土壤紧实胁迫对黄瓜叶片光合作用及叶绿素荧光参数的影响

紧实是温室土壤的疲劳症状之一,它对作物的生长、产量及养分吸收均有影响。本试验以容重为指标,用盆栽试验模拟温室土壤的物理疲劳症,研究了土壤紧实胁迫对黄瓜叶片光合作用及叶绿素荧光参数的影响,探讨温室土壤物理疲劳对黄瓜叶片光合作用产生影响的机理。结果表明,土壤紧实胁迫条件下黄瓜叶片的净光合速率（Pn）、气孔导度(Gs)及蒸腾速率(Tr)下降,而胞间CO2浓度（Ci）却增大,最终导致叶片干物质的累积量减少,第一雌花节位降低,果实发育提早。叶片的叶绿素含量减少,光合活性（Fv）、光系统Ⅱ（PSⅡ）反应中心的电子传递活性（Fm/Fo）、光能的最大转化效率（Fv/Fm）及PSⅡ的潜在活性（Fv/Fo）降低以及PSⅡ的光能利用率下降是紧实胁迫条件下黄瓜叶片光合作用减弱的原因。     

高硼胁迫对油菜光合作用的影响研究

硼是作物必需的一种微量元素，土壤缺硼会导致作物生长不良，产量低下［1］，因此硼肥的施用已成为当前提高油菜作物产量与品质的有效农业措施。     

氮素供应水平对小白菜生长和硝酸盐积累的影响

蔬菜是一种易富集硝酸盐的作物。研究表明，人体摄入的硝酸盐有72％-94％来自蔬菜。虽然硝酸盐本身对人体无害或毒害性相对较低，但吸收过多的硝酸盐可能会对人体健康构成潜在的威胁协引。为了降低蔬菜可食部分的硝酸盐含量，改善蔬菜的卫生品质，保护人类健康，国内外学者自60年代以来就比较系统地研究了蔬菜硝酸盐的积累与分布规律。小白菜是人们食用的主要蔬菜之一，因此，如何降低小白菜的硝酸盐积累、提高其营养及卫生品质已经成为蔬菜安全研究的一大热点问题。     

春季气象条件对温州蜜柑光合作用的影响

通过对柑桔光合作用与气象条件的对比观测,采用数理统计方法,分析、处理改良干重法测定的春季柑桔树的光合速率资料,试图建立春季气象条件对温州蜜柑光合作用影响的模式。     

含硝化抑制剂DMPP氮肥对小白菜硝酸盐累积和营养品质的影响

新型硝化抑制剂3,4-二甲基吡唑磷酸盐(3,4-dimethylpyrazole phosphate,DMPP)对叶菜类蔬菜(如菠菜)硝酸盐的累积有明显的抑制作用[1-5],但其与氮肥一起造粒形成的新型氮肥在蔬菜上的研究还少有报道.我们以常规氮肥(NH4HCO3,urea,ASN)作对比,就新型含硝化抑制剂氮肥(ASN DMPP)在典型菜地正常施肥条件下对降低小白菜硝酸盐累积及营养品质的影响进行了研究,以期为提高蔬菜品质提供依据.     

稀土对缓解油菜镉胁迫的研究

长期利用污水灌溉、污泥改良土壤以及化学农药和化肥的不合理施用,会使农用土壤受到重金属不同程度的污染[1] ,且以重金属镉(Cd)污染最为普遍关注.     

小白菜硝酸还原酶基因的克隆与初步鉴定

蔬菜是一种易于富集硝酸盐的植物性食物，人体摄入的硝酸盐大部分（70％～80％）来自蔬菜。然而，我国蔬菜生产中氮肥用量迅速提高，造成了蔬菜，特别是喜氮的叶菜类蔬菜硝酸盐含量过高。不同蔬菜硝酸盐含量存在很大差异，同一种蔬菜不同品种体内硝酸盐含量也存在差异。不同器官累积硝酸盐的能力不同，硝酸盐累积取决于硝态氮的吸收与同化的结果。     

镁对烟草生长及叶片叶绿素荧光参数的影响

通过水培试验,研究了不同镁素水平对烟草生长、叶片叶绿素含量及叶绿素荧光参数的影响,为烟草优质栽培和镁肥的合理施用提供理论依据。结果表明营养液中镁浓度在2～4 mmol/L时,烤烟的干物质积累显著高于其它处理,最适宜烟株的生长,镁浓度过高或过低都会抑制烟株的生长;营养液中镁浓度在0～2 mmol/L范围内,烟草叶片叶绿素含量随镁浓度的升高而逐渐升高,但高于2 mmol/L时,烟草叶片叶绿素的含量逐渐下降;营养液中镁浓度在8 mmol/L时,烟草叶片量子产量（EQY）光合电子传递速率（ETR）、非光化学猝灭（NPQ）均达到最高。烟草叶片对强光有最大的适应性,缺镁和高镁均能导致烟草量子产量降低,光合电子传递受阻,减少对过剩的激发能的耗散,使植株对强光的保护性调节能力降低。     

Effect of methanol on soybean photosynthesis and chlorophyll

Recently, an increase in the growth and yield of C3 plants in arid environments due to foliar application of methanol has been reported. The mechanism for these changes is not clear as little information is available on the changes in photosynthesis and chlorophyll content of plants caused by methanol application. The objective of this study was to measure the net photosynthesis (PN) and chlorophyll (CHL‐a, b) formation in soybean [Glycine max (L.) Merr] by foliar applications of methanol at the pod‐filling R5) stage. No changes were found in PN or CHL content with 0, 25, or 50% (v/v) methanol during 1, 2 or 3 weekly applications. Seed weight, seed yield, and pod number (per plant) were significantly higher for plants treated with methanol. A single application of methanol (25%) resulted in the highest increase in soybean growth and yield.     

