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1.
超旱生小乔木梭梭对水分胁迫反应的某些生理生化特殊性(初报) 总被引：4，自引：0，他引：4
梭梭是一种超旱生同化枝植物,它具有许多不同于其它旱生植物的抗逆性质和对浸水的反应。就是和其它同化枝旱生植物相比,区别也很大。它的束缚水含量比其它旱生植物高得多;原生质水合能力甚强;细胞的渗透调节能力也比其它旱生植物强;梭梭的离体同化枝的保水力很突出,非常不容易蒸发失水;当同化枝受到严重失水胁迫时,细胞内脯氨酸积累率比其它植物低得多,几乎和某些复苏植物相似。同化枝浸水后发生的变化更为特殊,浸水50小时后,干重丧失最高可达50％,细胞中有些物质转化为不溶于水的沉淀物(可能是一种次生物)排出胞外,这可能是同化枝浸水后干重急速下降的主要原因。电导测量表明,同化枝浸水9小时以后细胞膜系统会发生巨大变化或破坏。所有这些特殊反应,可能与梭梭特有的抗性机制有关,值得作深入研究。 相似文献
2.
利用气孔导度-光合-蒸腾耦合模型(SMPT-SB),选取冬小麦关键生育期的典型日，模拟了冬小麦叶片和冠层尺度的光合与蒸腾速率日变化，并借助光合仪和涡度相关系统获得的观测数据进行了验证。研究结果表明：模型模拟的叶片和冠层尺度光合及蒸腾速率与实测值变化趋势具有较好的一致性，光合速率日均绝对误差不超过1μmol·m-2·s-1,蒸腾速率日均绝对误差不超过0.41 mmol·m-2·s-1;叶片尺度光合和蒸腾速率模拟值与实测值的决定系数R2均在0.90以上，冠层尺度也分别达到了0.96、0.88。此外，模型中水汽响应函数以f(Ds)=RH表示时，相对湿度(RH)变化较大会导致参数m值不能准确量化气孔导度(gs)的变化，从而降低模拟效果；若分时期率定m值，会大幅提高模拟精度。该模型适用于冬小麦叶片及冠层尺度的土壤-植物-大气之间水碳交换的模拟。 相似文献
3.
亚洲玉米螟感染白僵菌后组织病理学研究 总被引：2，自引：0，他引：2
本文报道不同虫龄的玉米螟幼虫感染白僵菌后的组织病理学过程。随着虫龄的增加，白僵菌侵入虫体及虫体组织病变解体的速度减慢。对１～２龄和３～４龄幼虫，白僵菌菌丝分别在２４小时和４８小时穿透体壁，并于４８小时和９６小时后虫体全部解体。而对老熟幼虫４８小时，菌丝刚能穿透体壁的表皮层，７２～９６小时染菌的组织仍保留其各自的轮廓没有解体。观察老熟幼虫可以发现：菌丝穿过体壁后，先在血淋巴中扩散，进入脂肪体并大量增殖，然后向结构较疏松的消化道、丝腺、马氏管、生殖腺侵入，使这些组织的边缘逐步变的不清，内部充满菌丝，以至细胞整体形状消失而解体；最后进入结构致密的肌肉、丝腺导管和神经组织，使这些组织的细胞边缘不清，出现间隙，整个组织空泡化。 相似文献
4.
不同种植方式对拔节期玉米冠层微环境的影响评估 总被引：2，自引：0，他引：2
种植方式是影响作物冠层内光合有效辐射、温度、湿度和CO2等微环境的重要因素。在大田条件下，分析3种不同的种植方式（P1，宽窄行170 cm + 30 cm，免耕；P2，宽窄行90 cm + 40 cm，免耕：CK，匀垄65 cm）对拔节期玉米冠层微环境的影响，以及微环境因素下玉米叶片光响应参数的变化。结果表明，方式P1中冠层光环境最好，3种模式间冠层温度差异显著，P1显著大于P2和CK；相对湿度的趋势与温度相反，表现为P1相似文献
5.
