速率(T_r)日变化曲线呈单峰型;较高浓度(100mmol·L~(-1))NaCl胁迫改变了黄瑞香叶片光合特性日变化曲线,导致其P_n、T_r、G_s日变化曲线整体下降,而胞间CO_2浓度(Ci)日变化曲线整体上升。(2)低浓度(50mmol·L~(-1))NaCl胁迫对黄瑞香叶片叶绿素含量及其比值无显著影响,但较高浓度(100mmol·L~(-1))NaCl胁迫则使叶绿素含量显著下降,其比值下降则较平缓。(3)较高浓度(100mmol·L~(-1))NaCl胁迫使得黄瑞香叶片最大荧光(F_m)、PSⅡ最大光化学效率(F_v/F_m)、PSⅡ光下最大捕光效率(F_v′/F_m′)、光化学荧光猝灭系数(qP)、PSⅡ实际光化学效率(Φ_(PSⅡ))均显著下降,却使其初始荧光(F_0)和非光化学猝灭(NPQ)显著上升。研究发现,随着盐胁迫浓度的增加,引起黄瑞香光合速率下降的主要原因是非气孔因素;在轻度NaCl胁迫下黄瑞香有较强的忍耐性,而重度NaCl胁迫则显著降低了叶片的光合机构活性,加剧了光抑制程度,从而严重限制了其叶片的光合作用效率。     

不同耐铝型杉木幼苗叶片抗氧化系统对铝胁迫的响应特征

为探讨铝胁迫对杉木抗坏血酸-谷胱甘肽(AsA-GSH)循环的影响,明确AsA-GSH循环在杉木耐铝性中的作用,以耐铝(YX26)和铝敏感型(YX5)杉木家系为材料,分析了铝胁迫对不同耐铝型杉木叶片氧化损伤、抗氧化酶活性和AsA-GSH循环系统的影响。结果表明:(1)铝胁迫显著增加杉木叶片丙二醛(MDA)含量,而且YX5叶片中MDA含量增幅显著大于YX26。(2)铝胁迫不同程度增加了2个杉木家系叶片过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和单脱氢抗坏血酸还原酶(MDAR)活性以及抗坏血酸(AsA)、脱氢抗坏血酸(DHA)、还原型谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSG)含量,而且除AsA含量外,铝胁迫下YX26中上述酶活性和非酶性抗氧化剂含量的增幅均大于YX5。(3)铝胁迫下YX5叶片中过氧化氢酶(CAT)和脱氢抗坏血酸还原酶(DHAR)的活性受到显著抑制,而YX26中这两个酶的活性却有所增加,且YX26中的DHAR活性显著高于对照。(4)铝胁迫抑制了2个杉木家系超氧化物歧化酶(SOD)活性,但YX26中SOD活性的降幅小于YX5。研究认为,铝胁迫下通过维持AsA-GSH循环酶活性和非酶性抗氧化系统的高效运转,增强自身活性氧清除能力是耐铝型杉木家系具有较强铝耐能力的生理基础。     

