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PubMed2002

STAIRS: a new genetic resource for functional genomic studies of Arabidopsis.

Many biologically and economically important traits in plants and animals are quantitative/multifactorial, being controlled by several quantitative trait loci (QTL). QTL are difficult to locate accurately by conventional methods using molecular markers in segregating populations, particularly for traits of low heritability or for QTL with small effects. In order to resolve this, large (often unrealistically large) populations are required. In this paper we present an alternative approach using a specially developed resource of lines that facilitate QTL location first to a particular chromosome, then to successively smaller regions within a chromosome (< or = 0.5 cM) by means of simple comparisons among a few lines. This resource consists of "Stepped Aligned Inbred Recombinant Strains" (STAIRS) plus single whole Chromosome Substitution Strains (CSSs). We explain the analytical power of STAIRS and illustrate their construction and use with Arabidopsis thaliana, although the principles could be applied to many organisms. We were able to locate flowering QTL at the top of chromosome 3 known to contain several potential candidate genes.

Arabidopsis↗
PubMed1998

Improving tomato harvest index by controlling crop height and side shoot production.

Given the constraints on physical space, energy supply, and labor availability, crop production efficiency must be maximized if a sustainable supply of food is to be produced on lunar and planetary space stations. In the modules designed for plant growth, crop production efficiency or the harvest index (HI, fruit weight/total plant weight) must be calculated on a cubic volume basis because the physical space allocated for plant growth will be limited in three dimensions. In order to increase HI, tomato plant architecture could be modified to reduce the extent of internode elongation and side shoot production. To test this hypothesis, plants were treated with the growth retardant paclobutrazol (PAC) and topped after the second flower cluster. PAC reduced plant height at harvest by 29% and total vegetative shoot growth by 28%. Fruit yield was reduced by 12%, although the greater reduction in vegetative growth by PAC resulted in an increased HI from 0.53 to 0.58 when calculated on a gram fresh weight basis. Yield/m3 of growing space utilized increased 23% with PAC treatment. The leaf axils of tomato plants grown in a single truss system were treated with the chemical pruning agent Off-Shoot-O (OSO), a mixture of short chain fatty acid methyl esters. OSO significantly reduced the number of side shoots/plant, increased fruit yield by 12%, and increased the HI from 0.71 to 0.77 compared to hand-pruned plants. Untreated plants required three manual pruning operations during the production period; plants treated with OSO were pruned only once at the time of application for a significant savings in labor. The results of both experiments clearly demonstrate that HI of tomato can be increased by reducing internode elongation and preventing side shoot development.

Biomass↗
PubMed2006

Relationship between gene differential expression of leaves in full opening flower stages of hybrids & their parents and heterosis in pest-resistant cotton.

cDNAs of leaves of 24 pest-resistant cotton (authorization) crosses and their parents in full opening flower stages were amplified and different bands were displayed by DDRT-PCR, with 45 primer combinations. The mean percentage of bands duplicated was 70.1%, which implied that there was a high proportion of pseudopositive fragments in the amplified cDNA. These pseudopositive bands can be reduced using duplicate PCR. Correlation analysis between differential gene expression and hybrid performance and heterosis showed that M4 (bands detected in one parent and F1) was positively correlated with all yield traits, and significantly correlated with boll number; M2 (bands observed in one parent but not in F1 and another parent) was negatively correlated with heterosis of boll number; and M3 (bands observed only in F1) was positively correlated with heterosis of lint yield. These results showed that genes that had dominant and specific expression in top leaves of full opening flower stages were beneficial to yield formation and heterosis occurrence.

Chimera↗
PubMed2005

[Functional analysis of vernalization-related gene VER17 in flower development using antisense RNA strategy in winter wheat].

To understand the function of vernalization-related gene VER17 in winter wheat (Triticum aestivum L. cv. Jingdong No.1), an antisense RNA strategy was used. The antisense VER17 with a vector pBI121 was constructed and transformed into winter wheat by using the pollen-tube-pathway method. Fourteen independent transgenic plants transformed with antisense VER17 and five control transformants transformed with pBI121 blank vector were obtained and confirmed by GUS histochemical assay and PCR-Southern blot analysis. Phenotypes of T(0) and T(1) transgenic plants showed that the plants of the antisense VER17 transgenic lines degenerated top or basal spikelets and had delayed flowering time, which suggested that the VER17 gene functions in accelerating flowering and the development of the top or basal spikelets and the stamen which were impacted by vernalization treatment.