通过细胞组织学解剖方法 ,观察研究梭梭幼嫩光合枝显微结构的抗逆性特征 ,并结合 H2 O2 酶活性的测定 ,得出梭梭光合枝显微结构中有 3点与相关文献报道不同。 1是具有一层海棉组织 ,富含叶绿体 ,细胞体积相对较小 ,为不规则圆球状细胞层 ;2是退化的鳞片状叶表皮层下仍有一层细胞体积小 ,圆形 ,具有明显的细胞核 ,无叶绿体 ,排列紧密的细胞层 ;3是栅栏组织细胞具泌盐的功能 ,并有发育较好的盐结晶存在于细胞之间 ,显示出较强的抗逆特征。 相似文献
6.
以石羊河流域普遍种植的玉米品种先玉335为供试材料,设置7万株·hm-2和10万株·hm-2两种种植密度,充分灌水（W1）、轻度亏缺（W2）、中度亏缺（W3）3种水分条件,测定不同层次冠层光合有效辐射的分布并分析冠层光结构指标在生育期的变化。结果表明：大田玉米下部冠层光分布较优,光结构指标数值约为上部冠层的1.1倍,整体而言,增大种植密度（10万株·hm-2）增强了冠层光能截获能力,光合有效辐射截获量（IPAR）在34.02~39.38 MJ·m-2·d-1,光合有效辐射截获率抽穗期~灌浆期较低密度条件下升高0.40%~4.67%;种植密度增大（10万株·hm-2）引起群体尺度上光结构的明显劣化,消光系数（K）约为低密度条件下的83%,光合有效辐射在冠层内的衰减不均衡;拔节期低密度种植（7万株·hm-2）促进光结构指标的改善,随生育期推进,尤其在抽穗期密植（10万株·hm-2）时下部冠层的光合辐射利用效率降低约50%,这与作物自下而上的叶片衰老及光衰减不均衡有关;密植条件下(10万株·hm-2),水分亏缺处理导致辐射利用率平均降低3%,冠层各项指标受水分条件的影响较大。因此,为改善大田玉米冠层光结构,在密植条件下确保生育期中后期的充分供水十分重要。 相似文献
7.
以接种3个SMV株系后分别表现无症状、花叶和坏死症状的大豆品系浙A8901为材料,研究3类症状叶片的生理指标差异,包括细胞超微结构、H_2O_2积累、水杨酸(SA)含量、光合作用及细胞病毒含量。结果表明:无症状叶片细胞中除叶绿体片层结构轻微扭曲外,其它细胞结构未见异常;CeCl_3标记H_2O_2电镜观察,发现H_2O_2仅在细胞壁外侧少量积累;在接种1d后SA含量较对照显著升高。花叶症状叶片细胞中出现髓鞘状结构和多泡体结构,核膜边缘有染色质凝集现象;细胞壁外侧观察到较多H_2O_2的积累;SA含量在接种后第2 d较对照显著增加。坏死症状叶片中细胞变形严重,细胞器解体,在细胞壁外侧和细胞质中均观察到H_2O_2的大量积累;接种后第2 d SA含量较对照显著增加。三类症状叶片的光合速率、最大光能转化效率(Fv/Fm)和实际光量子效率(ΦPSⅡ)的测定发现,与对照相比均无显著变化。 相似文献
8.
黄土高原半干旱区集雨补灌玉米增产机理的研究 总被引：3，自引：1，他引：2
针对黄土高原集雨补灌旱作区农业节水的方法和途径,以玉米为试材,研究了不同水分组合处理对玉米光合作用、产量和干物质累积的影响。结果表明:各处理光合因子的日变化曲线均呈现抛物线型,各光合因子的日变化规律受光照强度影响很大;覆膜坐水结合拔节期补灌22.5 mm处理在13∶00左右之前和19∶00左右的细胞间隙CO2浓度较其它处理大,而在其它时间内较其它处理小,其它光合因子与此规律相反,表明光照强度对光合因子的日变化起着重要的作用;在整个日变化过程中,补灌处理在光照强度大的下午提高了叶片的光合速率、蒸腾速率和气孔导度,使得细胞间隙CO2浓度减少。分析各光合因子日变化中的最大值可知:在13∶00左右,覆膜坐水结合拔节期补灌22.5 mm处理、覆膜坐水结合拔节期补灌15 mm处理的光合速率分别比对照提高23.9%、15.0%,蒸腾速率分别比对照提高47.7%、17.7%;产量分别比对照提高43.02%、29.48%。拔节期补灌不仅有显著的增产效果,还可以不同程度地提高干物质累积量。 相似文献
9.