盐胁迫对甜樱桃砧木生理特性及光合荧光参数的影响

以1年生甜樱桃砧木‘吉塞拉6号’和‘考特’幼苗为材料,采用盆栽试验,研究不同浓度NaCl(0、50、100、150 mmol·L^(-1))处理对其主要渗透调节物质、抗氧化酶活性、光合特性以及叶绿素荧光参数的影响,探究甜樱桃砧木对盐胁迫响应的生理机制。结果表明:(1)NaCl处理促进了甜樱桃砧木叶片中可溶性糖、可溶性蛋白和脯氨酸等渗透调节物质的积累。(2)随着NaCl处理浓度的升高,甜樱桃砧木叶片中SOD活性呈现升高趋势,而POD活性表现出先升高后降低趋势。(3)随着NaCl处理浓度的升高,甜樱桃砧木叶片的净光合速率(P_(n))、气孔导度(G_(s))逐渐降低,而胞间CO_(2)浓度(C i)逐渐升高,非气孔限制为甜樱桃砧木叶片P_(n)下降的主要因素。(4)NaCl处理抑制了甜樱桃砧木叶片的最大光化学效率(F_(v)/F_(m))、光化学淬灭系数(q P)和电子传递效率(ETR),增加了非光化学淬灭系数(NPQ)。研究发现,盐胁迫破坏了甜樱桃砧木的光合机构,抑制了电子传递速率和光化学量子效率,降低了对光能的利用率,导致光合速率降低;甜樱桃砧木在盐胁迫条件下主要通过增加渗透调节物质含量和提高抗氧化酶活性来缓解渗透胁迫并降低氧化损伤,从而提高对盐胁迫的适应能力;‘吉塞拉6号’在盐胁迫条件下表现出更强的适应能力,其耐盐性更强;甜樱桃砧木在高于100 mmol·L^(-1)NaCl处理时表现出明显受害症状。     

铝毒胁迫诱导菜豆柠檬酸的分泌与累积

水培试验结果表明 ,铝毒诱导菜豆柠檬酸的分泌与累积存在着显著的基因型差异 .Al3 + 浓度 <5 0 μmol·L-1时 ,柠檬酸分泌量随Al3 + 浓度的增大而增加 ;Al3 + 浓度在 5 0～ 80 μmol·L-1时 ,柠檬酸分泌量随Al3 + 浓度的增大而减小 .不同菜豆基因型以G1984 2的柠檬酸分泌量最大 ,单位干重Al吸收量最小 .铝毒胁迫时 ,不同菜豆基因型叶片柠檬酸累积量无明显差异 ,根系柠檬酸累积量为G1984 2 >AFR >ZPV >G5 2 73.菜豆柠檬酸分泌量缺P处理 <铝毒胁迫 ,5 0 μmol·L-1LaCl3 不能诱导菜豆分泌柠檬酸 ,表明柠檬酸的分泌与累积是菜豆抗铝毒胁迫的重要生理反应     

氮沉降和磷添加对杉木光合及叶绿素荧光特征的影响

为探讨杉木(Cunninghamia lanceolata)光合及叶绿素荧光参数在大气氮沉降和磷添加情况下的变化, 实验以10 龄杉木为研究对象, 共设9 个处理水平: 低氮(N30: 30 kg·ha-1·a-1), 高氮(N60: 60 kg·ha-1·a-1), 低磷(P20: 20 mg·kg-1), 高磷(P40: 40 mg·kg-1), 低氮低磷(N30 + P20), 低氮高磷(N30 + P40), 高氮低磷(N60 + P20), 高氮高磷(N60 + P40)和对照处理组(CK)。结果表明: 在夏季, 氮磷添加对杉木的最大净光合速率(Pn max)无显著影响。单独添加氮、磷都抑制了杉木的最大荧光产量(Fm)、初始荧光产量(F0)、PSII 潜在活性(Fv/F0)值; 单独添加磷促进了杉木的叶色值(SPAD); 在磷添加情况下, 低氮增加了杉木的Fm, 高氮增加了杉木的SPAD 值, 降低了杉木的非光化学淬灭系数(qN)值。在秋季, 单独添加氮促进了杉木的最大净光合速率。单独添加氮、磷抑制了杉木的SPAD 值。在磷添加情况下, 氮沉降增加了杉木的SPAD值, 降低了杉木的F0 值。夏季杉木叶片N 含量与SPAD呈显著正相关(p<0.01), 秋季杉木叶片N 含量与SPAD和光化学淬灭系数(qP)呈显著负相关(p<0.05), 而与Fm 和F0 呈显著正相关(p<0.05)。     

