木本植物种子产量的时间和空间变化格局对植物更新以及群落组成和结构有着重要影响,是种子雨研究的一个重要方面。2006年6月在古田山亚热带常绿阔叶林24hm2样地布置了130个面积为0.5m2的种子雨收集器,每周收集一次。利用4年的种子雨数据...木本植物种子产量的时间和空间变化格局对植物更新以及群落组成和结构有着重要影响,是种子雨研究的一个重要方面。2006年6月在古田山亚热带常绿阔叶林24hm2样地布置了130个面积为0.5m2的种子雨收集器,每周收集一次。利用4年的种子雨数据,研究了种子雨的时间和空间变异。主要结果如下:(1)共收集到124227粒成熟种子,属于29科51属63种,每月降水量与平均每月种子数、物种数均呈显著负相关;(2)种子产量在每年干季(秋季)有明显的高峰,有10个物种在湿季扩散种子,不同物种结实物候起始和终止时间有差异;(3)基于4年的种子雨数据,几乎所有物种的种子雨均存在很大的年际变异,收集到的所有物种的种子产量年际变异系数的中位数为1.72;(4)种子雨在不同收集器之间有很大的变异,变异系数的中位数为8.06;几乎所有物种的空间变异都远远大于时间变异,这可能是由于母树的稀有性、种子传播距离的差异,以及地形等因素造成。通过与巴拿马Barro Colorado Island 50hm2样地108个物种种子产量的年际变异系数相比较,古田山种子雨数据支持了高纬度地区种子产量变异高于低纬度地区的假说。展开更多
Strawberry (Fragaria spp.) is one of the most important fruits classified as exotic fruits imported into Cameroon. To have an inventory of its cultivation in Cameroon, a survey study was carried out among eight farms ...Strawberry (Fragaria spp.) is one of the most important fruits classified as exotic fruits imported into Cameroon. To have an inventory of its cultivation in Cameroon, a survey study was carried out among eight farms of Fragaria spp. from January 2021 to February 2022. The plant was introduced in Cameroon in 2018. There are 13 varieties of Fragaria spp. currently cultivated. Among these 13 varieties, eleven are hybrids of Fragaria x ananassa (“Amiga”, “Amine”, “Camarosa”, “Chandler”, “Charlotte”, “Elsanta”, “Gariguette”, “Madame Moutot”, “Ostara”, “Ruby gem” and “San Andreas”), and two of the hybrids of Fragaria vesca (“Maestro” and “Mara des bois”). The cropping system, irrigation system, and type of fertilizers applied differ from one strawberry farm to another. Biofertilizers (such as mycorrhizal), inorganic and organic fertilizers are actually used to improve production. The potential annual production of strawberries from January 2021 to February 2022, estimated based on the survey data, was 21.216 tons for all growers. Among these eight production farms, the Lolodorf BIO Farm presents 6000 kg (six tons) of strawberries and 100,000 stolons (seedlings) produced, from seven varieties of Fragaria spp. cultivated, with 6 varieties which are hybrids variety Fragaria x ananassa (“Amiga”, “Amine”, “Chandler”, “Gariguette”, “Madame Moutot”, and “Ruby gem”), and one which is a hybrid of Fragaria vesca (“Mara des bois”). Certain diseases were also observed and recorded depending on the growing areas.展开更多
Annual production and life cycle of five dominant species of Chironomidae (Chironomus plumosus, Cryptochironomus sp.,Tokunagayusurika akamusi, Procladius sp.,Clinotanypus sp.) were studied with samples collected month...Annual production and life cycle of five dominant species of Chironomidae (Chironomus plumosus, Cryptochironomus sp.,Tokunagayusurika akamusi, Procladius sp.,Clinotanypus sp.) were studied with samples collected monthly from April, 1996 to March, 1997 in Houhu Lake at four stations. Based on instar-frequency data,C. plumosus was univoltine, while the other four were bivoltine. Production rates in grams wet weight m?2a?1 calculated by the size-frequency method wereC. plumosus, 2.170;Cryptochironomus sp., 0.602;T. akamusi, 3.160;Procladius sp., 0.964;Clinotanypus sp., 0.390. Their P/B ratios were 3.9, 4.9, 4.4, 5.3 and 6.6, respectively.展开更多