Blotting, Southern↗
PubMed2002

Thermal insulation and accumulation of heat in the downy inflorescences of Saussurea medusa (Asteraceae) at high elevation in Yunnan, China.

Himalayan snowball plants, which are considered to be an extreme form of downy plants, have very dense trichomes on well-developed bracts that surround the inflorescences. It has been postulated that the downy inflorescences of these plants might serve to keep the interior of inflorescences warmer than the outside and, thus, to protect reproductive cells from low temperatures in their Himalayan habitat. In the present study, we examined the downy inflorescences of Saussurea medusaMaxim. in native habitats in the high alpine zone of the Henduan Mountains in Yunnan, China, and we analyzed the temperature within inflorescences after absorbance of light energy. S. medusais pollinated by bumblebees and we found that its inflorescences accumulated heat not on the inside, but, rather, on the upper surfaces. The thick hollow stems and the overlapping bracts with obvious epinasty might serve not only to retain heat, but also as an insulator to protect the inside against overheating, with apparent local warming of flowers that are located at the tops of plants, which are cone-shaped. We made a model that mimicked the warming of inflorescences, providing support for the hypothesis that the downy bracts of S. medusahave two functions: thermal insulation to protect the inside of flowers and the accumulation of heat on the upper surfaces of the inflorescence. Such a system might be effective in attracting pollinators and also in protecting tissues from extreme variations in temperature.

Journal Article↗
PubMed2003

Distyly and pollen dimorphism in Damnacanthus (Rubiaceae).

We document distyly in Damnacanthus (Rubiaceae) and investigate pollen morphology in the genus. Within nine taxa in Japan (four species, four varieties and one form), five show distyly. Non-distylous taxa of Damnacanthus always have a long style and short stamens. We examined the pollen morphology of all taxa of Damnacanthus in Japan. The pollen grains of Damnacanthus are 3- to 5-orthocolporate or sometimes loxocolporate. Polymorphic pollen is sometimes observed even within a single flower. Pollen dimorphism is associated with distyly; pollen grains from short-styled (thrum) flowers are significantly larger than those from long-styled (pin) flowers, and the muri are smooth in pin flowers whereas the pollen grains of thrum flowers have minute granules on the top and/or on the sides. In non-distylous taxa, in which the style is longer than stamens, the muri are always provided with minute granules. Interestingly, the pollen grains with granules in the non-distylous taxa contrast with the pollen of the distylous taxa, because granulate pollen grains are found only in thrum flowers. Although Damnacanthus is a stenopalynous genus, the number of colpi is useful for delimiting taxa. Based on palynological characters, we conclude that Damnacanthus should be revised.

Pollen↗
PubMed1997

Comparison of flowering time genes in Brassica rapa, B. napus and Arabidopsis thaliana.

The major difference between annual and biennial cultivars of oilseed Brassica napus and B. rapa is conferred by genes controlling vernalization-responsive flowering time. These genes were compared between the species by aligning the map positions of flowering time quantitative trait loci (QTLs) detected in a segregating population of each species. The results suggest that two major QTLs identified in B. rapa correspond to two major QTLs identified in B. napus. Since B. rapa is one of the hypothesized diploid parents of the amphidiploid B. napus, the vernalization requirement of B. napus probably originated from B. rapa. Brassica genes also were compared to flowering time genes in Arabidopsis thaliana by mapping RFLP loci with the same probes in both B. napus and Arabidopsis. The region containing one pair of Brassica QTLs was collinear with the top of chromosome 5 in A. thaliana where flowering time genes FLC, FY and CO are located. The region containing the second pair of QTLs showed fractured collinearity with several regions of the Arabidopsis genome, including the top of chromosome 4 where FRI is located. Thus, these Brassica genes may correspond to two genes (FLC and FRI) that regulate flowering time in the latest flowering ecotypes of Arabidopsis.

