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1.
张萌  阎君  朱为民  郭世荣 《西北植物学报》2016,36(12):2469-2476
采用营养液栽培方式,以4个硝酸盐含量有显著差异的菠菜品种为材料,测定其生长指标(株高、主根长、株幅、柄长、干鲜重和叶面积)、光合色素(叶绿素a、b及类胡萝卜素)含量、光合作用参数(实际光化学量子产率、表观光合电子传递率、光化学猝灭系数、非光化学猝灭系数)、硝酸根吸收速率和硝酸还原酶活性等,研究不同硝酸盐含量基因型品种的生理差异。结果显示:(1)不同基因型菠菜叶片的硝酸盐含量始终存在着巨大差异,且硝酸盐含量与生物量之间没有明显的相关关系,在同样的栽培条件下,生物量大的品种并不代表其硝酸盐含量低。(2)高硝酸盐含量基因型菠菜品种的光合色素含量较低,光合作用效率较差,硝酸吸收速率较高,硝酸还原酶活性较低;而低硝酸盐含量基因型菠菜品种的光合色素含量较高,光合作用较强,硝酸吸收速率较低,硝酸还原酶活性较高。(3)低硝酸盐含量基因型品种SL 06 13的综合评价最好,可以作为选育低硝酸含量菠菜品种的材料。研究表明,菠菜硝酸盐含量的基因型差异产生的原因可能是受硝酸盐吸收和转运的共同影响。  相似文献   

2.
施锌对石灰性褐土上小白菜光合作用及保护酶活性的影响   总被引:5,自引:0,他引:5  
通过田间试验的方法,采用30(低锌)、75(中锌)和120kg/hm2ZnSO4(高锌)3个施锌水平,研究施锌对山西省石灰性褐土上小白菜叶片叶绿素含量、净光合速率、硝酸还原酶(NR)活性、抗氧化酶活性及丙二醛(MDA)含量的影响.结果表明:随着施锌量的提高,小白菜叶片各叶绿素组分含量、总叶绿素含量、净光合速率和NR活性均呈先升后降的变化趋势,并均以中锌处理最大,且中、高锌处理显著高于对照(不施锌);小白菜叶片过氧化物酶(POD)和过氧化氢酶(CAT)活性也呈先升后降的趋势,而超氧化物歧化酶(SOD)活性持续增加,CAT、POD和SOD活性分别在低锌、中锌和高锌处理时达到最大值,所有施锌处理的3种保护酶活性均显著高于缺锌对照;各处理小白菜叶片MDA含量随着施锌量增大而逐渐降低,且所有施锌处理均显著低于缺锌对照.研究发现,施锌能有效增强石灰性褐土上小白菜叶片光合能力和氮同化能力,显著提高其抗氧化酶系活性,并以75kg/hm2ZnSO4效果最佳.  相似文献   

3.
采用营养液水培方法,研究了低氧胁迫下外源γ-氨基丁酸(GABA)对甜瓜幼苗光合色素含量、光合作用及叶绿素荧光参数的影响.结果表明:低氧胁迫导致甜瓜幼苗光合色素含量显著下降,光合作用降低;外源GABA能显著提高正常通气和低氧胁迫下甜瓜幼苗的光合色素含量、净光合速率、气孔导度、胞间CO2浓度、CO2羧化效率、最大光化学效率、光化学猝灭系数、表观光合电子传递速率和PSⅡ光合电子传递量子效率,而气孔限制值、初始荧光和非光化学猝灭系数显著降低,GABA在低氧胁迫下的提高效果更明显;同时添加GABA和GABA转氨酶抑制剂γ-乙烯基-γ-氨基丁酸(VGB)处理显著降低了低氧胁迫下GABA对甜瓜幼苗光合特性的缓解效果.  相似文献   

4.
采用高温处理前用0.6%NaCl浇灌小白菜的方法,通过测定高温胁迫下小白菜(Brassica campestris ssp.chinensis L.)叶片的PSI、PSII活性,净光合速率和叶绿素荧光参数,研究了NaCl预处理对小白菜光合特性的影响。结果表明,高温胁迫下,NaCl预处理组小白菜的PSII活性、净光合速率、Fm和Fv/Fm值等均高于CK组,Fo值低于CK组。说明NaCl预处理可在一定程度上缓解小白菜的高温胁迫,保护光合系统免受高温的损害,增强高温胁迫下小白菜叶片的光能转化效率。  相似文献   

