The breeding system of an endangered dioecious species, Woonyoungia septentrionalis (Dandy) Law, was studied in two natural populations, the Mulun population and the Dahuangni population, in Guangxi Province, China fr...The breeding system of an endangered dioecious species, Woonyoungia septentrionalis (Dandy) Law, was studied in two natural populations, the Mulun population and the Dahuangni population, in Guangxi Province, China from June 2001 to early September 2002. The female flowers from previously bagged buds were treated respectively with paper bags, net bags and hand pollination by comparing with natural pollination. The results showed that female flowers treated with paper bags, net bags, hand pollination, and natural pollination all set fruits and seeds, but there was great difference in their fruit set, seed set, pre-emergent reproductive success (PERS) and seed germination rate for two populations. In both populations, PERS of hand pollination and natural pollination were higher than those of paper bagged and net bagged treatments. Among them, PERS of hand pollination was the highest, and PERS of net bagged treatment was the lowest. Both sexual reproduction and apomixis occurred simultaneously in W septentrionalis and seeds from both sexual and apomixis could germinate into seedlings. Therefore, the breeding system of W septentrionalis belonged to facultative apomixis. The apomixis in Magnoliaceae was reported for the first time.展开更多
Woonyoungia septentrionalis （Dandy） Law is aceae. The floral morphology and structure of the species a dioecious species with unisexual flowers in Magnoliare conspicuously different from other species and are import...Woonyoungia septentrionalis （Dandy） Law is aceae. The floral morphology and structure of the species a dioecious species with unisexual flowers in Magnoliare conspicuously different from other species and are important to the study of floral phylogeny in this family. The floral anatomy and ontogeny were investigated to evaluate the systematic position of W. septentrionalis, using scanning electron microscopy and light microscopy. All of the floral organs are initiated acropetally and spirally. The carpels are of conduplicated type without the differentiation of stigma and style. The degenerated stamens in the female flowers have the same structures as the normal stamens at the earlier developmental stages, but they do not undergo successive development and eventually degenerate. The male floral apex was observed to have the remnants of carpels in a few investigated samples. As the bisexual flower features could be traced both in the male and female flowers in W. septentrionalis, it suggests that the flower sex in Magnoliaceae tends toward unisexual. As well as the unisexual flowers, the reduced tepals and carpels and concrescence of carpels conform to the specialized tendency in Magnoliaceae, which confirms the derived position of W. septentrionalis in this family. As the initiation pattern of floral parts of W. septentrionalis is very similar to other species in this family, it needs further investigation and especially comparison with species in Kmeria to evaluate the separation of Woonyoungia.展开更多
This study represents a continuation of the Florida hotspot of tadpole abnormality found in the Southwest Florida suburban roadside drainage ditches in 2012 to determine if the adult frogs and toads frequenting the st...This study represents a continuation of the Florida hotspot of tadpole abnormality found in the Southwest Florida suburban roadside drainage ditches in 2012 to determine if the adult frogs and toads frequenting the study sites were anatomically abnormal.The gross examination of all organs included 397 adult anurans and 40 metamorphs representing five anuran species:Osteopilus septentrionalis(N=364),Rhinella marina(N=60),Lithobates sphenocephala(N=7),Anaxyrus terrestris(N=5)and Anaxyrus americanus(N=1).The gonads,liver,kidney and intestines were abnormal at a frequency of 87.4%.The few normal anurans(12.6%)were females and young male adults.We found a significant difference in organ abnormality type and f requency between sexes.Almost all f rog and toad males had testicular abnormality(92%)with only 6%with normal testes,whereas the female gonad abnormality was lower,at 41.6%.Hermaphroditism was found in both sexes at a frequency of 26.2%.The toads had a significantly higher frequency of hermaphroditism than the frogs.The toad hermaphroditism frequency was found to be 40%,whereas the frog hermaphroditism 23.3%.A hermaphrodite Cane toad male with a female phenotype coexisted with the normal male phenotype hermaphrodite.The fertility of 27 in situ pairs was assessed.The fertile testicular abnormal male and hermaphrodite pairs produced offspring with abnormal larval morphology.This information adds new evidence of the effect of chemicals on wild populations and the effect on non-target species which has always been underestimated.展开更多
We used Takydromus septentrionalis,a sexually size-monomorphic lacertid lizard,as a model system to test the hypothesis that sexual size monomorphism may evolve in lizards where reproductive performance is maximized a...We used Takydromus septentrionalis,a sexually size-monomorphic lacertid lizard,as a model system to test the hypothesis that sexual size monomorphism may evolve in lizards where reproductive performance is maximized at a similar body size for both sexes.We allowed lizards housed in laboratory enclosures to lay as many clutches(for females)as they could or to mate as many times(for males)as they could in a breeding season.Size-assortative mating was weak but evident in T.septentrionalis,as revealed by the fact that male and female snout–vent lengths(SVLs)in mating pairs were significantly and positively correlated.Mating frequency(indicative of male reproductive performance)varied from 1 to 8 per breeding season,generally increasing as SVL increased in adult males smaller than 67.4 mm SVL.Clutch frequency varied from 1 to 7 per breeding season,with female reproductive performance(determined by clutch frequency,annual fecundity,and annual reproductive output)maximized in females with a SVL of 68.0 mm.Accordingly to our hypothesis,the reproductive performance was maximized in the intermediate sized rather than the largest individuals in both sexes,and the body size maximizing reproductive performance was similar for both sexes.Future work could usefully investigate other lineages of lizards with sexually monomorphic species in a phylogenetic context to corroborate the hypothesis of this study.展开更多
文摘The breeding system of an endangered dioecious species, Woonyoungia septentrionalis (Dandy) Law, was studied in two natural populations, the Mulun population and the Dahuangni population, in Guangxi Province, China from June 2001 to early September 2002. The female flowers from previously bagged buds were treated respectively with paper bags, net bags and hand pollination by comparing with natural pollination. The results showed that female flowers treated with paper bags, net bags, hand pollination, and natural pollination all set fruits and seeds, but there was great difference in their fruit set, seed set, pre-emergent reproductive success (PERS) and seed germination rate for two populations. In both populations, PERS of hand pollination and natural pollination were higher than those of paper bagged and net bagged treatments. Among them, PERS of hand pollination was the highest, and PERS of net bagged treatment was the lowest. Both sexual reproduction and apomixis occurred simultaneously in W septentrionalis and seeds from both sexual and apomixis could germinate into seedlings. Therefore, the breeding system of W septentrionalis belonged to facultative apomixis. The apomixis in Magnoliaceae was reported for the first time.
