Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses...Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses litterbags with two different mesh sizes (0.04 and 3 mm) to control the meso- and microfauna entering the bags to quantify the contribution of soil fauna to the degradation of recalcitrant components (including condensed tannins, total phenol, lignin and cellulose) during litter decomposition. The experiment was conducted in seven different forest gap sizes in Pinus massoniana plantations over 1 year. One closed-canopy site (CC) and forest gap sizes of 100, 225, 400, 625, 900, 1225 and 1600 m^2 were created in a P. massoniana plantation in the Sichuan basin of China;the CC was treated as the control. Cinnamomum camphora foliage from local native trees was used in all forest gap experiments. We found the following:(1) Gap size had significant effects on the degradation rates (E) of condensed tannins and lignin and on the contributions of soil fauna;medium-sized gaps also presented high degradation rates. Soil fauna obviously contributed to the degradation of recalcitrant foliar litter components in medium-sized gaps.(2) The highest contribution to degradation (40.98%) was recorded for lignin, and the lowest contribution (0.29%) was recorded for condensed tannins. The results indicate that medium-sized gaps (900 m^2) were conducive to the degradation of recalcitrant litter components by soil fauna.展开更多
We studied seed storage behaviour of a multipurpose tree Calophyllum inophyllum （Clusiaseae）. Seeds were collected at Roslyn bay （2307′60＂ S, 150°43′60＂ E） Central Queensland. Seed drying and desieeation ...We studied seed storage behaviour of a multipurpose tree Calophyllum inophyllum （Clusiaseae）. Seeds were collected at Roslyn bay （2307′60＂ S, 150°43′60＂ E） Central Queensland. Seed drying and desieeation tolerance tests were carried out according to International Seed Testing Association （ISTA） rules. We found C. inophyllum seeds to be recalcitrant and vulnerable to chilling injury, hence, unsuited for cold storage. C. inophyllum seeds maintained their viability for an appreciable period （〉 8 months） if stored in wanner environments.展开更多
We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation ...We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation （open lab condition） seeds with MC 23% showed 40% germination. After further drying to MC 21% germination was reduced to 16%. Complete loss in viability resulted when seed moisture was reduced to 18%. The seeds stored at -10℃, 0℃, 10℃ and 28±2℃ （open lab condition） lost their viability within 10 days. Seeds stored in sealed polythene hags and moist sand retained viability for more days than did seeds stored under all other storage conditions. Sensitivity of seeds to lower temperature and desiccation suggest that the storage behavior of K. attenuata seeds is recalcitrant. Seeds stored in moist conditions can, at best, be stored for a period of two months.展开更多
Shoot organogenesis is critical for the shortening of long breeding cycles and circumvent the barrier of cloning mature Eucalyptus cloeziana trees.It enables large-scale production of plants from transformed tissues.T...Shoot organogenesis is critical for the shortening of long breeding cycles and circumvent the barrier of cloning mature Eucalyptus cloeziana trees.It enables large-scale production of plants from transformed tissues.This study evaluates the effect ofα-naphthaleneacetic acid(NAA),thidiazuron(TDZ)and benzylaminopurine(BAP)on the organogenesis of E.cloeziana from hypocotyls and cotyledonary leaves.In the induction stage,hypocotyls and cotyledonary leaves were established in a Murashige and Skoog(MS)culture medium supplemented with NAA or TDZ.Callus tissues were cultivated in a MS culture medium containing only BAP or different concentrations of BAP/NAA in the differentiation stage.Adventitious buds were multiplied in vitro and elongated in a WPM culture medium supplemented with 0.89μM BAP and 0.05μM NAA.Cotyledonary leaves exhibited the best in vitro regeneration.The induction of adventitious buds occurred only in calluses induced from TDZ.In the differentiation stage,4.4μM BAP treatment promoted an increase of adventitious bud regeneration.Micro-cuttings from regenerated shoots were acclimatized and rooted ex vitro in mini-incubators.The results confirm the establishment of an efficient protocol for the in vitro regeneration of E.cloeziana by indirect organogenesis,providing new insights regarding cloning of this species.展开更多
Decomposition dynamics were compared among green tree leaves, partially decomposed tree leaf litter （i.e., decayed tree leaf litter on forest floor） and a mixture of the two in a warm temperate forest ecosystem in c...Decomposition dynamics were compared among green tree leaves, partially decomposed tree leaf litter （i.e., decayed tree leaf litter on forest floor） and a mixture of the two in a warm temperate forest ecosystem in central China to test the influence of litter chemical quality on the degree of decomposition. The study was conducted in situ at two contrasting forest sites, an oak forest dominated by Quercus aliena var. acuteserrata Maxim., and a mixed pine and oak forest dominated by Pinus armandii Franch. and Q. aliena var. acuteserrata. We found marked differences in the rate of decomposition among litter types at both forest sites; the litter decom- position constant, k, was about 39 % greater at the oak forest site and more than 70 % greater at the pine-oak forest site, for green leaves than for partially decomposed leaf litter. The decomposition dynamics and temporal changes in litter chemistry of the three litter types also greatly differed between the two forest sites. At both forest sites, the higher rate of decomposition for the green leaves was associated with a and lower carbon to N ratio higher nitrogen （N） content （C/N） and acid-unhydrolyz- able residue to N ratio （AUR/N）. We did not find any non- additive effects when mixing green leaves and partially decomposed leaf litter. Our findings support the con- tention that litter chemical quality is one of the most important determinants of litter decomposition in forest ecosystems at the local or regional scale, but the effect of litter chemical quality on decomposition differs between the contrasting forest types and may vary with the stage of decomposition.展开更多
基金supported by the National Natural Science Foundation of China(Grant Number 31370628)the National Science and Technology Support Project of China(Grant Number2011BAC09B05)the Sichuan Provincial Science and Technology Support Project(Grant Number 12ZC0017)
文摘Forest gaps are important in forest dynamics and management, but little is known about how soil fauna influence the degradation of recalcitrant litter components in different-sized forest gaps. This investigation uses litterbags with two different mesh sizes (0.04 and 3 mm) to control the meso- and microfauna entering the bags to quantify the contribution of soil fauna to the degradation of recalcitrant components (including condensed tannins, total phenol, lignin and cellulose) during litter decomposition. The experiment was conducted in seven different forest gap sizes in Pinus massoniana plantations over 1 year. One closed-canopy site (CC) and forest gap sizes of 100, 225, 400, 625, 900, 1225 and 1600 m^2 were created in a P. massoniana plantation in the Sichuan basin of China;the CC was treated as the control. Cinnamomum camphora foliage from local native trees was used in all forest gap experiments. We found the following:(1) Gap size had significant effects on the degradation rates (E) of condensed tannins and lignin and on the contributions of soil fauna;medium-sized gaps also presented high degradation rates. Soil fauna obviously contributed to the degradation of recalcitrant foliar litter components in medium-sized gaps.(2) The highest contribution to degradation (40.98%) was recorded for lignin, and the lowest contribution (0.29%) was recorded for condensed tannins. The results indicate that medium-sized gaps (900 m^2) were conducive to the degradation of recalcitrant litter components by soil fauna.