冰核细菌对低温胁迫下枇杷光合参数和叶绿素荧光参数的影响

冻害是影响和限制枇杷生产和发展的主要因素。本试验以"早钟6号"枇杷为试材,采用人工降温的方法,测定接种冰核细菌后,枇杷叶片光合参数和叶绿素荧光动力学参数变化。结果显示:冰核细菌的存在能显著降低低温胁迫下枇杷叶片的Pn、Fm、Fv、Fv/Fo、Fv/Fm和水分利用效率,说明冰核细菌加重了低温对枇杷叶片光合机构的破坏性,加重冻害发生。在接种冰核细菌条件下,-3℃比-1℃Pn、Fm、Fo、Fv、Fv/Fo和Fv/Fm降低更显著且时间提前,说明温度愈低,冰核细菌对光合系统的破坏愈重且冻害发生时间提前。另外,Tr与冰核细菌的存在无显著相关性。     

不同肥料对生姜产量及叶片光合作用和叶绿素荧光特性的影响

为探讨生物有机肥对生姜的增产效果,以‘莱芜大姜’为试材,研究了不同肥料配比对生姜生长及叶片光合作用和叶绿素荧光特性的影响。结果表明,增施生物有机肥可显著提高生姜叶片色素含量及净光合速率,促进生姜生长,且随生长的进行,生物有机肥的作用效果日趋明显。生姜旺盛生长期(9月22日),生物有机肥处理的生姜叶片叶绿素含量分别比普通有机肥及化肥处理高5.5%和13.1%;叶片净光合速率分别高8.2%和17.8%。尽管各处理生姜叶片的光化学效率在午间高温强光下均降低,但生物有机肥处理的生姜叶片原初光能转换效率（Fv/Fm）、光合电子传递量子效率（φPSⅡ）和光化学猝灭系数（qP）较高,而非光化学猝灭系数（NPQ）较低,表明增施生物有机肥可提高生姜叶片光能利用效率。生物有机肥处理的生姜产量分别比普通有机肥及化肥处理高9%和24%左右。     

不同施氮量对结缕草生长及光合荧光特性的影响

研究不同氮肥用量(N 0、3和9 g·m-2)对结缕草生理、光合及荧光特性的影响。结果表明,3和9 g·m-2氮肥均使结缕草地上及地下生物量增加;提高了结缕草叶片叶绿素含量、净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、水分利用率(WUE)、PSⅡ最大光能转换效率(Fv/Fm)、光系统Ⅱ(PSⅡ)的活性(Fv/Fo)、实际光化学量子效率(ΦPSII)、光化学淬灭系数(qP),降低了非光化学淬灭系数(qN)。3 g·m-2氮肥处理效果好于9 g·m-2氮肥处理,对结缕草的生长和发育的促进作用更加明显。     

添加物对镉、锌、铅污染土壤上小白菜的生长和养分吸收的影响

A pot experiment was carried out to study the effects of two amendments, lime and calcium magnesium phosphate, on the growth and Cd,Pd,Zn,Cu,Mn,Fe,N,P and K uptake of pakchoi (Brassica chinensis) in a Cd,Pb and Zn polluted acid soil in the southern part of China. The growth of pakchoi was apparently improved by lime and calcium magnesium phosphate application, the uptake of Cd,Pb,Cu and Zn by pakchoi was significantly depressed and the symptom caused by heavy metals pollution was eliminated. Meanwhile, the absorption of N,K and Mn was also inhibited by these amendments. Soil pH was the main factor controlling the uptake of the heavy metals by pakchoi. This suggests that lime and calcium magnesium phosphate could be used as effective amendments for eliminating the toxicity of heavy metals to the vegetable and inhibiting their absorption by the crop.     

