The Deamidase of Groundnut Plants (Arachis hypogaea)

The deamidase enzyme system present in extracts of groundnutplant tissues has been studied. The distribution of the enzymewithin the different organs of the plant were determined, andsome of the properties of the enzyme present in leaf extractsare recorded. From its substrate specificity the enzyme is probablybest regarded as a -methyleneglutaininase, although it catalysesthe hydrolysis of glutamine at about one-fifth of the rate of-methyleneglutamine. The enzyme may play an important role inthe over-all nitrogen metabolism of the plant, as well as controllingthe relative concentrations of -methyleneglutamine and -methyleneglutamicacid in the different organs. The properties of the enzyme havebeen compared with those recorded in the literature of glutaminasesand asparaginases, and certain common features are apparent.The new deamidase was, however, more stable to certain denaturingtreatments than were the other types of deamidase.     

RNA Polymerase II Activity in Developing and Germinating Cowpea Seeds

RNA polymerase II was partially purified from germinating cowpeaseeds and characterized. RNA polymerase II activity per seedwas low soon after flowering but increased thereafter, reachinga maximum after about two weeks. Upon desiccation, the activitydecreased and was very low in quiescent seeds. After germination,the activity increased rapidly. (Received July 23, 1990; Accepted November 30, 1990)     

The Response of Groundnut (Arachis hypogaea L.) to Timing of Irrigation

A timing-of-irrigation experiment was conducted in controlled-environmentglasshouses, in which a finite quantity of water was appliedto four stands of groundnut (Arachis hypogaea L.) at differentstages of the growing season. Irrigation schedules were broadlydivided into two periods; sowing to pod initiation and pod initiationto final harvest. Within these periods two levels of soil moisturedeficit were imposed by withholding or applying limited amountsof irrigation at regular intervals. Shoot dry matter yields were hardly affected but pod yieldswere more than 4-fold lower in early- than in late-irrigatedstands. Thermal time was used to separate the effects of temperatureand water stress on developmental processes. The degree-dayrequirement for peg initiation was similar in all treatmentsbut late-irrigation delayed pod development by about 200 °Cd.The effect of timing of irrigation on pod yield operated mainlythrough its influence on the duration of pod production, whichwas closely linked to the rate and duration of canopy expansionlate in the season. The insensitivity of pod yield to earlymoisture deficits reflected the extreme plasticity of growthand development in groundnut, since most processes resumed ratessimilar to the pre-stress levels in early-irrigated stands oncestress was released. Key words: Groundnut, irrigation, growth, development     

Characterization of Two Strains of Cowpea Mild Mottle Virus Naturally Infecting Groundnut (Arachis hypogaea L.) in India

Two viruses were isolated from commercial groundnut plants showing mild mottle (MM) and severe mottle (SM) symptoms in the Rayalaseema area of Andhra Pradesh State, India. The host range of both the isolates was restricted to Fabaceae. The physical properties of both isolates were: DEP 10^-6 to 10^-7. TIP 70–85 C and LIV 5–8 days. Partially purified virus preparations contained slightly flexuous filamentous particles. In ELISA and gel diffusion tests both isolates reacted similarly with anusera to the carlaviruses cowpea mild mottle, cassia mild mosaic and potato M. Particle morphology. sedimentation coefficient, and estimated sizes of the coat proteins and RNAs gave additional evidence that the viruses were carlaviruses. Bemisia labaci transmitted only the MM isolate and the two isolates also differed in electrophoretic mobility of intact particles and amino acid composition of the coat proteins. The isolates are identified as distinct strains of cowpea mild mottle virus.     

Absence of Root Hairs in Non-Nodulating Groundnut, Arachis hypogaea L.

Root hairs observed at the site of lateral root emergence innodulating groundnut cultivars were found to be absent in non-nodulatinggroundnut lines. In a segregating F₂-population of the crossNC 17 x PI 259747 a strong association was observed betweenthe presence of root hairs and nodulation, and the absence ofroot hairs and non-nodulation. Key words: Root hairs, Arachis hypogaea, Non-nodulation     

Jasmonic Acid-Mediated-Induced Resistance in Groundnut (Arachis hypogaea L.) Against Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae)

