Stylonema alsidii(Zandardini)Drew f.ramosum Zheng et Li is a common species in the genus Stylonema,but there are limited reports on morphological taxonomy and a lack of studies on life history and the regulation of ea...Stylonema alsidii(Zandardini)Drew f.ramosum Zheng et Li is a common species in the genus Stylonema,but there are limited reports on morphological taxonomy and a lack of studies on life history and the regulation of early development.The early development,discoid formation,and erect thallus growth of Stylonema alsidii f.ramosum were observed under laboratory conditions.In addition,the influence of main environmental factors such as temperature and light intensity on its development was briefly studied,and various stages of its life history were observed.The result shows:(1)there are two reproductive modes:asexual reproduction and sexual reproduction;(2)the morphology of this species varies in different degrees under laboratory culture conditions;(3)sexual reproduction and asexual reproduction can coexist under suitable conditions.Five pathways of life history were inferred from experimental phenomena.Mature sporophytes form mature gametophytes by producing initially isolated or initially attached monospore,and mature gametophytes form mature sporophytes by fertilization of eggs and sperms.The sexual and asexual reproduction processes of Stylonema alsidii f.ramosum were reported for the first time,and this is also the first report on sexual reproduction in the genus Stylonema.展开更多
Exploratory surveys were carried out in the Andamans and Nicobar group of islands during 2006 and 2014 to locate wild species viz. Mangifera andamanica King, Mangifera camptosperma Pierre and Mangifera griffithii Hook...Exploratory surveys were carried out in the Andamans and Nicobar group of islands during 2006 and 2014 to locate wild species viz. Mangifera andamanica King, Mangifera camptosperma Pierre and Mangifera griffithii Hook. Not much variation was observed for fruit shape and size for the species Mangifera andamanica, which was endemic to this region. The species M. griffithii has been reported to be only in Mt. Harriet. However, another plant of M. griffithii in the Shoalbay region was found during the second survey. The foliage & fruit characteristics of the two specimens were similar, with a slight difference in the morphological features, which could be attributed to their origin from seeds. The DNA finger printing carried out showed minor changes in the species. The phylogenetic relationships amongst five Mangifera species viz. M. indica, M. griffithii, M. camptosperma, M. odorata and M. andamanica were analyzed by employing chloroplast markers viz., petB-petD intergenic spacer, rps16 gene, trnL-trnF intergenic spacer and nuclear marker—External Transcribed Spacer (ETS). The nuclear markers and chloroplast markers based on phylogenetic analysis showed that the common mango M. indica L. was closely related to M. griffithii and M. camptosperma, which belonged to subgenus Mangifera. However, M. odorata that belonged to subgenus Limus was grouped separately along with M. andamanica. The above results are in congruent with the accepted classification of genus Mangifera reported by Kostermans and Bompard with the exception of M. andamanica, which has been earlier classified under subgenus Mangifera. Results clearly indicated that classification of M. andamanica under subgenus needed to be reconsidered.展开更多
为探讨火烧干扰以及微地貌差异对高原湿草甸植被的影响,以高原湿草甸优势种华扁穗草(Blysmus sinocompressus Tang et F.T.Wang)为研究对象,分别在经历火烧干扰和未烧的湿地中选择平地和地垄作为样地,研究了不同生长期以及不同年份华扁...为探讨火烧干扰以及微地貌差异对高原湿草甸植被的影响,以高原湿草甸优势种华扁穗草(Blysmus sinocompressus Tang et F.T.Wang)为研究对象,分别在经历火烧干扰和未烧的湿地中选择平地和地垄作为样地,研究了不同生长期以及不同年份华扁穗草地上部的灰分含量和热值(包括干质量热值和去灰分热值)变化。结果表明:在火烧平地、火烧地垄、未烧平地和未烧地垄4类样地中,不同生长期以及不同年份间华扁穗草地上部的灰分含量和热值均有一定差异。在火烧平地、火烧地垄和未烧平地3类样地中,与生长初期相比,生长旺盛期华扁穗草地上部的灰分含量均降低,其干质量热值和去灰分热值均升高;而在未烧地垄样地中,与生长初期相比,生长旺盛期华扁穗草地上部的灰分含量显著升高,其干质量热值和去灰分热值则均略降低。从样地类型看,在生长旺盛期,平地样地中华扁穗草地上部的灰分含量均低于地垄样地,其干质量热值和去灰分热值均高于地垄样地,其中,其灰分含量在火烧平地样地中最低、在未烧地垄样地中最高;其干质量热值和去灰分热值在火烧地垄样地中均最低、在未烧平地样地中均最高,但总体无显著差异。随时间推移,火烧样地特别是火烧平地样地中华扁穗草地上部的灰分含量增加,而其干质量热值和去灰分热值则有所降低但总体上与未烧样地间无显著差异。总体上看,在火烧样地中,华扁穗草地上部的干质量热值和去灰分热值低于未烧样地;而在平地样地中,其干质量热值和去灰分热值高于地垄样地。研究结果显示:火烧干扰和微地貌差异对华扁穗草地上部的灰分含量和热值均有一定的影响,据此,建议将植物地上部的灰分含量和热值作为高原湿草甸植被优势种响应环境扰动的参考指标。展开更多
基金Supported by the National Natural Science Foundation of China(Nos.31970216,32270219)。
文摘Stylonema alsidii(Zandardini)Drew f.ramosum Zheng et Li is a common species in the genus Stylonema,but there are limited reports on morphological taxonomy and a lack of studies on life history and the regulation of early development.The early development,discoid formation,and erect thallus growth of Stylonema alsidii f.ramosum were observed under laboratory conditions.In addition,the influence of main environmental factors such as temperature and light intensity on its development was briefly studied,and various stages of its life history were observed.The result shows:(1)there are two reproductive modes:asexual reproduction and sexual reproduction;(2)the morphology of this species varies in different degrees under laboratory culture conditions;(3)sexual reproduction and asexual reproduction can coexist under suitable conditions.Five pathways of life history were inferred from experimental phenomena.Mature sporophytes form mature gametophytes by producing initially isolated or initially attached monospore,and mature gametophytes form mature sporophytes by fertilization of eggs and sperms.The sexual and asexual reproduction processes of Stylonema alsidii f.ramosum were reported for the first time,and this is also the first report on sexual reproduction in the genus Stylonema.