Arabidopsis↗
PubMed2006

[The changes of three endogenous hormones during flower bud differentiation of Schisandga chinensis].

OBJECTIVE: To reveal the relation between endogenous hormones and the flower bud differentiation in Schisandga chinensis. METHOD: Top buds of extremely short branch and axillary buds of long branch in the same plant of S. chinensis were used as material and the contents of endogenous hormones were measured during different periods of the flower bud differentiation with HPLC. RESULT: The result showed that flower bud differentiation and the formation of female flower were inhibited by high concentration of GA3 and were promoted by high concentration of ABA or ZT. Low ratio of GA3/ABA has the same result. CONCLUSION: There was a correlation between endogenous hormones and the flower bud differentiation of S. chinensis.

Abscisic Acid↗
PubMed1997

Angioarchitectural structure of the fungiform papillae on rabbit tongue anterodorsal surface.

The relationships between the functional and morphological characteristics and the positional difference of the microvascular cast specimen (MVCS) of the fungiform papillae (FuP) on the antero-dorsal surface of the rabbit tongue were examined and compared using a scanning electron microscope (SEM). The sporadic FuPs scattered among the numerous small filiform papillae (SfP) were found to be distributed irregularly over the antero-dorsal surface. FuPs consisted of the ascending and descending capillary loops, forming margins of the central opening at the top of FuP. They resembled flower-like configurations (carnations), the petals of which ranged from eight to twelve, and they were larger in width and more complex in shape than SfPs with morphological differences. FuPs can be classified into three types: type I (consisting of eight petals), type II (ten petals), type III (twelve petals) according to the shape of FuP, and to the petal number of the flower-like aspect on the eight points of MVCS of FuPs observed by SEM. These results suggest that the petals of the ascending and descending capillary loops of FuP expanded the flower-like figure, increased in the surface areas and effectively play a role in receiving the sense of taste.

Animals↗
PubMed2002

[Dynamics of predatory natural enemy community in cotton fields].

The dynamics of predatory natural enemy community in cotton field along the Yangtze River in Anhu province was studied. The results showed that there were totally 19 species of predatory natural enemies, and the dominant species were Propylaea japonica, Erigonidium graminicola, Theridium octomaculatum, Misumenops tricuspidatus, Orius minutes and Geocoris ochropterus. The predatory natural enemies in the cotton fields were rather abundant in the whole growing period of cotton, except the rainy season. Among the dominant species, P. japonica, M. tricuspidatus, O. minutes and G. ochropterus were distributed mainly in the upper and middle parts of cotton plants, while E. graminicola and T. octomaculatum mainly in the middle and lower parts of cotton plants. The diversities of the community were relatively high in the early developmental period of cotton, and reached the top level in the bud and flowering period of cotton in the first 10 days of July, then declined successively hereafter. The principal factor affecting the diversity was species richness in the early developmental period of cotton (from shoot period to bud and flowering period), and species evenness in the late developmental period of cotton (from flowering and boll period to boll opening period). The characteristics of the community were relatively analogous before the second 10 days of August (from shoot period to flowering and boll period of cotton), but after this period, the characteristics changed obviously with the features of the dominant species getting more and more conspicuous.

Animals↗
PubMed2002

Characterization and effects of the replicated flowering time gene FLC in Brassica rapa.

Functional genetic redundancy is widespread in plants and could have an important impact on phenotypic diversity if the multiple gene copies act in an additive or dosage-dependent manner. We have cloned four Brassica rapa homologs (BrFLC) of the MADS-box flowering-time regulator FLC, located at the top of chromosome 5 of Arabidopsis thaliana. Relative rate tests revealed no evidence for differential rates of evolution and the ratios of nonsynonymous-to-synonymous substitutions suggest BrFLC loci are not under strong purifying selection. BrFLC1, BrFLC2, and BrFLC3 map to genomic regions that are collinear with the top of At5, consistent with a polyploid origin. BrFLC5 maps near a junction of two collinear regions to Arabidopsis, one of which includes an FLC-like gene (AGL31). However, all BrFLC sequences are more closely related to FLC than to AGL31. BrFLC1, BrFLC2, and BrFLC5 cosegregate with flowering-time loci evaluated in populations derived by backcrossing late-flowering alleles from a biennial parent into an annual parent. Two loci segregating in a single backcross population affected flowering in a completely additive manner. Thus, replicated BrFLC genes appear to have a similar function and interact in an additive manner to modulate flowering time.

