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We analyzed the spatial distributions of two congeneric tree species, Neolistea aciculata and Neolistea sericea (Lauraceae), in a warm‐temperate forest on Miyajima Island, south‐western Japan. Both species were mainly found in valley sites on the island. Hence, these species shared the same topographic habitat niche. However, we found a clear difference between the spatial distributions of the two species in relation to the light environment. Neolistea aciculata was predominantly found in stands with low light, such as beneath the canopy of dense evergreen broadleaved forest. In contrast, N. sericea was predominantly associated with ample light, such as in secondary Pinus densiflora forest. In stands with moderate light conditions, both species were found. This habitat niche segregation in relation to light conditions presumably allows the coexistence of these two species in the predominantly successional forest on Miyajima Island. 相似文献
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- Several factors affecting sporulation of a wild yeast, Hansenulasaturnus, especially carbon sources and the carbon-nitrogenratio of sporulation medium were studied.
- The sporulationis stimulated at a certain definite C/N ratioof glucose medium.
- Several carbon sources such as ethanol, acetate, lactate,glycerol,succinate, glucose, gluconate and citrate are utilizedby theorganism both for growth and sporulation.
- The numberof spores in an ascus depends on the C/N ratio ofthe medium.An increase in the ratio stimulates the yield of2-and 3-sporedasci, especially of the former. One-spored ascibecome abundantas this ratio decreases.
- Lysine promotes sporulation in anacetate medium, and its presencein a large amount in glucosemedium also stimulates sporulation,while a small amount isinhibitory. When lysine was employedas the sole nitrogen source,most of the asci were 1-spored.
- It is discussed that sporulationof yeast is induced by a balanceof metabolism, rather thanby one definite "sporulation substrate".
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Kazuhiko?HOSHIZAKIEmail author Kaoru?NIIYAMA Katsuhiko?KIMURA Tamon?YAMASHITA Yukiko?BEKKU Toshinori?OKUDA Eng Seng?QUAH Nur SUPARDI Md.?Noor 《Ecological Research》2004,19(3):357-363
To clarify consistency in the size of carbon pool of a lowland tropical rainforest, we calculated changes in above-ground biomass in the Pasoh Forest Reserve, Peninsular Malaysia. We estimated the total above-ground biomass of a mature stand using tree census data obtained in a 6-ha plot every 2years from 1994 to 1998. The total above-ground biomass decreased consistently from 1994 (431Mgha–1) to 1998 (403Mgha–1) (1Mg=103 kg). These are much lower than that in 1973 for a 0.2ha portion of the same area, suggesting that the the total above-ground biomass reduction might have been consistent in recent decades. This trend contrasted with a major trend for neotropical forests. During 1994–1998, the forest gained 23.0 and 0.88Mgha–1 of the total above-ground biomass by tree growth and recruitment, respectively, and lost 51.9Mgha–1 by mortality. Overall, the biomass decreased by 28.4Mgha–1 (i.e. 7.10Mgha–1·year–1), which is almost equivalent to losing a 76-cm-diameter living tree per hectare per year. Analysis of positive and negative components of biomass change revealed that deaths of large trees dominated the total above-ground biomass decrease. The forest biomass also varied spatially, with the total above-ground biomass density ranging 212–655Mgha–1 on a 0.2-ha basis (n= 30 subplots, 1998) and 365–440Mgha–1 on a 1ha basis. A large decrease of the total above-ground biomass density (>50Mg per ha per 2years) in several 0.2-ha subplots contributed to the overall decrease in the 6-ha total above-ground biomass. In the present study, we discuss the association between forest dynamics and biomass fluctuation, and the implication for carbon cycling in mature forests with emphasis on forest monitoring and assessments of soil and decomposition systems. 相似文献
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THE polysaccharides obtained from some basidiomycetes, Pleurotus ostreatus (Jacq. ex Fr.) Quel.1, Flammulina velutipes (Curt, ex Fr.) Sing.2, Lentinus edodes (Berk.) Sing.2–4, Polia cocos, Wolf (Bukuryo)5 and Schizophyllum commune Fr.7, strongly inhibit the growth of sarcoma 180 and their anti-tumour activity is host-mediated8,9. 相似文献
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OHSUGI RYU; UENO OSAMU; KOMATSU TOSHINORI; SASAKI HARUTO; MURATA TAKAO 《Annals of botany》1997,79(2):179-184