5.
采用营养液水培方法,通过外源施加H2S供体NaHS(100μmol/L),研究了信号分子H2S对100mmol/L NO3-胁迫下番茄幼苗生理生化特性的影响。结果表明:(1)NO3-胁迫下,随着处理时间的延长,番茄幼苗的株高、根长、鲜重和干重显著降低,叶绿素(a、b)含量、净光合速率、气孔导度、蒸腾速率均显著降低,而胞间CO2浓度以及丙二醛(MDA)、H2O2含量增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性显著降低,抗坏血酸(AsA)和还原性谷胱甘肽(GSH)含量显著降低。(2)与NO3-胁迫处理相比,外源NaHS处理1、3、5d后,番茄幼苗的株高、根长、鲜重和干重显著增加,叶绿素(a、b)含量、净光合速率、气孔导度、蒸腾速率均显著升高,而胞间CO2浓度显著降低;MDA和H2O2含量降低,SOD、POD、CAT和APX活性显著增强,AsA和GSH含量显著增加,而且幼苗的硝酸还原酶、谷氨酰胺合成酶、谷氨酸合酶的活性显著增强;L-半胱氨酸脱巯基酶活性和内源H2S含量增加。研究认为,外源H2S可能通过提高抗氧化物酶的活性和增加抗氧化物质含量来缓解NO3-对番茄幼苗造成的伤害,从而增强其对NO3-胁迫耐性。  相似文献   

6.
采用营养液水培方法,研究了低氧胁迫下外源γ-氨基丁酸(GABA)对甜瓜幼苗光合色素含量、光合作用及叶绿素荧光参数的影响.结果表明:低氧胁迫导致甜瓜幼苗光合色素含量显著下降,光合作用降低;外源GABA能显著提高正常通气和低氧胁迫下甜瓜幼苗的光合色素含量、净光合速率、气孔导度、胞间CO2浓度、CO2羧化效率、最大光化学效率、光化学猝灭系数、表观光合电子传递速率和PSⅡ光合电子传递量子效率,而气孔限制值、初始荧光和非光化学猝灭系数显著降低,GABA在低氧胁迫下的提高效果更明显;同时添加GABA和GABA转氨酶抑制剂γ-乙烯基-γ-氨基丁酸(VGB)处理显著降低了低氧胁迫下GABA对甜瓜幼苗光合特性的缓解效果.  相似文献   

7.
以番茄品种‘合作908’幼苗为材料,研究了80 mmol/L硝酸钙胁迫下叶面喷施10 mg/L硫酸铈对番茄幼苗生长、叶片抗氧化酶活性及光合性能的缓解效应。结果显示:硝酸钙胁迫导致番茄幼苗的株高、茎粗、鲜重、地上和地下部干重显著降低,叶片SOD、POD、CAT活性减弱,净光合速率、气孔导度、蒸腾速率以及胞间CO2浓度均显著下降,而MDA含量和质膜透性显著升高;与硝酸钙胁迫处理相比,叶面喷施硫酸铈处理对硝酸钙胁迫下的番茄幼苗株高、茎粗、鲜重和干重等营养生长具有不同程度的促进作用,同时显著提高叶片SOD、POD和CAT活性,有效降低叶片MDA含量和细胞膜透性,并且显著提高了叶片净光合速率、气孔导度、蒸腾速率。研究表明,叶面喷施硫酸铈可诱导增强硝酸钙胁迫下番茄幼苗叶片的抗氧化酶活性,有效降低膜脂过氧化程度,维持较高水平的光合性能,从而一定程度上缓解硝酸钙胁迫对番茄幼苗生长造成的伤害,增强其耐受盐胁迫的能力。  相似文献   

