Speciation and xerophilous adaptation of plants in the Lomas Vegetation along the Pacific Coast of South America

1.洛马斯植被于1991年在智利北部广泛形成。我们调查了这些群落的宏观分布以及智利北部科皮亚波以西约50公里处的Cerro Punta de Vacas的局部分布。比较气象资料，群落的宏观尺度格局似乎不受地形条件的影响，是由6月和7月的降雨量产生的。Punta deVacas群落的局部尺度格局明显受地形条件的影响，表现出与“雾-降水”格局相同的地形效应。对塞罗蓬德巴卡斯洛马斯植被东南坡的植物生产力进行了调查。有四种植被类型：Calandrinia、Cristaria、Cordenia(Tiquilla)和Fortnetia。对每种类型的生物量和水势进行了测量。生物量与低生产力草地的生物量相近。C-…的水势随着气温的升高，更多的万寿菊和狗尾草减少，而其他物种在整个白天几乎保持不变。根据优势种的不同，将巴卡斯角地区的植被划分为3种类型：石斑藻、甲藻和Cordenia(Tiquilla)群落。在10月30日和11月5日，根据物种数量和每个物种的最高高度和盖度，对每个林分的植被进行调查，并采集了10个土样(25 cm×25 cm×2 cm)。种子是从土壤样本中挑选出的成分中挑选出来的。虽然这些埋藏的种子鉴定不尽如人意，但从竹节林采集的样品中，物种和种子数量都较多。为了检验种子在地下的寿命，分别将石竹、鸡冠花和水仙的种子埋在地下5 cm深的地方。预计将在下一次调查中检查每个物种的种子发芽率，以估计其种子寿命。较少

1. The lomas vegetation was broadly formed in northern Chile in 1991. We investigated the macro scale distribution of these communities, as well as the local-scale distribution in Cerro Punta de Vacas, about 50km west of Copiapo, northern Chile. Comparing the meteological data, the macro-scale pattern of the communities, which seemed not to be influenced by topographical conditions, were produced by June and July rainfall. The local-scale pattern of the communities of Punta deVacas were markedly influenced by topographical conditions, exhibited the same topographic effect as found in "fog-precipitation" pattern.2. An investigation on plant productivity was carried out on the south-east faced slope of lomas vegetation at Cerro Punta de Vacas. There were four types of vegetation : Calandrinia, Cristaria, Cordenia (Tiquilla) and Fortnetia. Biomass and water potential were measured on each type. The values of biomass were similar to those of low productivity grassland. Water potential of C … More ristaria and Cordenia decreased according as rising of air temperature, while the other species maintained nearly same value throughout the daytime.3. The vegetation of Punta de Vacas area is classified into three types based on the dominant species : Calandrinia, Cristaria and Cordenia (Tiquilla) community. Both on 30th of October and 5th of November, the vegetation at each stand was surveyed according to number of species and the highest height and coverage of each species, and ten soil samples (25cm x 25cm x 2cm) were taken. Seeds were sorted out of the components selected from soil samples. Although the identification of these buried seeds was unsatisfactory, there were more species and seeds in number in the sample collected from the Calandrinia stand. In order to examine seed longevity under the ground, 200-300 seeds of each Calandrinia, Cristaria and Nolana were buried in the depth of 5cm under the ground surface. The seed germination rates of each species is expected to be examined in the occasion of next survey, for estimation of their seed longevity. Less