文摘木本植物种子产量的时间和空间变化格局对植物更新以及群落组成和结构有着重要影响,是种子雨研究的一个重要方面。2006年6月在古田山亚热带常绿阔叶林24hm2样地布置了130个面积为0.5m2的种子雨收集器,每周收集一次。利用4年的种子雨数据,研究了种子雨的时间和空间变异。主要结果如下:(1)共收集到124227粒成熟种子,属于29科51属63种,每月降水量与平均每月种子数、物种数均呈显著负相关;(2)种子产量在每年干季(秋季)有明显的高峰,有10个物种在湿季扩散种子,不同物种结实物候起始和终止时间有差异;(3)基于4年的种子雨数据,几乎所有物种的种子雨均存在很大的年际变异,收集到的所有物种的种子产量年际变异系数的中位数为1.72;(4)种子雨在不同收集器之间有很大的变异,变异系数的中位数为8.06;几乎所有物种的空间变异都远远大于时间变异,这可能是由于母树的稀有性、种子传播距离的差异,以及地形等因素造成。通过与巴拿马Barro Colorado Island 50hm2样地108个物种种子产量的年际变异系数相比较,古田山种子雨数据支持了高纬度地区种子产量变异高于低纬度地区的假说。
文摘Strawberry (Fragaria spp.) is one of the most important fruits classified as exotic fruits imported into Cameroon. To have an inventory of its cultivation in Cameroon, a survey study was carried out among eight farms of Fragaria spp. from January 2021 to February 2022. The plant was introduced in Cameroon in 2018. There are 13 varieties of Fragaria spp. currently cultivated. Among these 13 varieties, eleven are hybrids of Fragaria x ananassa (“Amiga”, “Amine”, “Camarosa”, “Chandler”, “Charlotte”, “Elsanta”, “Gariguette”, “Madame Moutot”, “Ostara”, “Ruby gem” and “San Andreas”), and two of the hybrids of Fragaria vesca (“Maestro” and “Mara des bois”). The cropping system, irrigation system, and type of fertilizers applied differ from one strawberry farm to another. Biofertilizers (such as mycorrhizal), inorganic and organic fertilizers are actually used to improve production. The potential annual production of strawberries from January 2021 to February 2022, estimated based on the survey data, was 21.216 tons for all growers. Among these eight production farms, the Lolodorf BIO Farm presents 6000 kg (six tons) of strawberries and 100,000 stolons (seedlings) produced, from seven varieties of Fragaria spp. cultivated, with 6 varieties which are hybrids variety Fragaria x ananassa (“Amiga”, “Amine”, “Chandler”, “Gariguette”, “Madame Moutot”, and “Ruby gem”), and one which is a hybrid of Fragaria vesca (“Mara des bois”). Certain diseases were also observed and recorded depending on the growing areas.
文摘Annual production and life cycle of five dominant species of Chironomidae (Chironomus plumosus, Cryptochironomus sp.,Tokunagayusurika akamusi, Procladius sp.,Clinotanypus sp.) were studied with samples collected monthly from April, 1996 to March, 1997 in Houhu Lake at four stations. Based on instar-frequency data,C. plumosus was univoltine, while the other four were bivoltine. Production rates in grams wet weight m?2a?1 calculated by the size-frequency method wereC. plumosus, 2.170;Cryptochironomus sp., 0.602;T. akamusi, 3.160;Procladius sp., 0.964;Clinotanypus sp., 0.390. Their P/B ratios were 3.9, 4.9, 4.4, 5.3 and 6.6, respectively.