施水对本氏针茅光合作用和叶绿素荧光特征的影响

 通过利用短期施水代替降雨的方法,研究长期干旱条件下突然施水对本氏针茅光合特性的影响。结果表明:施水后,本氏针茅的叶水势得到恢复,RuBP羧化酶活性提高,表观量子效率、羧化速率和最大光合能力明显增加,限制光合作用的气孔因素和非气孔因素得到缓解。同时,本氏针茅的光化学活性在施水后部分恢复,光量子产量和热耗散能力明显提高。不同水分条件下,本氏针茅叶片的叶绿素荧光光诱导过程存在较大的差异,施水条件下,叶片的光合速率、气孔导度、实际光化学效率和非光化学淬灭上升速率较快,而持续干旱条件下叶片的光诱导速率较慢。     

Combined effects of phosphorus nutrition and elevated carbon dioxide concentration on chlorophyll fluorescence,photosynthesis, and nutrient efficiency of cotton

To examine the combined effects of phosphorus (P) nutrition and CO₂ on photosynthesis, chlorophyll fluorescence (CF), and nutrient utilization and uptake, two controlled‐environment experiments were conducted using 0.01, 0.05 and 0.20 mM external phosphate each at ambient and elevated CO₂ (aCO₂: 400 and eCO₂: 800 µmol mol^?1, respectively). The CF parameters were affected more by P nutrition than by CO₂ treatment. Photoinhibition of photosystem II (PSII) was due to increased minimal CF (Fo′) and decreased maximal CF (Fm′), and efficiency of energy harvesting (Fv′/Fm′). In addition, reduced electron transport rate (ETR), the quantum yield of PSII (Φ_PSII) and CO₂ assimilation ( ), and overall photochemical quenching in the P‐deficient leaves led to reduction in the efficiency of energy transfer to the PSII reaction center. Stimulation in the Φ_PSII/ and photorespiration (ETR/P_net) was found under P deficiency, whereas the opposite was the case under CO₂ enrichment. On average, photosynthetic rate (P_net) and stomatal conductance declined by 50–53% at 0.05 mM P and by 70–72% at 0.01 mM P as compared to the 0.20 mM P treatment. However, P deficiency, especially at eCO₂, tended to increase the intrinsic water‐use efficiency. In the P‐deficient plants, the decline in the P and N utilization efficiency (up to 91%) of biomass production was mainly associated with greater reduction in the biomass relative to the tissue P concentration as the P supply was reduced. However, it was significantly stimulated by eCO₂ especially at higher P supply. The CO₂ × P interaction was observed for some parameters such as Fo′, Fm′, P utilization efficiencies of photosynthesis and biomass production that might be attributed to the irresponsiveness of these parameters to eCO₂ under low P treatment. Thus, P deficiency limited the beneficial effect of eCO₂. A close relationship between total biomass and photosynthesis with the P and N utilization or uptake efficiencies was found. The P utilization efficiency of P_net appeared to be stable across a range of leaf P concentrations, whereas the N‐utilization efficiency markedly increased with leaf P and differed between CO₂ levels. An apparent effect of both the treatments (P and CO₂) on N‐uptake and utilization efficiency also indicated the alteration in N acquisition and assimilation in cotton plants.     

Leaf photosynthesis,chlorophyll fluorescence and ion content of barley (Hordeum vulgare) in response to salinity

Eight barley genotypes contrasting in their salinity tolerance were assessed for their chlorophyll fluorescence, photosynthetic performance, lipid peroxidation level and ionic content. A pot experiment was conducted in Borj-Cedria (Tunisia), in a wire house with a glass roof to avoid rainfall. The assay consisted of three treatments (0, 100 and 200 mM NaCl) with eight barley genotypes following a completely randomized design. Each pot was considered as one replicate and nine replicates were used for each genotype and treatment. The salt-tolerant genotypes Kerkna and Tichedrett recorded the highest tolerance for photosynthesis and potassium accumulation, whereas the susceptible genotypes were mostly affected at severe salinity. Contrasting behavior was noted for fluorescence attributes, while PSII yield was unchanged reflecting good protection against photodamage. Photosynthetic performance, enhanced water use efficiency, maintained leaf K⁺ and oxidative defense remain the key components for tolerance mechanisms. Salt-tolerant barley could be suitable for management of salt-affected soils.     

缺磷胁迫下草甘膦对抗草甘膦大豆幼苗光合作用和叶绿素荧光参数的影响1

为探明缺磷胁迫下草甘膦对抗草甘膦大豆（RR1）幼苗叶片光合作用和叶绿素荧光参数的影响,采用溶液培养方法,在大豆长出真叶时进行缺磷胁迫,第二复叶完全展开时进行草甘膦处理,5d后测定各生理指标。结果表明, 相对于正常供磷条件的清水处理,缺磷胁迫下4.98 mL/L草甘膦处理的大豆叶片净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、最大荧光（Fm）、PSⅡ最大光化学效率（Fv/Fm）、PSⅡ的有效量子产量［Y(Ⅱ)］、PSⅡ非调节性能量耗散的量子产量［Y(NO)］、最大电子传递速率（ETRmax）和半饱和光强（Ik）均呈下降趋势。而气孔限制值（Ls）、叶绿素a（Chl a）、叶绿素b（Chl b）、叶绿素a/b（Chl a/b）、类胡萝卜素（Car）、总叶绿素（Chl）含量和PSⅡ调节性能量耗散的量子产量［Y(NPQ)］均呈升高趋势。说明缺磷胁迫条件下喷施草甘膦显著降低了抗草甘膦大豆的光合速率。缺磷引起的气孔因素可能是导致RR大豆光合速率下降的主要原因,而光合速率的下降导致其PSⅡ反应中心的开放程度降低,活性减弱,参与CO2固定的电子较少,光化学效率较低。