研究科尔沁沙地南缘人工林枯落物层与土壤层对该地区水文效应的影响，为该地区之后人工林的经营与恢复提供理论依据。以不同配置模式的人工林为研究对象，利用熵权法对不同配置模式的人工林水源涵养能力进行评估。对于不同配置模式中的枯落物持水量与浸水时间、枯落物吸水速率与浸水时间以及土壤入渗时间与入渗速率进行拟合，均呈现出显著的函数关系；针阔混交林模式在枯落物有效拦蓄量、土壤最大持水量、土壤有效持水量和毛管持水量中均为最大，灌木纯林最小，其它的配置模式在枯落物层和土壤层的水文过程中表现有所差异；运用相关性分析和主成分分析对林地涵养水源指标进行分析和因子筛选，最终筛选出9个指标对6种不同的配置模式进行枯落物层和土壤层水文效应进行综合评价，表明水源涵养能力最强的针阔混交林模式，并且不同配置模式中混交林在枯落物层与土壤层的整体表现都优于纯林。 相似文献
10.
银鲫消化道的组织形态学和组织化学 总被引：8，自引：0，他引：8
本文对银鲫消化道结构进行了组织学和组织化学的观察。研究结果表明，该杂食性硬骨鱼的咽后消化道是由食道，小肠前部，小肠后部组成。消化道组织分层为粘膜层，粘膜下层，肌层及外膜。食道前侧区粘膜上皮主要由鳞状上皮细胞组成，上皮表层分布有微嵴和味蕾。食道后侧区粘膜上皮由柱状细胞和粘液细胞组成。 相似文献
11.
Walter Oettmeier Klaus Masson Carl Fedtke Jörg Konze Robert R. Schmidt 《Pesticide biochemistry and physiology》1982,18(3):357-367
In chloroplasts isolated from susceptible and atrazine-resistant Amaranthus retroflexus, the inhibition of photosynthetic electron transport by various classes of herbicides has been investigated. Resistance of mutant Amaranthus is not restricted to s-triazines but also extends to uracils, 1,2,4-triazine-5-ones, and ureas. For 1,2,4-triazin-5-ones and chloroplasts of both biotypes, a correlation between inhibition of photosynthetic electron transport and the partition coefficient could be established. In the case of phenolic herbicides only modestly decreased or even higher sensitivity of chloroplasts from the resistant biotype as compared to the susceptible one could be observed. These results are confirmed by binding of radioactively labeled herbicides to chloroplasts of both plants. Specific binding of atrazine or metribuzin to resistant chloroplasts is completely abolished, and that of diuron or phenisopham diminished as compared to susceptible chloroplasts. In contrast, binding of phenolic herbicides generally is enhanced in resistant chloroplasts. Photoaffinity labeling of thylakoids from both biotypes by 2-azido-4-nitro-6-[2′,3′-3H]isobutylphenol yields almost identical labeling patterns. These results are consistent with a recently proposed model (W. Oettmeier, K. Masson, and U. Johanningmeier, Biochim. Biophys. Acta679, 376 (1982) of two different herbicide binding proteins at the reducing side of photosystem II: a 32- to 34-kdalton protein responsible for binding of triazines, triazinones, ureas, and related herbicides and a photosystem II reaction center protein for binding of phenolic herbicides. 相似文献
12.