8.
渗透胁迫对番木瓜若干生理性状的影响   总被引:5,自引:0,他引:5  
研究了渗透胁迫下番木瓜幼苗的细胞伤害程度、净光合速率的变化及其与气孔导度之间的关系。试验结果表明渗透胁迫导致番木瓜幼苗叶片细胞相对电导率和MDA含量分别增加了 1 1 .72倍和 1 1 .0 7倍、可溶性蛋白质及叶绿素含量则分别下降了 5 7.3 %和 5 7.6%、POD及SOD活性先升后降 ,但SOD活性降低时间早于POD ,渗透胁迫降低了番木瓜的净光合速率和叶片水势 ,轻度胁迫时 (处理前期 )气孔导度的限制是导致净光合速率降低的主要原因 ,重度胁迫时(处理后期 )叶肉光合能力的下降是引起净光合速率降低的主要原因。  相似文献   

9.
研究了热带落叶乔木大叶桃花心木(Swietenia macrophylla)在施氮和去除子叶后幼苗叶片的硝酸还原酶活性(NRA)变化.结果表明,在非施氮(对照)条件下,NRA随着幼苗叶片的发育先升高后降低;施氮后幼苗叶片NRA在各取样时期(除35 d外)均显著高于非施氮处理(P < 0.05),并随着取样时期的延续,叶片NRA逐渐降低.在幼苗发育的不同时期去除子叶,4周后,叶片NRA均显著升高(P < 0.05).  相似文献   

10.
以东京四照花(Cornus hongkongensis subsp.tonkinensis)幼苗为试验材料,考察施用外源CaCl2对3‰海盐处理条件下东京四照花幼苗生长、光合色素含量、光合气体交换参数、渗透调节物质含量等生理指标的变化特征,探讨外源CaCl2对盐胁迫伤害的缓解效果及生理机制。结果表明:(1)3‰海盐胁迫处理下,东京四照花幼苗生长受到显著抑制,其叶片丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性以及渗透调节物质可溶性糖、可溶性蛋白及脯氨酸的含量均显著增加,而叶片光合色素含量、胞间二氧化碳浓度(Ci)、净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)显著降低。(2)3‰海盐和CaCl2复合处理下,施用低浓度(10~20 mmol·L-1)外源CaCl2降低了幼苗的盐害率和死亡率,促进了幼苗的叶片和植株生物量积累,但降低了可溶性蛋白含量;中低浓度外源CaCl2<...  相似文献   

11.
Li XZ  Oaks A 《Plant physiology》1994,106(3):1145-1149
Both light and NO3- are necessary for the appearance of nitrate reductase (NR) activity (NRA) in photosynthetic tissues. To define the light effect more precisely, we examined the response to light/dark transitions on NRA, NR protein (NRP), and NR mRNA in 6-d-old maize (Zea mays cv W64A x W182E) seedlings that had been grown in a light/dark regime for 5 d and then induced with 5 mM KNO3 for 24 h. The decay of NRA and NR mRNA in the shoot was immediate, but there were only minor changes in NRP during the initial 4 h in the dark. In root tissues, in contrast, there was a 4-h delay in the loss of NRA, NRP, and NR mRNA after transfer to the dark. When the seedlings were returned to light after a 2-h interval in the dark, shoot NRA reached 92% of the initial levels within 30 min of illumination. These results indicate that in the shoots (a) NR message production requires light and (b) the NRP that appears with light treatment and that is active is inactivated in the dark. The NRP can be reactivated when the light is turned on after short periods of darkness (2 h). Root tissues, on the other hand, probably respond to the supply of photosynthetically produced metabolites rather than to immediate products of the light reactions of photosynthesis.  相似文献   

12.
Regulation by the active form of phytochrome (PFR) and the effect of Ca2+ was examined with nitrate reductase (NR) in etiolated cucumber ( Cucumis sativus cv. Beilpuig). Nitrate reductase activity (NRA) was studied in excised cotyledons of cucumber seedlings grown in distilled water and in darkness for seven days at 24 ± 0.5°C. All experiments were performed in the dark and a dim green safelight was used during analyses. In etiolated cucumber cotyledons NRA was induced by nitrate and a brief irradiation (15 min) with red light (R) resulted in 62% increase in NRA. This effect was nullified when R was followed immediately by a brief (5 min) far-red light (FR). NRA also showed a semidian (12 h) rhythmicity. Both PFR, and nitrate effects were age dependent. Calcium seemed to be involved since the phytochrome effect was only observed when calcium was supplied in the external solution. The effect of R on NRA depended on the period of calcium nitrate incubation. An external supply of calcium ionophore mimicked the effect of R and, if supplied to R-irradiated cotyledons, produced a higher NR level than that caused by R alone. This suggested that intracellular free calcium was involved.  相似文献   

