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131.
The Global Strategy for Plant Conservation (GSPC) set an ambitious target to achieve a conservation assessment for all known plant species by 2020. We consolidated digitally available plant conservation assessments and reconciled their scientific names and assessment status to predefined standards to provide a quantitative measure of progress toward this target. The 241,919 plant conservation assessments generated represent 111,824 accepted land plant species (vascular plants and bryophytes, not algae). At least 73,081 and up to 90,321 species have been assessed at the global scale, representing 21–26% of known plant species. Of these plant species, at least 27,148 and up to 32,542 are threatened. Eighty plant families, including some of the largest, such as Asteraceae, Orchidaceae, and Rubiaceae, are underassessed and should be the focus of assessment effort if the GSPC target is to be met by 2020. Our data set is accessible online (ThreatSearch) and is a baseline that can be used to directly support other GSPC targets and plant conservation action. Although around one‐quarter of a million plant assessments have been compiled, the majority of plants are still unassessed. The challenge now is to build on this progress and redouble efforts to document conservation status of unassessed plants to better inform conservation decisions and conserve the most threatened species. 相似文献
132.
稻田甲烷排放通量与农业管理措施的关系 总被引:1,自引:0,他引:1
邵可声 《生态与农村环境学报》1993,(Z1)
1990至1992年对北京地区的麦后稻区及单季稻区进行了三年的稻田甲烷排放通量的测定,麦后稻区的甲烷排放通量约17.5mg/m~2·h;单季稻小区约在8.5-10mg/m~2·h。有机底肥的用量是影响甲烷排放通量的首要因素,旱直播及仅使用化肥可降低甲烷排放通量。在一定量有机底肥的条件下,采用间歇灌溉的方法既可保持或提高水稻的产量,又可抑制或降低甲烷的排放通量,但也观测到干干湿湿的状态下温室气体N_2O的排放通量有所增加。 相似文献
133.
低压离子色谱法测定水和酸雨样品中的Li~+,Na~+,NH_4~+,K~+,Ca~(2+)和Mg~(2+)离子 总被引:3,自引:0,他引:3
本文介绍了低压离子色谱仪测定水样(井水、湖水、矿泉水、自来水)和酸雨中锂、钠、铵、钙、钾和镁离子的方法、欲测阳离子在阳离子交换柱上被分离,分别用1.4mmol·1~(-1)HNO_3和0.6mmol·1~(-1)乙二胺+1.2mmol·1~(-1)HNO_3溶液作流动相,流速为1.6ml·min~(-1).各离子的流分用电导检测.进样量为10μl时,Li~+,Na~+,NH_4~+,K~+,Ca~(2+)和Mg~(2+)离子的检出限(2倍噪音比),分别为0.020,0.050,0.100,0.250,2.5和1.0μg·ml~(-1). 相似文献
134.
135.
孟范平 《生态与农村环境学报》1994,(4)
根据C_3植物和C_4植物对高浓度CO_2的不同反应,评述了富CO_2大气对生态系统的影响。结论是大气CO_2浓度增加将导致生态系统发生一系列变化,包括生物多样世的减少、营养循环受阻、虫灾发生和温室效应加剧等。 相似文献
136.
137.
138.
1 IntroductionTransitionmetalswereamongthemostconcernelementsinenvironmentalanalysisduetotheirpotentialrolestoplantandanimals[1 ].Theserolesoftransitionmetalsinenvironmentdependedontheirconcentrationinthesoil,waterandlivingthings.Currently ,themostutiliz… 相似文献
139.
Summary. Sequestration of plant toxins in herbivores is often
correlated with aposematic coloration and gregarious behaviour. Larvae
of Pieris brassicae show these conspicuous morphological and behavioural
characteristics and were thus suggested to sequester glucosinolates that
are characteristic secondary metabolites of their host plants. P. rapaeare camouflaged and solitary, and are thus not expected to sequester. To
test this hypothesis and to check the repeatabi-lity of a study that did
report the presence of the glucosinolate sinigrin in P. brassicae,
larvae were reared on three species of Brassicaceae (Sinapis alba,
Brassica nigra and Barbarea stricta), and different leaf and insect
samples were taken for glucosinolate analysis. The major host plant
glucosinolates could only be found in traces or not at all in larval
haemolymph, bled or starved larvae, faeces or pupae of both species or
P. brassicae regurgitant. Haemolymph of both Pieris spp. was not
rejected by the ant Myrmica rubra in dual-choice assays; the regurgitant
of P. brassicae was rejected. This suggests the presence of compounds
other than glucosinolates that might be sequestered in or produced by P.
brassicae only. In faeces of both Pieris spp. a compound which yielded
4-hydroxybenzylcyanide (HBC) upon incubation with sulfatase was detected
in high concentrations when larvae had been reared on S. alba. This
compound may be derived from hydrolysis of sinalbin, the main
glucosinolate of that plant. The unidentified HBC progenitor was
apparently not sequestered in the two Pieris spp., and was not detected
in faeces of larvae reared on B. nigra or B. stricta.
Received 18 July 2002; accepted 11 September 2002. 相似文献
140.
利用衍生化气相色谱法对黄磷诱发氧化苯酚降解产物进行了研究,在磷酸存在下,以甲醇作酯类衍行生试剂,分别和SE-52和HP-17石英毛细管双柱结合GC-MS进行分离定性定量,黄磷诱发氧化苯酚降解产物以羧酸为主,在反应温度50℃时,表现为一级反应特征,速率常数(K):0.077min^-1,半衰期(t1/2):9.0min。 相似文献