Jasmonic acid (JA) acts as a signal molecule to induce resistance in plants against herbivores and its levels are elevated in plants after wounding or insect damage. Groundnut is an important crop in many tropical and subtropical regions worldwide, but there is surprisingly little knowledge on its induced defenses against herbivores. The effect of JA as a spray on induced resistance in three groundnut genotypes, namely, ICGV 86699 (resistant), NCAc 343 (resistant), and TMV 2 (susceptible), against Helicoverpa armigera was studied. The activity of oxidative enzymes [peroxidase (POD) and polyphenol oxidase (PPO)] and the amounts of other host plant defense components [total phenols, hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and protein content] were recorded at 24, 48, 72, and 96 h after pretreatment (1 day) with JA followed by infestation with H. armigera (PJA + HIN) and H. armigera infestation with simultaneous JA application (HIN + JA) to understand the consequences of induced resistance in groundnut. The plant damage, larval survival, and larval weights were also recorded. There was a significant increase in POD and PPO activities and in the amounts of total phenols, H₂O₂, MDA, and proteins in PJA + HIN- and JA + HIN-treated plants as compared to the plants treated with JA and infested with H. armigera individually and to untreated control plants. Among all the genotypes, the strongest induction of defense was observed in the ICGV 86699 genotype. It is concluded that pretreatment with JA and its application during low levels of insect infestation can increase the levels of host plant resistance against herbivorous insects and reduce the pest-associated losses in groundnut.     

Detection of a Luteovirus in Groundnut Rosette Diseased Groundnuts (Arachis hypogaea) by Enzyme-linked Immunosorbent Assay and Immunoelectron Microscopy

In groundnut rosette diseased groundnut plants collected near Zaria, Nigeria, a luteovirus was detected by ELISA and ISEM. In ELISA only beet western yellows virus antiserum reacted, while in ISEM luteovirus particles were trapped by antisera beet western yellows virus, potato leafroll virus, pea leafroll virus and barley yellow dwarf virus. The data are in agreement with the interpretation that the assistor of groundnut rosette virus is possibly a member of the luteovirus group.     

ATP Synthesis in Cell-Free Extracts of Peanut (Arachis hypogaea L.) Seeds

Cell-free extracts of peanut (Arachis hypogaea L., cv. Shulamit)seeds, incubated with various substrates, synthesized ATP. Significantsynthesis occurred in the presence of AMP + PEP, NADH₂ + PEPand NAD + PEP. When the activities were examined in extractsprepared with 0.3 M mannitol, the rates were 0.6, 0.1 and 0.04nmol min^–1 mg^–1 protein, respectively. The activitiesunder such conditions were linear with time up to 90 min incubationat 30 °C. In the presence of PEP + NADH₂ there was a higherspecific activity in extracts from non-dormant seeds than fromdormant seeds. No such difference was found when PEP + AMP orNAD + PEP was used as the substrate. The temperature dependenceof the activity showed a relatively high energy of activation(Ea) for AMP + PEP and a low one if NADH₂ + PEP or NAD + PEPwas used as substrate. In buffer extracts of seeds ATP was synthesizedin the presence of the above-mentioned substrate combinationsbut the rate of activity exhibited a lag phase at the earlytime of incubation, after which higher rates of activities (ascompared with mannitol extracts) were obtained. The activitieswere Co⁺-dependent, with a K_m of about 0.7 mM. In the bufferextracts relatively high activities of adenylate kinase (EC2.7.4.3 [EC] (AK) and pyruvate kinase (EC 2.7.1.50 [EC] ) (PK) were found.AK was stimulated by ethephon (ethylene). This effect is temperature-dependentand occurs in both directions: in the presence of ADP (ATP +AMP) as well as if ATP + AMP is used as substrate to synthesizeADP. PK is Co⁺-dependent, and unaffected by ethephon. Both activitieswere stimulated by malonate. Key words: Adenylate Kinase, Arachis hypogaea, ATP synthesis, Peanut, Pyruvate kinase, Seed     

Proteolytic and Trypsin Inhibitor Activity in Germinating Jojoba Seeds (Simmondsia chinensis)

Changes in proteolytic activity (aminopeptidase, carboxypeptidase, endopeptidase) were followed during germination (imbibition through seedling development) in extracts from cotyledons of jojoba seeds (Simmondsia chinensis). After imbibition, the cotyledons contained high levels of sulfhydryl aminopeptidase activity (APA) but low levels of serine carboxypeptidase activity (CPA). CPA increased with germination through the apparent loss of a CPA inhibitor substance in the seed. Curves showing changes in endopeptidase activity (EPA) assayed at pH 4, 5, 6, 7, and 8 during germination were distinctly different. EPA at pH 4, 5, 6, and 7 showed characteristics of sulfhydryl enzymes while activity at pH 8 was probably due to a serine type enzyme. EPA at pH 6 was inhibited early in germination by one or more substances in the seed. Activities at pH 5 and later at pH 6 were the highest of all EPA throughout germination and increases in these activities were associated with a rapid loss of protein from the cotyledons of the developing seedling.     