The effects of acifluorfen and oxyfluorfen on photosynthetic electron transport reactions of pea chloroplasts were compared with those induced by paraquat and monuron. Monuron inhibited electron flow between photosystems I and II, and paraquat acted as an electron acceptor for photosystem I, promoting superoxide formation by illuminated chloroplasts. Neither acifluorfen nor oxyfluorfen at concentrations up to 50 μM affected non-cyclic electron flow or promoted superoxide formation. Both herbicides were shown to repress ferredoxin-dependent NADP+ reduction by illuminated chloroplasts. Further experiments showed that, in the presence of ferredoxin-NADP+ reductase and chloroplast membranes maintained in the dark, p-nitro diphenyl ether (DPE) herbicides promoted the rate of ferredoxin-dependent oxidation of NADPH, implying that these herbicides can accept electrons from reduced ferredoxin. The interaction between acifluorfen, ferredoxin and chloroplast membranes was examined further by following the effect of this herbicide on the peroxidation of illuminated thylakoids. Lipid peroxidation was promoted by acifluorfen, although this effect was abolished if thylakoids were washed prior to use. The effect of washing could be reversed by adding exogenous ferredoxin. These data demonstrate that interaction of DPE herbicides with photosynthetic electron transport in the vicinity of ferredoxin is necessary for light-dependent herbicide activation. 相似文献
13.
14.
The effects of paraquat and 2,4,5-T on the photochemical activities of chloroplasts from the leaves of the woody species Carissa spinarum, Maba buxifolia, Flacourtia sepiaria, Chomelia asiatica, Gymnosporia emarginata and Dodonaea viscosa were investigated by comparing the effects on isolated chloroplasts from untreated leaves with those on chloroplasts isolated from herbicide-sprayed plants. DCPIP and NADP reduction of chloroplasts incubated in paraquat or 2,4,5-T solution was inhibited, whereas that of chloroplasts isolated from most species sprayed with these herbicides was enhanced after 24 and 48 h. The enhancement was smaller or disappeared after 72 h. The cyclic and noncyclic photophosphorylation rates were suppressed in chloroplasts isolated from herbicide-treated plants, and also in those from most untreated plants incubated in the herbicide solutions. The differences in reactions of chloroplasts from herbicide-treated and untreated plants are discussed. 相似文献
15.
Atrazine [2-chloro-4-(ethylaminol-6-(isopropyl-amino)-s-triazine] resistant biotypes of lamb's quarters (Chenopodium athum L) were reported in the maize growing areas of Ontario, where the herbicide had been used fur a number of years. Field samples from four locations proved tolerant to higber than recommended rates of atrazine in controlled environment screening trials. A resistant biotype was not killed with up to 40 kg/ha atrazine. Diuron at 5 x10-5 M inhibited the Hill reaction with isolated chloroplasts of resisiant and susceptible biotypes of lamb's-quarters. However, with 10-4 M atrazine, the photochemical activity was inhibited in chloroplasts isolated from the susceptible biotype but not in chloroplasts from the resisiant biotype. With maize chloroplasts, inhibition with 10-4 M atrazine was the same as with the susceptible biotype of lamb's-quarters. These studies suggested that a new mechanism of intraspecific resistance in lamb's quarters to atrazine was involved, other than differences in uptake, translocation and metabolism reported with interspecific comparisons involving the s-triazines and other herbicides, It was also concluded that atrazine and diuron did not have precisely the same mechanism of action as photosynthetic inhibitors with lamb's-quarters, and that external and or internal structure or function of chloroplasts in relation to atrazine inhibition can vary significantly even in biotypes of the same species. 相似文献
16.
百合无症病毒对百合光合生理、酶活性及叶绿体超微结构的影响 总被引：1，自引：0，他引：1
以东方百合“西伯利亚”为试验材料,研究百合无症病毒(LSV)侵染百合对其叶片生理生化以及叶绿体超微结构的影响。检测结果表明:叶片中叶绿素a、b以及总叶绿素含量与健康对照相比分别下降了28.6%、33.3%和23.5%,净光合速率、气孔导度及胞间CO2浓度分别下降33.3%、25%和13.8%;超氧化物歧化酶(SOD)、过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)与健康对照相比,分别增加了16.6%、29.4%、16.7%和22.2%。电镜观察发现:感病植株叶绿体膨胀变形,基质片层散乱,叶绿体内淀粉粒肿大且数目增多,从而证明LSV侵染破坏叶绿体结构,影响植株的光合作用。 相似文献
17.
