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After examining a large number of type and authoritative specimens of Schizophragma Siebold & Zucc., S. elliptifolium C. F. Wei and S. integrifolium var. glaucescens Rehder were reduced to synonyms of S. hypoglaucum Rehder and S. integrifolium f. cordatum S. Y. Wang was reduced to synonym of S. corylifolium Chun. Schizophragma crassum var. ellipticum J. Anthony was treated as the correct name of S. crassum var. hsitaoanum (Chun) C. F. Wei. The name S. integrifolium var. minus Rehder is reinstated. The taxonomic treat-ment is supported by leaf epidermal characters. 相似文献
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Information on reproduction and life history is important for the conservation of endangered plants. We investigated rates of flowering, seed set, and germination in populations of the endangered perennial plant Sedum integrifolium ssp. leedyi. Germination and flowering rates differed significantly among populations, but seed set rate did not. We assayed 26 plant clusters (81 stems) from four of the five known populations for evidence of clonal reproduction using 28 randomly amplified polymorphic DNA (RAPD) markers. Of the 81 stems, 75 had unique genotypes and three pairs had identical genotypes, suggesting that clonal reproduction is infrequent. Flowering, seed set, and germination rates were correlated with our estimates of ratios of effective to actual population sizes (Ne/N), but not with Ne. The single formally protected population may be experiencing inbreeding depression. We grew plants from seed to maturity in a greenhouse, with a germination rate of 77% and survival of 98% of the germinants at 6 mo, suggesting that this will be a viable means of ex situ propagation. Plants flowered 4-6 mo after germination and produced mature fruits 1-2 mo later, suggesting that they have the potential to sexually reproduce in their first or second season of growth. 相似文献
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Solanum melongena (eggplant) cv. Picentia and the wild species Solanum integrifolium were transformed with both a wild type (wt) and four mutagenized versions of Bacillus thuringiensis (Bt) gene Bt43 belonging to the cry3 class. The Bt gene was partly modified in its nucleotide sequence by replacing four target regions (W: +1 to +170; X: +592 to+1057 ; Y: +1203 to +1376; Z: +1376 to +1984) with synthetic fragments obtained by polymerase chain reaction amplification of crude oligonucleotides. The synthetic Bt genes were designed to avoid, in their modified regions, sequences such as ATTTA sequence, polyadenylation sequences and splicing sites, which might destabilize the messenger RNA. Furthermore, the codon usage was improved for a better expression in the plant system. The amino acid composition was not altered. Four versions of the modified Bt gene were obtained, BtE, BtF, BtH and BtI, with a nucleotide subtitution percentage of 8.2, 8.6, 14, and 16%, respectively, in comparison to the wt gene Bt43. Modified versions contained different subsets of substituted regions: BtE - W+Z, BtF - Y+Z, BtH - X+Y+Z, BtI - W+X+Y+Z. In the final modified version (BtI), overall guanine + cytosine was increased from the 34.1% of the wt gene to 45.5%, and most of the destabilizing sequences were eliminated. Transgenic plants obtained with the more modified versions, BtH and BtI, were fully resistant to Leptinotarsa decemlineata Say first- and third- instar larvae, while Bt43 wt, BtE and BtF genotypes did not cause mortality and did not affect larval development. 相似文献
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After examining a large number of type and authoritative specimens of Schizophragma Siebold & Zucc., S. elliptifolium C. F. Wei and S. integrifolium var. glaucescens Rehder were reduced to synonyms of S. hypoglaucum Rehder and S. integrifolium f. cordatum S. Y. Wang was reduced to synonym of S. corylifolium Chun. Schizophragma crassum var. ellipticum J. Anthony was treated as the correct name of S. crassum var. hsitaoanum (Chun) C. F. Wei. The name S. integrifolium var. minus Rehder is reinstated. The taxonomic treatment is supported by leaf epidermal characters. 相似文献
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