13.
Phaseolus vulgaris L. cv. Kinghorn Wax seedlings, supplied with nutrient solution containing either 0 or 5 mM nitrate as sole N source, were exposed to 0.25 μl/l NO2 for 6 hr each day for 10 days at continuous photosynthetic photon flux (PPF) of 100, 300, 500 or 700 μmol m−2 sec−1. There was a significant interaction of PPF and nitrate. Shoot and root dry weights increased with increasing PPFs only when nitrate was supplied. The main effects of NO2 on plant growth were significant; none of the interactions involving NO2 were significant. Exposure to NO2 decreased shoot and root dry weight in both the presence and absence of nutrient N and at all PPF levels. All interactions were significant for in vitro leaf nitrate reductase activity (NRA), which increased markedly at PPFs above 100 μmol m−2 sec−1 when nitrate was supplied. Treatment with NO2 strongly inhibited enzyme activity in the presence of nitrate, particularly at the 300 μmol m−2 sec−1 PPF level. These experiments demonstrated that PPF level does not modify the effect of NO2 on growth but does have a major effect on NRA and on NO2 effects on NRA in the presence of nutrient nitrate.  相似文献   

14.
Effect of nitrate availability on nitrate reduction was examined in inter-connected ramets of invasive clonal plant Eichhornia crassipes grown with two nitrate supply regimes during different clonal growth stage. Increase of nitrate availability accelerated nitrate reductase activity (NRA) in parent and offspring ramets of E. crassipes, and there was greatly different pattern in inter-connected ramets during clonal growth stage. Leaf NRA was lower in offspring than that in parent ramets in phase 1, while significantly higher leaf NRA in offspring ramets was detected during phase 2. The results indicated NRA in inter-connected ramets of E. crassipes was highly dependent on nitrate availability and growth stage.  相似文献   

15.
The effect of supplying either nitrate or ammonium on nitrate reductase activity (NRA) was investigated in Brassica napus seedlings. In roots, nitrate reductase activity (NRA) increased as a function of nitrate content in tissues and decreased when ammonium was the sole nitrogen source. Conversely, in the shoots (comprising the cotyledons and hypocotyl), NRA was shown to be independent of nitrate content. Moreover, when ammonium was supplied as the sole nitrogen source, NRA in the shoots was surprisingly higher than under nitrate supply and increased as a function of the tissue ammonium content. Under 15 mM of exogenous ammonium, the NRA was up to 2.5-fold higher than under nitrate supply after 6 d of culture. The NR mRNA accumulation under ammonium nutrition was 2-fold higher than under nitrate supply. The activation state of NR in shoots was especially high compared with roots: from nearly 80% under nitrate supply it reached 94% under ammonium. This high NR activation state under ammonium supply could be the consequence of the slight acidification observed in the shoot tissue. The effect of ammonium on NRA was only observed in cotyledons and when more than 3 mM ammonium was supplied. No such NRA increase was evident in the roots or in foliar discs. Addition of 1 mM nitrate under ammonium nutrition halved NRA and decreased the ammonium content in shoots. Thus, this unusual NRA was restricted to seedling cotyledons when nitrate was lacking in the nitrogen source.  相似文献   