文摘We studied seed storage behaviour of a multipurpose tree Calophyllum inophyllum （Clusiaseae）. Seeds were collected at Roslyn bay （2307′60＂ S, 150°43′60＂ E） Central Queensland. Seed drying and desieeation tolerance tests were carried out according to International Seed Testing Association （ISTA） rules. We found C. inophyllum seeds to be recalcitrant and vulnerable to chilling injury, hence, unsuited for cold storage. C. inophyllum seeds maintained their viability for an appreciable period （〉 8 months） if stored in wanner environments.
文摘We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation （open lab condition） seeds with MC 23% showed 40% germination. After further drying to MC 21% germination was reduced to 16%. Complete loss in viability resulted when seed moisture was reduced to 18%. The seeds stored at -10℃, 0℃, 10℃ and 28±2℃ （open lab condition） lost their viability within 10 days. Seeds stored in sealed polythene hags and moist sand retained viability for more days than did seeds stored under all other storage conditions. Sensitivity of seeds to lower temperature and desiccation suggest that the storage behavior of K. attenuata seeds is recalcitrant. Seeds stored in moist conditions can, at best, be stored for a period of two months.
基金CAPES (Coordination for the Improvement of Higher Personnel, Brazil) for their scholarshipCNPq (National Counsel of Technological and Scientific Development, Brazil)IPEF (Forestry Science and Research Institute, Brazil) for technical support
文摘Shoot organogenesis is critical for the shortening of long breeding cycles and circumvent the barrier of cloning mature Eucalyptus cloeziana trees.It enables large-scale production of plants from transformed tissues.This study evaluates the effect ofα-naphthaleneacetic acid(NAA),thidiazuron(TDZ)and benzylaminopurine(BAP)on the organogenesis of E.cloeziana from hypocotyls and cotyledonary leaves.In the induction stage,hypocotyls and cotyledonary leaves were established in a Murashige and Skoog(MS)culture medium supplemented with NAA or TDZ.Callus tissues were cultivated in a MS culture medium containing only BAP or different concentrations of BAP/NAA in the differentiation stage.Adventitious buds were multiplied in vitro and elongated in a WPM culture medium supplemented with 0.89μM BAP and 0.05μM NAA.Cotyledonary leaves exhibited the best in vitro regeneration.The induction of adventitious buds occurred only in calluses induced from TDZ.In the differentiation stage,4.4μM BAP treatment promoted an increase of adventitious bud regeneration.Micro-cuttings from regenerated shoots were acclimatized and rooted ex vitro in mini-incubators.The results confirm the establishment of an efficient protocol for the in vitro regeneration of E.cloeziana by indirect organogenesis,providing new insights regarding cloning of this species.
基金supported by the National Basic Research Program(Grant No.2011CB403205)
文摘Decomposition dynamics were compared among green tree leaves, partially decomposed tree leaf litter （i.e., decayed tree leaf litter on forest floor） and a mixture of the two in a warm temperate forest ecosystem in central China to test the influence of litter chemical quality on the degree of decomposition. The study was conducted in situ at two contrasting forest sites, an oak forest dominated by Quercus aliena var. acuteserrata Maxim., and a mixed pine and oak forest dominated by Pinus armandii Franch. and Q. aliena var. acuteserrata. We found marked differences in the rate of decomposition among litter types at both forest sites; the litter decom- position constant, k, was about 39 % greater at the oak forest site and more than 70 % greater at the pine-oak forest site, for green leaves than for partially decomposed leaf litter. The decomposition dynamics and temporal changes in litter chemistry of the three litter types also greatly differed between the two forest sites. At both forest sites, the higher rate of decomposition for the green leaves was associated with a and lower carbon to N ratio higher nitrogen （N） content （C/N） and acid-unhydrolyz- able residue to N ratio （AUR/N）. We did not find any non- additive effects when mixing green leaves and partially decomposed leaf litter. Our findings support the con- tention that litter chemical quality is one of the most important determinants of litter decomposition in forest ecosystems at the local or regional scale, but the effect of litter chemical quality on decomposition differs between the contrasting forest types and may vary with the stage of decomposition.