Changes in the Activity of Acetyl CoA Carboxylase in Germinating and Ripening Sunflower Seeds

Activity of acetyl CoA carboxylase was determined in germinating and maturing sunflower (Helianthus annuus L.) cv. Rum Sun Record seeds. A constant decrease was observed in germi nating embryos. Exposure of etioplasts to light intensity of 500 (74 mW . cm^?2) lux for different time intervals decreased the activity of the enzyme in the embryos. A reverse trend was observed in ripening embryos where the ATP-Pi exchange rate was found to be directly correlated to the activity of acetyl CoA carboxylase.     

Mitochondrial Arginase Activity from Cotyledons of Developing and Germinating Seeds of Vicia faba L

Differential and sucrose density gradient centrifugation established that about 80% of the total arginase activity (EC 3.5.3.1) in cotyledons of germinating broad bean seeds (Vicia faba L.) was present in the mitochondrial fraction. The mitochondrial arginase activity was enhanced considerably by exposure to osmotic shock, by freezing and thawing, or by Triton X-100 treatment. About 10% of the total arginase activity was recovered from the 40,000g supernatant fraction. During seed maturation, arginase activity in the cotyledons decreased to about one-third of its maximal activity, while increasing over 10-fold during subsequent germination. The time courses of mitochondrial arginase, succinate oxidase, and succinate dehydrogenase activities differed considerably during germination.     

水稻胚乳甲壳素结合蛋白(ES-CBP)在发育种子中的组织专一性累积及其在萌发时的降解(英文)

免设印迹表明,水稻 ES—CBP(en—dosperm chitin—binding Protein)是胚乳专一性蛋白。蛋白休用NaCl提取后再用TritonX—100提取,所得的两个组份在作免疫印迹时,均能与抗ES—CBP的抗血清起反应,表明这种细胞器的衬质(matrix)和膜部分部有ES—CBP存在。免疫印迹还表明,在开花后7d(7DPA)的水稻种于胚乳中已经累积了相当多的 ES—CBP。在7～30 DPA之问.ES—CBP在胚乳总蛋白中的相对水平随着种子发育而下降。这些结果表明,ES—CBP在7DPA以前的胚乳中的累积是相对活跃的。水稻种子贮藏蛋白在7DPA以后累积最快,这时胚乳中已经累积了相当多的ES—CBP。种子萌发后2d(2DPG)时,ES—CBP已有明显的降解。到7DPG,胚乳中只剩下少量的甲壳素结合蛋白。ES—CBP这样的累积和降解模式支持了该甲壳素结合蛋白是水稻胚乳中蛋白体组织者的假说。     

Responses to Saturation Deficit in a Stand of Groundnut (Arachis hypogaea L.). 2. Growth and Development

Stands of groundnut were grown in four glasshouses with themaximum saturation deficit (D) of the air limited to 1.0, 2.0,2.5 or 3.0 kPa. The soil was near field capacity when plantsemerged and no water was applied thereafter. In a fifth glasshouse,a stand was grown at low D on soil irrigated to field capacityevery few days. Developmental processes such as timing of flowering, peggingand pod formation were unaffected by D, but the numbers of branches,flowers and pegs were reduced in the drier treatments. Measurementsduring the first 30 d showed that in the drier treatments leafgrowth was reduced, and the partitioning of dry matter intoroots was enhanced. In the unirrigated stands, dry matter production in shoots wasreduced by 40 per cent as the maximum D increased from 1.0 to3.0 kPa. Growth was affected through reductions both in leafarea (and therefore light interception) and in the productivityper unit of light intercepted. These responses to D and soilwater were linked to changes in bulk water potential of leaves. Productivity per unit of water transpired (q) decreased withincreasing D. The product of q and the mean daytime value ofthe difference in vapour pressure between leaf and air was moreconservative than q, and ranged from 3.1 to 5.6 g kPa kg^–1. Groundnut, Arachis hypogaea L., saturation deficit, growth, development, light interception, water use efficiency     

Activity of acid and alkaline phosphatases (intracellular and extracellular) in rhyzosphere fungi from Arachis hypogaea (Papiloneaceae)

The potential role of the fungi, isolated from the peanut rhizosphere, in the production of extracellular and intracellular acid and alkaline phosphatase, was evaluated in vitro. Acid and alkaline extracellular phosphatases showed the highest activities, and the Penicillium species were the most efficient in their production. The correlation analysis showed that extracellular acid and intracellular acid phosphatase produced by Aspergillus niger A. terreus, Penicillium sp. y P. brevicompactum were negatively correlated; while the extracellular and intracellular phosphatase activities, were positively correlated. The extracellular acid phosphatase activities produced in vitro by majority of fungi assayed, were not correlated with the acid phosphatase activity present in the peanut soil rhizosphere. Nevertheless, the extracellular alkaline phosphatase activities produced in vitro, were negatively correlated with the extracellular alkaline phosphatase activities present in the rhizosphere. The ability of phosphatase production by fungi isolated from peanut rhizosphere suggests they have great potential to contribute to the P mineralization in this zone.     

