Heat Shock Proteins of Pigeon Pea (Cajanus cajan)

The proteins synthesized in response to higher temperature ina tropical legume-plant pigeon pea (Cajanus cajari) have beenstudied using polyacrylamide gel electrophoresis. Ten to twelveheat shock proteins (hsps) of molecular weights ranging from15 to 81 kDa are synthesized by excised roots when temperatureis raised by 10?C above their normal growth temperature (30?C).The heat shock response is rapid and the presence of hsps canbe detected just 30 min after raising the temperature. Hspscan not be seen in stained gels, and their presence can onlybe monitored by fluorography. The results indicate the transientnature of their synthesis. Most of the hsps are of nuclear origin,however, at least two of them, 18 and 60 kDa proteins appearto be synthesized in mitochondria. (Received September 2, 1987; Accepted February 3, 1988)     

微波辅助提取木豆根中染料木素工艺

以木豆根为原料,利用微波辅助提取技术进行提取,在单因素实验的基础上对提取条件进行了考察,根据BBD(Box-Behnken design)实验设计原理,采用3因素3水平的响应面分析法,以木豆根中主要异黄酮染料木素(genistein)为指标,对提取过程进行优化,得到最佳工艺参数为：提取温度为68℃,固液比为32∶1 mL·g^-1,乙醇浓度为78%,提取功率700 W,提取时间15 min。在最佳提取条件下染料木素的提取率可达到0.465±0.032 mg·g^-1。本研究对于微波提取技术的应用及木豆根的开发和利用都具有显著的意义。     

Relationship between Field Levels and Light and Darkness on the Development of Phytophthora Blight of Pigeon Pea (Cajanus cajan (L.) Millsp.)

The incidence of Phytophthora blight of pigeon pea (Cajanus cajan (L.) Millsp.) caused by Phytophthora drechsleri f. sp. cajani was observed in the whole area of an experimental field plot where the topography varied. There was a positive correlation between low level of the field and maximum disease incidence. The incidence of disease was lowest at high field levels. This may be due to high or low moisture contents in both the levels. Leaf blight developed more rapidly under conditions of night darkness in the field and this was confirmed under conditions of artificial darkness in the glasshouse.     

Limiting an Insect Infestation of Nitrogen-Fixing Root Nodules of the Pigeon Pea (Cajanus cajan) by Engineering the Expression of an Entomocidal Gene in Its Root Nodules

A region of DNA which determined the production of the insecticidal toxin of Bacillus thuringiensis subsp. israelensis was cloned into a derivative of a broad-host-range group IncQ plasmid vector of gram-negative bacteria. The plasmid which we constructed was transferred by conjugative mobilization into a Bradyrhizobium species that nodulates pigeon peas. In this species the construction was maintained stably in the absence of selection and expressed the gene that was installed. Experiments in a greenhouse with the strain which we constructed indicated that this organism provides protection against root nodule damage by the larvae of the insect Rivellia angulata (Diptera).     

Haploid embryogenesis in anther cultures of pigeon-pea (Cajanus cajan)

Summary Pollen embryogenesis and callus showing a wide range of ploidy is induced in the in vitro cultured anthers of pigeon-pea. A suspension of pollen from such anthers incubated in drop cultures on agar medium develops further to form embryoids and colonies of callus.     

Biochemical changes in developing seeds of pigeonpea (Cajanus cajan)

Soluble sugars, starch, soluble nitrogen and protein nitrogen were studied in developing seeds of 3 cultivars of pigeonpea. When expressed on a per seed basis soluble sugars increased up to 35 days after flowering and then declined slightly. Rapid starch accumulation was observed between 14 and 28 days after flowering. The levels of soluble nitrogen and protein nitrogen underwent rapid changes during the same period. Amino-acid composition of seed protein was also studied at different stages of maturation. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of salt-soluble proteins revealed that seed storage globulins are formed after 14 days of flowering and do not change much during later stages of maturation.     