Base Sequence↗
PubMed2006

Morphological and molecular phylogenetic context of the angiosperms: contrasting the 'top-down' and 'bottom-up' approaches used to infer the likely characteristics of the first flowers.

Recent attempts to address the long-debated 'origin' of the angiosperms depend on a phylogenetic framework derived from a matrix of taxa versus characters; most assume that empirical rigour is proportional to the size of the matrix. Sequence-based genotypic approaches increase the number of characters (nucleotides and indels) in the matrix but are confined to the highly restricted spectrum of extant species, whereas morphology-based approaches increase the number of phylogenetically informative taxa (including fossils) at the expense of accessing only a restricted spectrum of phenotypic characters. The two approaches are currently delivering strongly contrasting hypotheses of relationship. Most molecular studies indicate that all extant gymnosperms form a natural group, suggesting surprisingly early divergence of the lineage that led to angiosperms, whereas morphology-only phylogenies indicate that a succession of (mostly extinct) gymnosperms preceded a later angiosperm origin. Causes of this conflict include: (i) the vast phenotypic and genotypic lacuna, largely reflecting pre-Cenozoic extinctions, that separates early-divergent living angiosperms from their closest relatives among the living gymnosperms; (ii) profound uncertainty regarding which (a) extant and (b) extinct angiosperms are most closely related to gymnosperms; and (iii) profound uncertainty regarding which (a) extant and (b) extinct gymnosperms are most closely related to angiosperms, and thus best serve as 'outgroups' dictating the perceived evolutionary polarity of character transitions among the early-divergent angiosperms. These factors still permit a remarkable range of contrasting, yet credible, hypotheses regarding the order of acquisition of the many phenotypic characters, reproductive and vegetative, that distinguish 'classic' angiospermy from 'classic' gymnospermy. The flower remains ill-defined and its mode (or modes) of origin remains hotly disputed; some definitions and hypotheses of evolutionary relationships preclude a role for the flower in delimiting the angiosperms. We advocate maintenance of parallel, reciprocally illuminating programmes of morphological and molecular phylogeny reconstruction, respectively supported by homology testing through additional taxa (especially fossils) and evolutionary-developmental genetic studies that explore genes potentially responsible for major phenotypic transitions.

Botany↗
PubMed2000

Isolation and characterization of an Arabidopsis mutant, fireworks (fiw), which exhibits premature cessation of inflorescence growth and early leaf senescence.

To examine the mechanism underlying the reproductive development in monocarpic plants, we screened for mutants that exhibit premature cessation of inflorescence growth in Arabidopsis. We identified a novel mutant line that exhibited earlier cessation of flower formation and inflorescence stem elongation. This mutant also exhibited accelerated rosette leaf senescence after the cessation of the inflorescence growth. We designated the mutant fireworks (fiw) because flowers and siliques were clustered at the top of the fiw inflorescence. The fiw mutation was a single, recessive mutation and mapped on the lower part of chromosome 4. The fiw phenotype was not observable during vegetative growth, but the inflorescence growth was arrested more than 7 d earlier than the wild type (WT). Microscopic observation revealed that the fiw apical meristem was structurally preserved. The premature arrest of growth was observed not only in the primary inflorescence but also in the lateral inflorescence, which is consistent with the global proliferative arrest observed later in WT. Regardless of such dramatic phenotypic features, the fiw plants bore normal flowers and set fully matured siliques.

Arabidopsis↗
PubMed2006

Sheath-assisted controlled deployment technique for Excluder bifurcated main body.

The W. L. Gore Excluder bifurcated device uses a single-action deployment mechanism with an expanded polytetrafluoroethylene string that is stitched to an outer jacket constraining the nitinol self-expanding stent-graft. Under certain anatomic conditions of the proximal neck, the deployment angle of the proximal stent-graft can be difficult to predict and result in the device being seated caudal to the intended landing site just below the lowermost renal artery. This article describes a technique of controlled deployment of the Excluder device where the top of the main bifurcated device is "flowered" by slowly pulling the deployment string while being buttressed by an introducer sheath to prevent premature deployment and allow longitudinal positioning of the device. This technique could be used when a more gradual deployment of the Excluder device is desired in angulated or short proximal necks.