酸性土壤上缺磷和铝毒对大豆生长的交互作用

以7个磷效率不同的大豆基因型为材料,通过土壤盆栽试验进行石灰和磷肥处理,研究酸性土壤上缺磷和铝毒对大豆生长的交互影响及其基因型差异.结果表明：缺磷和铝毒是酸性土壤上同时存在的影响大豆生长的主要障碍因子,其中铝毒对大豆生长的限制更为严重;缺磷和铝毒对酸性土壤上大豆生长的影响具有显著的交互作用.同时施用石灰（降低铝毒）和磷肥（提高磷有效性）比单施石灰或单施磷肥处理对大豆生长的促进效果更显著;缺磷和铝毒对大豆磷吸收的影响远大于对氮、钾吸收的影响.合理种植大豆对酸性土壤具有较好的改良作用.同时施用石灰［1.103 g Ca(OH)₂·kg^-1土］和磷肥（2.018 g KH₂PO₄·kg^-1土）可使酸性土壤pH值平均提高38.4%,交换性铝含量降低96.3%,有效磷含量提高3223.8％.种植磷高效大豆基因型比磷低效大豆基因型对酸性土壤的改良效果更好.     

车前对铝胁迫生理响应的研究

为探讨车前(Plantago asiatica)对铝胁迫的耐受特性及生理机理,在不同铝浓度及胁迫时间下,对其叶片的渗透调节物质、膜脂过氧化程度和体内保护酶系统进行了研究。结果表明,低浓度铝处理对车前的生理指标无明显影响。随着铝浓度的升高,叶片脯氨酸、可溶性糖、可溶性蛋白质含量呈先升高后下降趋势,细胞质膜透性显著增大、MDA含量显著增加。500 mg L–1的Al3+处理,车前叶片的SOD、CAT、POD活性均明显提高。因此,在铝胁迫下,野生草本植物车前能通过体内的生理保护机制来减少Al胁迫,表现出较强的耐铝特性。     

微生物铝毒和耐铝机制的研究现状

铝是地球上含量最为丰富的金属元素 ,在酸性条件下 ,主要以Al3 存在。Al3 作为一种严重的环境毒剂 ,已经在众多模式生物中所证明。近年来 ,许多生物学家已日益注意到铝毒和耐铝性在环境科学与生命科学领域的重要性。结合研究工作 ,综述了微生物铝毒害和耐铝的机制。微生物通过①增强分泌有机酸与Al3 螯合 ,②超表达Mg2 通道蛋白 ,增强细胞转运吸收Mg2 ,③通过线粒体ATPase和液泡ATPase协同作用将Al3 隔离于液泡内 ,以及④通过氧化胁迫改变、调节Al3 毒害和耐铝性 ,减缓Al3 对细胞的毒害。     

Aluminum ions inhibit phospholipase D in a microtubule-dependent manner.

Aluminum is a highly cytotoxic metal to plants, but the molecular base and the primary target of Al toxicity are still unknown. The most important physiological consequence of Al toxicity is a cessation of root growth and changes in root morphology suggesting a role of the root cytoskeleton as a target structure. The important role of phospholipid degrading enzyme phospholipase D in regulation of cytoskeleton remodelling in both animal and plant organisms is now evident. Both the phospholipid pathway and the cytoskeleton are influenced by Al(3+), but their relationship with Al stress remains to be explored. Therefore, we tested the possibility that Al stress could be sensed by plants through microtubules in close interaction with phospholipases. We have shown that Al(3+) reduced the formation of phosphatidic acid in vivo, inhibited activity of phosphatidylinositol-4,5-bisphosphate-dependent phospholipase D in vitro and that the phosphatidic acid production is modified by microtubule dynamics.     