文摘Exploratory surveys were carried out in the Andamans and Nicobar group of islands during 2006 and 2014 to locate wild species viz. Mangifera andamanica King, Mangifera camptosperma Pierre and Mangifera griffithii Hook. Not much variation was observed for fruit shape and size for the species Mangifera andamanica, which was endemic to this region. The species M. griffithii has been reported to be only in Mt. Harriet. However, another plant of M. griffithii in the Shoalbay region was found during the second survey. The foliage & fruit characteristics of the two specimens were similar, with a slight difference in the morphological features, which could be attributed to their origin from seeds. The DNA finger printing carried out showed minor changes in the species. The phylogenetic relationships amongst five Mangifera species viz. M. indica, M. griffithii, M. camptosperma, M. odorata and M. andamanica were analyzed by employing chloroplast markers viz., petB-petD intergenic spacer, rps16 gene, trnL-trnF intergenic spacer and nuclear marker—External Transcribed Spacer (ETS). The nuclear markers and chloroplast markers based on phylogenetic analysis showed that the common mango M. indica L. was closely related to M. griffithii and M. camptosperma, which belonged to subgenus Mangifera. However, M. odorata that belonged to subgenus Limus was grouped separately along with M. andamanica. The above results are in congruent with the accepted classification of genus Mangifera reported by Kostermans and Bompard with the exception of M. andamanica, which has been earlier classified under subgenus Mangifera. Results clearly indicated that classification of M. andamanica under subgenus needed to be reconsidered.
文摘为探讨火烧干扰以及微地貌差异对高原湿草甸植被的影响,以高原湿草甸优势种华扁穗草(Blysmus sinocompressus Tang et F.T.Wang)为研究对象,分别在经历火烧干扰和未烧的湿地中选择平地和地垄作为样地,研究了不同生长期以及不同年份华扁穗草地上部的灰分含量和热值(包括干质量热值和去灰分热值)变化。结果表明:在火烧平地、火烧地垄、未烧平地和未烧地垄4类样地中,不同生长期以及不同年份间华扁穗草地上部的灰分含量和热值均有一定差异。在火烧平地、火烧地垄和未烧平地3类样地中,与生长初期相比,生长旺盛期华扁穗草地上部的灰分含量均降低,其干质量热值和去灰分热值均升高;而在未烧地垄样地中,与生长初期相比,生长旺盛期华扁穗草地上部的灰分含量显著升高,其干质量热值和去灰分热值则均略降低。从样地类型看,在生长旺盛期,平地样地中华扁穗草地上部的灰分含量均低于地垄样地,其干质量热值和去灰分热值均高于地垄样地,其中,其灰分含量在火烧平地样地中最低、在未烧地垄样地中最高;其干质量热值和去灰分热值在火烧地垄样地中均最低、在未烧平地样地中均最高,但总体无显著差异。随时间推移,火烧样地特别是火烧平地样地中华扁穗草地上部的灰分含量增加,而其干质量热值和去灰分热值则有所降低但总体上与未烧样地间无显著差异。总体上看,在火烧样地中,华扁穗草地上部的干质量热值和去灰分热值低于未烧样地;而在平地样地中,其干质量热值和去灰分热值高于地垄样地。研究结果显示:火烧干扰和微地貌差异对华扁穗草地上部的灰分含量和热值均有一定的影响,据此,建议将植物地上部的灰分含量和热值作为高原湿草甸植被优势种响应环境扰动的参考指标。