The relationship between leaf anatomy, ultrastructure and carbondiscrimination was investigated in leaves of two F1hybrids (F1-1and F1-2) between two different types of the grassPanicum [anNAD-malic enzyme (ME) C4species], which differ in bundle sheathultrastructure. The female parent was Kabulabula grass, whichhas centrifugal chloroplasts in bundle sheath cells and is designatedan NAD-ME(F) species, while the male parent was Makarikari grass,which has centripetal chloroplasts in the bundle sheath cellsand is designated an NAD-ME(P) species. Suberin lamellae arepresent in Kabulabula grass but are lacking in Makarikari grass.Both F1hybrids had the same chromosome number (2n =36) as theparents but exhibited both univalent (about 45%) and bivalent(about 55%) chromosome pairing which was the major basis forthe identification of F1hybrids. In F1-1, elongated bundle sheathcell chloroplasts are arranged mainly in a centripetal position,similar to those in the male parent, Makarikari grass. In contrast,most of the bundle sheath cells in F1-2 are packed with starch-containingchloroplasts, although in some cells chloroplasts tended tobe centripetally arranged. In both F1hybrids, suberin lamellaewere found in the bundle sheath cell walls, similar to the femaleparent, Kabulabula grass. The 13C values of both F1hybrids were-11.4 to -11.7, almost the same as those of Kabulabula grass(-11.4), but significantly higher than those of Makarikari grass(-12.7). These results indicate that the chloroplast orientationin the bundle sheath cells and the presence of suberin lamellaeare not obligatorily linked in their expression and suggestthat suberin lamellae may play an important role in discriminationagainst13C. Panicum ; NAD-malic enzyme species; hybrid; chloroplast position; 13C discrimination; suberin lamellae 相似文献
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Direct Evidence for the Presence of Germ Cell Determinant in Vegetal Pole Cytoplasm of Xenopus laevis and in a Subcellular Fraction of It 总被引:2,自引:2,他引:0
KOHJI IKENISHI SAKIKO NAKAZATO TAKASHI OKUDA 《Development, growth & differentiation》1986,28(6):563-568
To test for the presence of germ cell determinant in Xenopus embryos, vegetal pole cytoplasm containing the "germ plasm", or a subcellular fraction of it, was microinjected into single somatic blastomeres isolated from 32-cell embryos. Injected or non-injected (control) blastomeres were cultured in 3 H-thymidine until normal control embryos reached the neurula stage. The labeled explants were then implanted into unlabeled host neurulae, which were allowed to develop to the tadpole stage. Labeled PGCs of explant origin in the genital ridges of the experimental tadpoles were examined by autoradiography.
Isolated blastomeres were injected with vegetal pole cytoplasm of 32-cell embryos or with a 20,000 g pellet made from vegetal pole cytoplasm of 2-cell embryos. Labeled PGCs were found in 7.6% and 2.3% of the experimental tadpoles, respectively. No labeled PGCs were found in the control tadpoles, except for one tadpole in the first experiment. These results strongly suggest that the vegetal pole cytoplasm and its subcellular fractions act as germ cell determinant. 相似文献
Isolated blastomeres were injected with vegetal pole cytoplasm of 32-cell embryos or with a 20,000 g pellet made from vegetal pole cytoplasm of 2-cell embryos. Labeled PGCs were found in 7.6% and 2.3% of the experimental tadpoles, respectively. No labeled PGCs were found in the control tadpoles, except for one tadpole in the first experiment. These results strongly suggest that the vegetal pole cytoplasm and its subcellular fractions act as germ cell determinant. 相似文献
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A new anhydrobiotic midge from Malawi,Polypedilum pembai sp.n. (Diptera: Chironomidae), closely related to the desiccation tolerant midge,Polypedilum vanderplanki Hinton
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RICHARD CORNETTE NAO YAMAMOTO MASARU YAMAMOTO TADASHI KOBAYASHI NINEL A. PETROVA OLEG GUSEV SACHIKO SHIMURA TAKAHIRO KIKAWADA DYLO PEMBA TAKASHI OKUDA 《Systematic Entomology》2017,42(4):814-825
The sleeping chironomid (Polypedilum vanderplanki Hinton) lives on temporary rock pools in the semi‐arid tropical regions of Africa. Its larvae are able to survive the dry season in a completely desiccated ametabolic state known as anhydrobiosis. So far, P. vanderplanki was the only species among all insects showing demonstrated anhydrobiotic ability. Here, we show that a new related species originating from Malawi, Polypedilum pembai sp.n. , is also anhydrobiotic and that its desiccation tolerance mechanism is probably similar to what is observed in P. vanderplanki. The new species, P. pembai sp.n. , is described with special attention to the common and different morphological features, compared with P. vanderplanki. Phylogenetic analysis showed that both species are closely related, suggesting that anhydrobiosis evolved only once in their common ancestor about 49 Ma somewhere in Africa, before the divergence of two species, one in the sub‐Saharan area and another in southeastern Africa. 相似文献