Protecting Cell Walls from Binding Aluminum by Organic Acids Contributes to Aluminum Resistance

Aluminum-induced secretion of organic acids from the root apex has been demonstrated to be one major AI resistance mechanism in plants. However, whether the organic acid concentration is high enough to detoxify AI in the growth medium is frequently questioned. The genotypes of AI-resistant wheat, Cassia tora L. and buckwheat secrete malate, citrate and oxalate, respectively. In the present study we found that at a 35% inhibition of root elongation, the AI activities in the solution were 10, 20, and 50 μM with the corresponding malate, citrate, and oxalate exudation at the rates of 15, 20 and 21 nmol/cm2 per 12 h, respectively, for the above three plant species. When exogenous organic acids were added to ameliorate AI toxicity, twofold and eightfold higher oxalate and malate concentrations were required to produce the equal effect by citrate. After the root apical cell walls were isolated and preincubated in 1 mM malate, oxalate or citrate solution overnight, the total amount of AI adsorbed to the cell walls all decreased significantly to a similar level, implying that these organic acids own an equal ability to protect the cell walls from binding AI. These findings suggest that protection of cell walls from binding AI by organic acids may contribute significantly to AI resistance.     

Protecting Cell Walls from Binding Aluminum by Organic Acids Contributes to Aluminum Resistance

Aluminum-induced secretion of organic acids from the root apex has been demonstrated to be one major AI resistance mechanism in plants. However, whether the organic acid concentration is high enough to detoxify AI in the growth medium is frequently questioned. The genotypes of Al-resistant wheat, Cassia tora L. and buckwheat secrete malate, citrate and oxalate, respectively. In the present study we found that at a 35% inhibition of root elongation, the AI activities in the solution were 10, 20, and 50 μM with the corresponding malate, citrate, and oxalate exudation at the rates of 15, 20 and 21 nmol/cm2 per 12 h, respectively, for the above three plant species. When exogenous organic acids were added to ameliorate Al toxicity, twofold and eightfold higher oxalate and malate concentrations were required to produce the equal effect by citrate. After the root apical cell walls were isolated and preincubated in 1 mM malate, oxalate or citrate solution overnight, the total amount of AI adsorbed to the cell walls all decreased significantly to a similar level, implying that these organic acids own an equal ability to protect the cell walls from binding AI. These findings suggest that protection of cell walls from binding Al by organic acids may contribute significantly to AI resistance.     

植物地上部对铝毒的生理响应及其耐性

全世界50％以上潜在的可耕地属于酸性土壤,铝毒害是酸性土壤上植物生长最有害因素之一。近年来,为了阐明植物铝毒害及其耐性,前人已进行了大量的研究,并有一些综述性文章发表。然而,大多数文章主要综述铝对植物根系的影响及其耐性,因为根生长受抑是最早的铝毒害症状之一和溶液培养时最容易辨认的铝毒害症状。为此,本文综述了铝对植物地上部光合作用、光保护系统、水分利用效率、含水量、碳水化合物含量、矿质营养、有机酸和氮代谢的影响,并对富铝植物的解铝毒机制（铝与小分子有机酸螯合和把铝隔离在对铝不敏感的表皮细胞和液泡内）进行了综述。本文还对植物耐铝遗传学和分子生物学及今后需要研究的问题进行了讨论。     

Aluminum Uptake by Neuroblastoma Cells

Aluminum uptake studies in viable neuroblastoma cells were performed. Aluminum uptake was largely dependent on the pH of the suspension medium. At physiological pH values, cells were apparently unable to incorporate detectable amounts of aluminum in the absence of proper mediators. Aluminum uptake was enhanced as the pH decreased, attaining a plateau at about pH 6.0. In experiments with 2 x 10(6) cells/ml, pH 6.0, and 25 microM aluminum in the medium, aluminum incorporation reached saturation at 5 nmol of aluminum/mg of cellular protein, accounting for 60-70% of aluminum added. At pH 6.0, cells showed a large capacity for accumulating aluminum; about 70% of intracellular aluminum was associated with the postmitochondrial fraction. At neutral pH, application of apotransferrin seemed to facilitate aluminum translocation into cells via membrane receptors. Fatty acids were also capable of mediating aluminum uptake at neutral pH, probably by forming aluminum-fatty acid complexes. Low molecular weight aluminum chelators, e.g., citrate, inhibited aluminum uptake. Treatment of cells with energy metabolism blockers had virtually no influence on aluminum uptake, indicative of passive mechanisms. The results suggest that aluminum uptake occurs via different modes dependent on growth conditions, such as medium pH.     