Carbohydrate Metabolism in Drought-Stressed Leaves of Pigeonpea (Cajanus cajan)

Pigeonpea is a tropical grain-legume, which is highly dehydrationtolerant. The effect of drought stress on the carbohydrate metabolismin mature pigeonpea leaves was investigated by withholding waterfrom plants grown in very large pots (50 kg of soil). The moststriking feature of drought-stressed plants was the pronouncedaccumulation of D-pinitol (1D-3-methyl-chiro-inositol), whichincreased from 14 to 85 mg g^–1 dry weight during a 27d stress period. Concomitantly, the levels of starch, sucroseand the pinitol precursors myo-inositol and ononitol all decreasedrapidly to zero or near-zero in response to drought. The levelsof glucose and fructose increased moderately. Drought stressinduced a pronounced increase of the activities of enzymes hydrolysingsoluble starch (amylases) and sucrose (invertase and sucrosesynthase). The two anabolic enzymes sucrose phosphate synthase(sucrose synthetic pathway) and myo-inositol methyl transferase(pinitol synthetic pathway) also showed an increase of activityduring stress. These results indicate that pinitol accumulatedin pigeonpea leaves, because the carbon flux was diverted fromstarch and sucrose into polyols. Key words: Drought, polyols, pinitol, sucrose, starch, pigeonpea     

Hypoglycemic activity of Cajanus cajan (seeds) in mice.

The effect of roasted and unroasted seeds of C. cajan on serum glucose levels of normal and alloxan diabetic mice were studied. Single doses of unroasted seeds (60% and 80%) on administration to normal as well as alloxanized mice showed significant reduction in the serum glucose levels after 1-2 hr and a significant rise at 3 hr. In case of roasted seeds, on other hand there was a significant increase in serum glucose levels during 3 hr experimental period. It is therefore concluded that roasting of seeds at high temperature for an half hour period resulted in the total loss of hypoglycemic principle but not the hyperglycemic principle present in the seeds.     

Somatic embryogenesis in cell suspension cultures of pigeonpea (Cajanus cajan)

Suspension cultures of calli derived from seedling leaf explants of Cajanus cajan L. var. Vamban-1 produced somatic embryos. The highest embryogenic frequency was induced on semisolid MS (Murashige and Skoog, 1962) medium supplemented with 6.78 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The maximum frequency of somatic embryogenesis was observed when this callus was transferred to MS liquid medium supplemented with 4.52 μM 2,4-D. Further studies on ontogeny of somatic embryos showed that the cells destined to become somatic embryos divided into spherical proembryos. Subsequent divisions in the proembryo led to globular, heart and torpedo-shaped somatic embryos. The germination of somatic embryos occurred on auxin-free MS basal medium. Effects of various auxins, cytokinins and carbohydrates on induction and frequency of somatic embryogenesis were studied. A medium supplemented with 4.52 μM of 2,4-D and 87.64 mM sucrose was effective in inducing a higher frequency of somatic embryos, whereas cytokinin had no effect and led to recallusing of embryos. About 5–6% of embryos converted into plants. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth of Foliage of Pigeon pea (Cajanus cajan [L.] Millsp.) and Disease Progress of Alternaria Blight

Vanderplank developed a model based on the logistic growth system to calculate the apparent infection rate (r) and to estimate plant disease progress. By estimating his r and p^∧ (infection rate corrected for growth) the results were frequently negative. Kushalappa and Ludwig later developed another model for adequately correcting the host growth. The present model is a modification of Kushalappa and Ludwig's model in which the results are positive in case of Alternaria blight of pigeon pea (Cajanus cajan [L.] Millsp.). The disease intensity increased despite host growth resulting into an epidemic. A factor accounting for leaf fall due to blighting has been taken into consideration.     

Characterization of NADP-Isocitrate Dehydrogenase from Nodules of Pigeonpea (Cajanus cajan)

NADP-isocitrate dehydrogenase from nodules of pigeonpea (Cajanus cajan L. cv UPAS-120) was partially purified to about 57 folds and its properties were studied. The enzyme showed an absolute requirement for a divalent cation which was fulfilled either by Mn⁺² or Mg⁺² and to a smaller extent by Co⁺². The enzyme exhibited a sigmoidal response to increasing concentrations of Mn²⁺ (S_0.5=0.3mM). The apparent Km values for isocitrate, NADP and Mg²⁺ were 21, 23 and 280 μM, respectively. It had an optimum pH of 8.0–8.2. The enzyme activity was not affected by various organic acids, amino acids and amides. NADH inhibited the activity non-competitively with respect to NADP. An apparent inhibition by ATP and ADP was due to chelation of divalent cation. NADPH acted competitively against NADP and non-competitively against isocitrate. Glutamate caused uncompetitive inhibition with respect to NADP and competitive against isocitrate. Kinetic studies suggested the reaction mechanism to be probably random sequential. Possible regulation of the enzyme activity in the nodules via cellular redox state and the levels of reaction products is discussed.     