16.
随营养液中No_3~-浓度升高,叶片内No_3~-总量、代谢库大小(NIPS)及硝酸还原酶(NR)活性均升高,其中MPS与NK活性呈同步变化;No_3~-浓度达2.0mmol/L时,两者趋于稳值;若再增加NO_3~-浓度,则被吸收的NO_3~-积累于液泡中,而代谢库中NO_3~-含量(MPS)与NO_3~-总量之比有一定程度降低。低氮(NO_3~-浓度为1.0 mmol/L)情况下,反应液中无NO_3~-时,叶片内NR活性品种间有差异,但在50 mmol/L NO_3~-反应液中则品种间无差异;NK活性高的品种鲁麦8号及品种321叶内有大的NO_3~-代谢库,反应液中NO_3~-对NR活性刺激程度低,代谢库NO_3~-含量与叶NO_3~-总量之比高,而叶组织长时间反应过程中其NR活性衰减速率低。  相似文献   

17.
Amino compounds (1 mM, pH 5) were given prior to, together with, or after the addition of nitrate to study their effect on nitrate uptake and in vivo nitrate reductase activity (NRA) in roots of Phaseolus vulgaris. The effect of amino compounds varied with the amino species, the nitrate status of the plant (induced vs uninduced) and the aspect of nitrate utilization. Cysteine inhibited the nitrate uptake rate and root NRA under all conditions tested. NRA in uninduced roots was stimulated by tryptophan, and arginine inhibited NRA under all conditions tested. Uptake was inhibited by aspartate and glutamate and stimulated by leucine when these amino compounds were given prior to or after completion of the apparent induction of nitrate uptake. In the presence of β-alanine and tryptophan, induction of uptake was accelerated.  相似文献   

18.
Nitrogen fixing plants of lucerne (Medicago sativa L. cv. Aragón) were grown in a glasshouse for three months in the absence of nitrate, and then supplied with 5 mM KNO3 for a week. In control (non-nitrate fed) plants, nitrate reductase activity (NRA EC 1.6.6.1) was detected only in nodules. After nitrate supply, root NRA showed a transient increase. Shoot NRA increased with time, paralleling changes in nitrate distribution; stem NRA represented nearly 50% of total NRA in plant tissues. Total nitrogen, expressed on a dry weight basis, tended to decrease in shoots upon nitrate supply. Bacteroid NRA (EC 1.7.99.4) showed a great variation depending on Rhizobium meliloti strains, ranging from 5 to 40% of total plant NRA. However, different Rhizobium strains did not give different results in terms of plant growth parameters, nitrate or organic nitrogen content.  相似文献   

19.
土壤干旱胁迫对黄栌叶片光合作用的影响   总被引:9,自引:0,他引:9  
Liu G  Zhang GC  Liu X 《应用生态学报》2010,21(7):1697-1701
采用CIRAS-2型便携式光合作用系统,设置充足供水、轻度、中度和重度胁迫4种土壤水分处理,研究土壤干旱和强光胁迫对3年生黄栌苗木叶片光合作用的影响.结果表明:土壤干旱胁迫对黄栌叶片的光合性能参数影响显著,随着土壤水分胁迫的加剧,黄栌叶片的光合速率、蒸腾速率和光量子效率明显降低,光补偿点增高,水分利用效率在轻度水分胁迫(土壤相对含水量60%~65%)下最高;在强光(有效辐射强度1000~1800μmol.m-2.s-1)范围内,叶片光合速率和水分利用效率均较高,而对弱光的光能吸收和光量子效率较低,并随土壤水分胁迫加剧明显下降.  相似文献   

20.
When nitrate is the only nitrogen source, Neurospora crassa's nitrate reductase (NR) shows endogenous oscillations in its nitrate reductase activity (NRA) on a circadian time scale. These NRA oscillations can be observed in darkness or continuous light conditions and also in a frq(9) mutant in which no functional FRQ protein is formed. Even in a white-collar-1 knockout mutant, NRA oscillations have been observed, although with a highly reduced amplitude. This indicates that the NRA oscillations are not a simple output rhythm of the white-collar-driven frq oscillator but may be generated by another oscillator that contains the nit-3 autoregulatory negative feedback loop as a part. In this negative feedback loop, a product in the reaction chain catalyzed by nitrate reductase, probably glutamine, induces repression of the nitrate reductase gene and thus downregulates its own production. This is the first example of an endogenous, nutritionally induced daily rhythm with known molecular components that is observed in the absence of an intact FRQ protein.  相似文献   

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