Angioplasty↗
PubMed1992

Differential expression of two MADS box genes in wild-type and mutant petunia flowers.

We isolated and characterized two flower-specific genes from petunia. The protein products of these genes, designated floral binding protein 1 (FBP1) and 2 (FBP2), are putative transcription factors with the MADS box DNA binding domain. RNA gel blot analysis showed that the fbp1 gene is exclusively expressed in petals and stamen of petunia flowers. In contrast, the FBP1 protein was only detectable in petals and not in stamens, suggesting post-transcriptional regulation of the fbp1 gene in these tissues. The fbp2 gene is expressed in petals, stamen, carpels, and at a very low level in sepals but not in vegetative tissues. We analyzed the spatial expression of these fbp genes in floral organs of two homeotic flower mutants. In the blind mutant, whose flower limbs are transformed into antheroid structures on top of normal tubes, identical expression levels of both genes were observed in the antheroid structures as in normal anthers. In the homeotic mutant green petals, the petals are replaced by sepaloid organs in which the expression of fbp1 is strongly reduced but not completely abolished. Our results suggest a regulation of the fbp1 gene expression by the green petals (gp) gene. Expression of the fbp2 gene was not affected in the green petals mutant. In contrast to the proposed models describing floral morphogenesis, our data indicated that homeotic genes can be functional in one whorl only.

Amino Acid Sequence↗
PubMedDate not supplied

[Formation of flavonoid pigments during flower color development in sweet pea Lathyrus odoratus L. mutants].

We studied the variability of two classes of flavonoid pigments (flavonols and anthocyanidins) in seven sweet pea mutant lines. Flavonols proved to be synthesized before anthocyanidins during the color formation of the petals. The top content of flavonols was observed at the third stage of flower development, while the anthocyanidins content peaked at the fifth stage. The pigments with the more hydroxylated B ring were synthesized at later stages of the flower development as well. The stages of flavonols and anthocyanidins biosynthesis controlled by the corresponding genes, as well as the possible genetic mechanism of a fast and complete transformation of the precursors to the final products of the biosynthetic chain, are considered.

Anthocyanins↗
PubMed2002

Bumblebee-pollination and temporal change of the calyx tube length in Clematis stans(Ranunculaceae).

Clematis stans is dioecious semi-arboreal, with pale purple-blue, nodding, tubulous flowers in a paniculate inflorescence. Both male and female flowers produce nectar from the base of the calyx tube during a flowering period of 3 or 4 days, and are pollinated by two bumblebee species, Bombus diversus and B. honshuensis,with different proboscis lengths. When the flowers open, four sepals constructing a calyx tube separate at the top and their respective tips gradually curl up, so that a tubular part shortens. Observations at two field sites showed that B. diversus (with a longer proboscis) most often visits the flowers with a longer calyx tube, and B. honshuensis (with a shorter proboscis) the flowers with a shorter calyx tube, i.e., later in the flowering period. By changing the calyx tube length, the flowers of C. stans accept the two bumblebee species with different proboscis length as pollinators and thus increase the chance of pollination for each flower. It was also found that the two bumblebee species prefer the male flowers to the female flowers, although the female flowers secrete more nectar as a reward than male flowers. This is likely because they visit the male flowers to collect pollen grains in addition to nectar.

Journal Article↗
PubMed2000

[Distribution patterns of shoots, flowers and seeds in Ginkgo biloba canopy and their relationships].

The distribution patterns of shoots, flowers and seeds in the canopy of 14 years old engrafted Ginkgo biloba and their relationships were investigated with stratification method. The result shows that long shoots, short shoots, bearing-shoots and flowers uniformly distributed in the central section of canopy. From the top to the bottom, the average age and the divaricating angle of long shoots increase 51.3% of the seeds distributed in 180-320 cm layer from the ground. The number of shoots, flowers and seeds in different canopy layers was closely correlated.

Ginkgo biloba↗