Faye D. Schwelitz H.C. Sikka J. Saxena G. Zweig 《Pesticide biochemistry and physiology》1974,4(4):379-385
Isolated spinach chloroplasts and Chlorella cells treated with dichlone (2,3-dichloro-1,4-naphthoquinone) exhibited morphological changes which appeared to be consistent with an alteration of protein elements in the cell. The stroma of dichlone-treated chloroplasts appeared less structured and more homogeneous than that of the control. The cell membrane in dichlone-treated Chlorella cells shrank from the cell wall and exhibited much invagination while the outer membrane of Chlorella chloroplasts appeared wavy. The changes in the cytoplasm of treated Chlorella cells closely reflected those noted in the chloroplast stroma. 相似文献
18.
Jean Marc Routaboul Franoise Nurit Patrick Ravanel Michel Tissut 《Pest management science》1990,30(2):149-158
The effects of bifenox (methyl 5-(2,4-dichlorophenoxy)-2-nitrobenzoate) and oxadiazon (5-tert-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2(3H)-one on photosynthetic activity were investigated in isolated chloroplasts, and on respiratory activity in isolated mitochondria. The global effects of these chemicals were also investigated on cucumber cotyledon pieces. It was found that, in vitro, bifenox and oxadiazon acted on cotyledon pieces as typical diphenyl ether herbicides, causing complete pigment bleaching, even at low concentrations. In addition, bifenox and oxadiazon were shown to inhibit the photosynthesis process at the chloroplast level. At concentrations of up to 40-50 μM, oxadiazon and bifenox were observed to inhibit fully the light-dependent oxygen evolution of spinach class A chloroplasts, oxadiazon acting preferentially on electron transfer at the PS II level whereas bifenox acted on the photophosphorylation process. Comparison of the amounts of herbicide needed to inhibit photosynthesis and to cause bleaching of cucumber pieces leads to the conclusion that photosynthesis inhibition by bifenox and oxadiazon is only a secondary effect. 相似文献
19.
A bird's eye review was tried to select the bio‐rational targets from known and novel plant‐specific ones for the molecular design of modern herbicides, which exhibit efficient phytotoxicity at a low‐use rate and preserve a good environment in the 21st century. In phytotoxic sites in the photosynthetic electron transport (PET) system discussed in the present article (Part 1), the generally called bleaching herbicides interfering with the biosynthesis of photosynthetic pigments, chlorophylls and carotenoids, and the biosynthesis of plastoquinone, were considered to be good models for the molecular design of modern herbicides. The PET itself was still considered as an interesting target site for new herbicides, although they need to exert their action in all green leaves of weeds to achieve herbicidal efficacy. Because these herbicides never form a tight binding with D1‐protein, their use‐rate cannot be expected to be as low as the herbicides inhibiting chlorophyll or branched amino‐acid biosynthesis. Other herbicidal targets found in chloroplasts, namely ATP and NADPH formations, have already been omitted from the worldwide biorational molecular design program of herbicides targeting the PET system. 相似文献
20.
Summary. The toxicity of potassium iodide towards bean plants ( Phaseolus vulgaris ) is greater in the light than in the dark. Treatment of leaf discs in the dark or the light reduces photosynthetic activity to the same extent, but the loss of chlorophyll is less pronounced in the dark. Iodine behaves similarly but is effective at lower concentrations. Iodide does not inhibit chlorophyll synthesis. Iodine is some 105 times as effective as iodide in inhibition of the Hill reaction in isolated chloroplasts. These results are consistent with the hypothesis that iodine toxicity is a result of intracellular oxidation to iodine.
Action herbicide de l'iodure de potassium. Effet sur la teneur en chlorophylle et la photosynthèse sur le haricot nain (Phascolus vulgaris) 相似文献
Action herbicide de l'iodure de potassium. Effet sur la teneur en chlorophylle et la photosynthèse sur le haricot nain (Phascolus vulgaris) 相似文献