Seed germination of herbaceous and woody species of the Sudanian savanna-woodland in response to heat shock and smoke

Fire-related cues (smoke and heat) contribute largely to changes in vegetation communities in fire prone habitats. The germination responses of seeds of species from Combretaceae, Leguminosae and Poaceae to smoke, heat or their interaction were examined. Half of the seed batch was first exposed to cold aerosol smoke for 60 min. Untreated and smoked seed batches were then subjected to heat treatment by incubating them at 40 °C, 80 °C or 120 °C for 2.5 min. The results showed that the seed germination of fire-adapted species, Terminalia avicennioides (p < 0.01) and Pteleopsis suberosa (p < 0.05), was stimulated by smoke, while the germination of fire-sensitive species, Anogeissus leiocarpus (p < 0.001) and Andropogon gayanus (p < 0.05) was inhibited by heat and smoke, respectively. Seeds of fire-tolerant species (Combretum glutinosum and Combretum nigricans) germinated favorably in response to heat and smoke treatments. The germination response of leguminous species was not significant with respect to the smoke and heat levels applied. In conclusion, there was no persistent pattern across all species that can easily explain their responses to fire-related cues, which can be related to species-specific requirements for a given dosage–response level, which in turn is attributed to the levels of heat shock and smoke treatments adopted in the present study. Testing different exposure times to heat shock and varying doses of smoke on large number of species is needed before generalization about community level response to fire could be drawn.     

豆科蔬菜花粉形态的研究

应用扫描电子显微镜对豆科蔬菜花粉形态进行了观察,结果表明,豆科蔬菜花粉类型较多,形状有长球形,近球形和球形,萌发孔有３孔沟,３拟孔沟和３孔等类型,外壁纹饰以网状雕纹花粉较多,对花粉的大小,Ｐ／Ｅ比等数量性状进行了聚灰分析,分析比较结果为研究其系统演化和分类提供了依据。     

内蒙古豆科新分类群

本文根据《国际植物命名法规》对内蒙古地区豆科5新种、2新变种、1变型进行了命名和描述。     

18种豆科树种染色体数目与结瘤关系的研究

对18种豆科树种的染色体计数结果表明,豆科树种的染色体数目与其结瘤之间存在一定的关系.不结瘤的10种树种除望江南染色体数是26条外,其余9种树种的染色体数目都为2n=2x=28,都能被7整除,其中包括苏木亚科的槐叶决明、伞房决明、双荚决明、毛决明、黄槐决明、铁刀木、任豆、皂荚和蝶形花亚科中的国槐;而结瘤的8种树种,其中含羞草亚科的合欢、银荆、肯氏相思、马占相思,它们的染色体数目均为2n=2x=26;蝶形花亚科的马蹄针为2n=2x=18,紫穗槐为2n=2x=40,刺槐、木豆均为2n=2x=22,它们的染色体数目都不是7的倍数.     

Genetic variability and association studies in pod and seed traits of <Emphasis Type="Italic">Pongamia pinnata</Emphasis> (L.) Pierre in Haryana,India

Forty Candidate Plus Trees (CPTs) of Pongamia pinnata were selected based on the morphometric traits to identify suitable seed sources with high oil content and for production of quality seedlings for mass afforestation in different forestry and agroforestry programmes. Significant genetic variability and association were recorded among 40 CPTs for pod and seed traits. Maximum 100-seed weight (186.80 g) and pod-weight (403.94 g) was recorded in CPT-33, while CPT-18 showed maximum oil content (44.07%). In general, phenotypic coefficient of variation was higher than genotypic coefficient of variation indicating the predominant role of environment. High heritability (broad sense) and genetic gain observed for pod–seed ratio (99.00%, 87.78%), 100-seed weight (100.00%, 66.99%) and 100-pod weight (98.00%, 57.38%), respectively indicate additive gene action. Seed weight and pod weight showed positive and significant correlation with oil content. CPTs 18, 20, 33, 13 and 29 were found to be the best on the basis of oil content and pod–seed characters.     

Lectin Gene Sequences and Species Relationships among Cultivated Legumes

Lectins are a class of defence proteins of non-immune origin that bind carbohydrate in a reversible fashion. In some cultivated legume species, lectin protein coding genes were PCR amplified using primers designed on the basis of conserved N- and C-terminal amino acid sequences of the common bean (one-chain) or pea (two-chains) lectins. Amplification products of the expected length were obtained in Lathyrus sativus L., Vicia faba L. var. faba, Phaseolus coccineus L., and Vigna unguiculata (L.) Walp. No amplification product or agglutinating activity against blood cells, and/or cross-reaction with specific antibodies were detected in Lupinus albus L. and Cicer arietinum L. Finally, the new isolated nucleotide sequences, together with other legume lectin sequences already present in the EMBL Database, were used for evolutionary analysis. This last indicated the existence of two main clusters; one grouping all the species belonging to the Phaseoleae tribe and the other one grouping Lens culinaris Medik., Pisum sativum L., L. sativus, and V. faba, members of the Vicieae tribe. Results were congruent with the taxonomic classification and suggested that the lectin genes divergence in legume followed species evolution.     

Genetic variation analysis in the genus Lathyrus using RAPD markers

RAPD analysis was applied to five species belonging to the genusLathyrus (Fabaceae): L.sativus, L.cicera, L.ochrus, L.sylvestris and L.latifolius. All the species under study belong to thesection Lathyrus except L.ochrus which is in section Clymenum.Nine populations representing these species were used and ten random10-mer primers were sampled. A total of 129 amplification products,ranging in size from 0.3 to 3 Kb, were generated. Partitioning ofvariation was studied using the AMOVA technique. The genetic variation proved tobe nearly equally distributed among species and among populations withinspecies. A similar approach was carried out to distinguish populations, whichproved to be efficient. The between population dissimilarities were calculatedand a dendrogram of genetic relationships was drawn. The RAPDs obtained weresufficient to distinguish between the two accessions of a species and toseparate these accessions by clustering them according to species. A highgenetic similarity between the populations of L.sylvestris and L.latifolius was established. A similar result is also shownfor the populations of L. sativus andL. cicera.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Three new acetylated benzyl-beta-resorcylate glycosides from Cassia obtusifolia

Three new acetylated benzyl-beta-resorcylate glycosides (1-3) were isolated from seeds of Cassia obtusifolia. Their structures were determined on the basis of the spectroscopic methods and physicochemical properties as 2-benzyl-4,6-dihydroxy benzoic acid-6-O-[2,6-O-diacetyl]-d-glucopyranoside (1), 2-benzyl-4,6-dihydroxy benzoic acid-6-O-[3,6-O-diacetyl]-d-glucopyranoside (2) and 2-benzyl-4, 6-dihydroxy benzoic acid-6-O-[4,6-O-diacetyl]-d-glucopyranoside (3), respectively.     

Effect of rotenoids from the seeds of Millettia dura on larvae of Aedes aegypti

A crude chloroform extract of seeds of Millettia dura Dunn (Leguminosae) showed high activity (LC50 = 3.5 microg ml(-1) at 24 h) against second-instar larvae of the mosquito, Aedes aegypti L (Diptera: Culicidae). The rotenoids, deguelin and tephrosin, isolated from the seeds of this plant also showed potent activities, with LC50 values of 1.6 and 1.4 microg ml(-1) at 24 h, respectively. The related rotenoids millettone and millettosin were inactive at 20 microg ml(-1). Saturation at the B/C ring junction and the presence of methoxy groups at C-2 and/or C-3 in deguelin and tephrosin appear to be important for the observed larvicidal activity.