Response of Groundnut (Arachis hypogaea L.) to inoculation withRhizobium strains isolated from wild arboreal legumes

Summary The rhizobial strain isolated from wild arboreal legumes viz.Butea monosperma, Glyricidia sepium andAcacia nilotica effectively increased nodulation, shoot weight, pod weight, nitrogenase activity and also showed high competitive ability as compared to the homologous strains NC92 and G2 as well as chemical and absolute controls in groundnut. Thus, the findings of present study open a new field for exploring superior rhizobia from wild legumes, which can be used for improving the yield of cultivated legumes.

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Réponse de l'arachide (Arachis hypogaea L.) à l'inoculation par des souches de Rhizobium isolées de légumes arboricoles sauvages

Résumé Les souches rhizobiennes isolées de légumes sauvages arboricoles commeButea monosperma,Glyricidia sepium etAcacia nilotica ont effectivement augmenté la nodulation, le poids de la racine, le poids des cosses, l'activité de nitrogénase. Elles ont aussi montré une aptitude à la forte compétition par comparaison avec les souches homologues NC92 et G2 de même qu'un contrôle chimique et absolu de l'arachide. Aussi, les résultats de la présente étude ouvrent un nouveau champ pour l'exploration des rhizobia supérieurs de légumes sauvages, qui peuvent être utilisés pour l'amélioration du rendement de légumes cultivés.

     

Responses to Saturation Deficit in a Stand of Groundnut (Arachis hypogaea L.) 1. Water Use

Stands of groundnut were grown in computer-controlled glasshouseson water stored in an undisturbed soil profile. The maximumsaturation vapour pressure deficit (D) of the air was either1.0, 2.0, 2.5, or 3.0 kPa, and the mean air temperature was27 °C. Transpiration (E), determined from the soil water balance, wasstrongly dependent on D, because D influenced both the fractionof incident solar radiation intercepted by foliage (f) and thetranspiration rate per unit f (E/f). When D exceeded 2 kPa,canopy expansion was restricted and f reduced during early growth,but differences in f diminished as the canopies closed. E/fincreased with D, implying that any restriction of transpirationthrough stomatal closure at large D was outweighted by a steeperhumidity gradient from leaf to air. In all treatments E/f decreased as the soil profile dried. Saturationdeficit per se had little influence on the proportional reductionin E/f with time, even though soil water deficit was considerablygreater at large D. This lack of response occurred because plantscompensated for the greater evaporative demand by extractinglarger amounts of water from deep in the profile. Groundnut, Arachis hypogaea L., humidity, rooting depth, transpiration     

花生成熟花粉的超微结构

花生（Arachis hypogaea L．）成熟花粉为二细胞型,具3个萌发沟,少数有4个。外壁呈蜂窝状。花粉壁由覆盖层、基粒棒、外壁内层及内壁构成。线粒体嵴密集、相互平行,脂体被粗面内质网包围。粗面内质网与外核膜相连,亦与线粒体相连。高尔基体甚少。营养核无核仁及染色质,与生殖细胞相连形成雄性生殖单位（male germ unit）。生殖细胞锤形、有壁,见一末端延伸成长尾状（长8μm）。细胞质含核糖体、线粒体、微管,未见体。在有些生殖细胞核内观察到具双层膜、少量嵴及深色内含物的球形结构,其米来源及本质尚不知,有待进一步研究确定。     

The Influence of Temperature and Water Deficits on the Partitioning of Dry Matter in Groundnut (Arachis hypogaea L.)

The partitioning of dry matter to stems, leaves and pods ofgroundnut was examined as a function of mean air temperatureand water stress. Different levels of stress were imposed bygrowing plants on stored moisture at five different mean temperaturesbetween 19 °C and 31 °C and at four levels of saturationvapour pressure deficit. Stands of plants were grown in controlledenvironment glasshouses. The ratio of pod to shoot weight (PWR) was greatest at 22 °Cand decreased from 0.28 to 0.04 as temperature increased to31 °C. PWR was closely related to the number of pods longerthan 5.0 mm but negatively correlated with stem weight ratio.In general, water stress had a minor influence on PWR althoughpeg and pod production were stimulated in five of the nine treatments.Mild water stress promoted peg and pod production because reproductivegrowth was less affected than the growth of leaves and stems,the major sinks early in the reproductive phase. In one treatment,mild water stress increased PWR by a factor of 2.2 indicatingthat when adequate water is supplied to relieve a mild stress,PWR can be greatly increased. Key words: Temperature, Water deficit, Partitioning, Groundnut