Protease inhibitors of pigeonpea (Cajanus cajan) and its wild relatives

Plant protease inhibitors have been implicated in defense against insect pests. Podborer and pod fly are major pests of developing seeds of pigeonpea ( Cajanus cajan L. Millsp.). Therefore, we studied the presence of protease inhibitors in seeds of pigeonpea and its wild relatives. Seed extracts were analyzed for protease inhibitor activities by caseinolytic assay, and the number of protease inhibitors determined by polyacrylamide gel electrophoresis. Besides trypsin and chymotrypsin inhibitors, seed extracts contained weak papain inhibitor(s) but no bromelain inhibitor. Treatment of seed extract with bromelain generated new active forms of trypsin inhibitors. The relative amounts of different trypsin inhibitors and the total trypsin inhibitor activity varied with different extraction media. Trypsin inhibitors were not detectable in pigeonpea leaves. The profiles of trypsin and chymotrypsin inhibitors in almost all the cultivars of pigeonpea analyzed were similar; however, those in wild relatives were quite variable.     

Sex allocation and mating systems in pigeonpea,Cajanus cajan (Fabaceae)

Sex allocation theory predicts that: (1) resources allocated to androecium should decrease with an increase in selfing, (2) a decrease in androecium biomass should be accompanied by an increase in the biomass of pistils, and (3) a decrease in androecium biomass should be coupled with a decrease in flower size, specifically corolla biomass. Another predicted change in reproductive traits associated with variation in selfing concerns seed to ovule ratios, but does not directly stem from sex allocation theory. It has been postulated that seed to ovule ratios should be positively correlated with the amount of selfing. These predictions were tested for six accessions of pigeonpea,Cajanus cajan L., that differed in selfing rates. The results were remarkably in accordance with the predictions. We conclude that sex allocation theory provides a powerful tool to understand the evolution of many reproductive traits in plants.     

Variability in nuclear DNA content within pigeonpea,Cajanus cajan (Fabaceae)

4C DNA values have been estimated in 16 cultivars ofCajanus cajan by cytophotometry. The values range between 6.19 pg to 7.97 pg, a 23.6% variation. The cultivars form four groups which differ significantly from each other but have insignificant difference within them. The implications of this variability with respect to the heterogeneity and origin of this legume crop are discussed.     

Thidiazuron-induced shoot regeneration in pigeonpea (Cajanus cajan L.)

Thidiazuron either alone or in combination with IAA induced high frequency shoot regeneration from primary leaf segments of three pigeonpea cultivars. Transfer of the cultures to medium with reduced concentration of thidiazuron resulted in further development of the shoots. The regenerated shoots were subsequently transferred to medium supplemented with BA, IAA and gibberellic acid where 5-10% of the shoots elongated further. Rooting of shoots could be obtained on half strength MS medium supplemented with NAA. Histological studies confirmed the mode of regeneration as shoot organogenesis. This revised version was published online in June 2006 with corrections to the Cover Date.     

叶绿体小分子量热激蛋白介绍

本文对叶绿体小分子量热激蛋白的研究进行了简要的回顾和总结.叶绿体小分子量热激蛋白是热激蛋白超家族的成员,具有3个特殊的保守区域;当植物遇到热胁迫时,叶绿体小分子量热激蛋白能够保护光合系统Ⅱ和类囊体膜;初步分析了叶绿体小分子量热激蛋白与植物的耐热性和耐冷性关系以及其分子伴侣功能.     

Germinating pigeonpea (Cajanus cajan) seeds secrete factor(s) having antiethylene-like effects

Germinating pigeonpea seeds were found to release factor(s), which dramatically altered the growth pattern of rice seedlings. This included an increased sensitivity of roots to gravity, an increase in seminal root length, and increased density of branch roots on the seminal root and suppression of root hair formation. Furthermore, the known characteristic responses of rice to ethylene (namely, coleoptile growth promotion and induction of senescence) were inhibited by the presence of these factor(s). This altered growth pattern of rice seedlings was similar to that brought about by the ethylene-antagonist, silver nitrate. Further, the change in growth pattern in rice was specifically reversed by ethrel. In addition, in wild-type Arabidopsis thaliana these factors suppressed formation of root hair, the development of which is known to be promoted by ethylene. In contrast, in a mutant A. thaliana which shows constitutive ethylene response ( ctr1-1 ), the factors failed to inhibit root hair formation. These observations indicated that germinating pigeonpea seeds secrete factor(s), which have antiethylene-like effects.