番茄根边缘细胞生物学特性及铝对其活性的影响

以番茄为试材,采用悬空气法,探讨番茄根边缘细胞的生物学特性及铝对其活性的影响。结果表明,第1个番茄边缘细胞几乎与初生根同时出现,当根长到10 mm时,番茄边缘细胞达最大值(893个)。边缘细胞的活性(成活率)一直维持在93%以上。PME活性随着根的伸长有所降低。铝对番茄边缘细胞产生明显毒害,随着铝浓度和处理时间的增加,边缘细胞的活性显著降低。     

有机酸在植物解铝毒中的作用及生理机制

酸性土壤上铝毒是限制作物产量的一个重要障碍因子,具有螯合能力的有机酸在植物铝的外部排斥机制和内部耐受机制均具有重要作用,在铝的外部排斥解毒过程中,植物通过根系分泌有机酸进入根际,如柠檬酸,草酸,苹果酸等与铝形成稳定的复合体,阻止铝进入共质体,从而达到植物体外解除铝毒害效应的目的,且分泌的有机酸对铝的胁迫诱导表现出高度的专一性,分泌的关键点位于根尖,不同的物种间分泌的有机酸种类,分泌的模式及生理机理存在差异,在铝积累型植物的内部解毒过程中,有机酸与铝形成稳定的化合物,降低植物体内铝离子的生理活性,从而降低细胞内铝离子的毒害效应,如绣球花中铝与柠檬酸形成1：1的复合体,荞麦内铝与草酸形成1：3的复合体,本文就有机酸在植物忍耐和积累铝中的作用及生理机制作一简要综述。     

The Physiology, Genetics and Molecular Biology of Plant Aluminum Resistance and Toxicity

Aluminum (Al) toxicity is the primary factor limiting crop production on acidic soils (pH values of 5 or below), and because 50% of the world’s potentially arable lands are acidic, Al toxicity is a very important limitation to worldwide crop production. This review examines our current understanding of mechanisms of Al toxicity, as well as the physiological, genetic and molecular basis for Al resistance. Al resistance can be achieved by mechanisms that facilitate Al exclusion from the root apex (Al exclusion) and/or by mechanisms that confer the ability of plants to tolerate Al in the plant symplasm (Al tolerance). Compelling evidence has been presented in the literature for a resistance mechanism based on exclusion of Al due to Al-activated carboxylate release from the growing root tip. More recently, researchers have provided support for an additional Al-resistance mechanism involving internal detoxification of Al with carboxylate ligands (deprotonated organic acids) and the sequestration of the Al-carboxylate complexes in the vacuole. This is a field that is entering a phase of new discovery, as researchers are on the verge of identifying some of the genes that contribute to Al resistance in plants. The identification and characterization of Al resistance genes will not only greatly advance our understanding of Al-resistance mechanisms, but more importantly, will be the source of new molecular resources that researchers will use to develop improved crops better suited for cultivation on acid soils.     

Aluminum stress on sorghum growth and nutrient relationships

Summary Sorghum plants were grown in the greenhouse in modified Steinberg nutrient solution containing ten Al rates (0 to 297 μM) and harvested 28 days after transplanting. Top and root dry weight were not affected by added Al up to 74 μM; but decreased sharply at concentration of 148 μM and greater. Aluminum concentrations in blade 1 (recently matured blade) and plants remained constant from 0 to 297 μM added Al. Root Al concentration increased as added Al increased. No correlation existed between top dry weight and Al concentration in blade 1 or in plant. Root Al concentration was related to top dry weight and root dry weight to estimate the Al critical toxicity level. The Al critical toxicity levle in the root was 54 mmol kg⁻¹ root dry weight basis for either top or root dry weight. In blade 1 Cu concentration negatively correlated with Al while Fe and P were positively correlated. In roots Ca, Mg, Mn and Fe concentrations were negatively correlated with Al while Zn, Cu, P, and K were positively correlated with Al concentration.