基金supported by the National Natural Science Foundation of China(30770140,30470186,30370108)the Guangdong Provincial Natural Science Foundation(5006764)+1 种基金the Botanical Garden and Taxonomy Project of the Knowledge Innovation Engineering of the Chinese Academy of Sciences(KSCX2-YW-Z-026)the Science and Technology Project of Guangdong Province(2007A020200004-8)
文摘Woonyoungia septentrionalis （Dandy） Law is aceae. The floral morphology and structure of the species a dioecious species with unisexual flowers in Magnoliare conspicuously different from other species and are important to the study of floral phylogeny in this family. The floral anatomy and ontogeny were investigated to evaluate the systematic position of W. septentrionalis, using scanning electron microscopy and light microscopy. All of the floral organs are initiated acropetally and spirally. The carpels are of conduplicated type without the differentiation of stigma and style. The degenerated stamens in the female flowers have the same structures as the normal stamens at the earlier developmental stages, but they do not undergo successive development and eventually degenerate. The male floral apex was observed to have the remnants of carpels in a few investigated samples. As the bisexual flower features could be traced both in the male and female flowers in W. septentrionalis, it suggests that the flower sex in Magnoliaceae tends toward unisexual. As well as the unisexual flowers, the reduced tepals and carpels and concrescence of carpels conform to the specialized tendency in Magnoliaceae, which confirms the derived position of W. septentrionalis in this family. As the initiation pattern of floral parts of W. septentrionalis is very similar to other species in this family, it needs further investigation and especially comparison with species in Kmeria to evaluate the separation of Woonyoungia.
文摘This study represents a continuation of the Florida hotspot of tadpole abnormality found in the Southwest Florida suburban roadside drainage ditches in 2012 to determine if the adult frogs and toads frequenting the study sites were anatomically abnormal.The gross examination of all organs included 397 adult anurans and 40 metamorphs representing five anuran species:Osteopilus septentrionalis(N=364),Rhinella marina(N=60),Lithobates sphenocephala(N=7),Anaxyrus terrestris(N=5)and Anaxyrus americanus(N=1).The gonads,liver,kidney and intestines were abnormal at a frequency of 87.4%.The few normal anurans(12.6%)were females and young male adults.We found a significant difference in organ abnormality type and f requency between sexes.Almost all f rog and toad males had testicular abnormality(92%)with only 6%with normal testes,whereas the female gonad abnormality was lower,at 41.6%.Hermaphroditism was found in both sexes at a frequency of 26.2%.The toads had a significantly higher frequency of hermaphroditism than the frogs.The toad hermaphroditism frequency was found to be 40%,whereas the frog hermaphroditism 23.3%.A hermaphrodite Cane toad male with a female phenotype coexisted with the normal male phenotype hermaphrodite.The fertility of 27 in situ pairs was assessed.The fertile testicular abnormal male and hermaphrodite pairs produced offspring with abnormal larval morphology.This information adds new evidence of the effect of chemicals on wild populations and the effect on non-target species which has always been underestimated.
基金This work was carried out in compliance with the current laws of China and was supported by grants from the National Natural Science Foundation of China(32071511,31301878,and 31300339)。
文摘We used Takydromus septentrionalis,a sexually size-monomorphic lacertid lizard,as a model system to test the hypothesis that sexual size monomorphism may evolve in lizards where reproductive performance is maximized at a similar body size for both sexes.We allowed lizards housed in laboratory enclosures to lay as many clutches(for females)as they could or to mate as many times(for males)as they could in a breeding season.Size-assortative mating was weak but evident in T.septentrionalis,as revealed by the fact that male and female snout–vent lengths(SVLs)in mating pairs were significantly and positively correlated.Mating frequency(indicative of male reproductive performance)varied from 1 to 8 per breeding season,generally increasing as SVL increased in adult males smaller than 67.4 mm SVL.Clutch frequency varied from 1 to 7 per breeding season,with female reproductive performance(determined by clutch frequency,annual fecundity,and annual reproductive output)maximized in females with a SVL of 68.0 mm.Accordingly to our hypothesis,the reproductive performance was maximized in the intermediate sized rather than the largest individuals in both sexes,and the body size maximizing reproductive performance was similar for both sexes.Future work could usefully investigate other lineages of lizards with sexually monomorphic species in a phylogenetic context to corroborate the hypothesis of this study.
