Chen Xincong, Liu Wenwen, Pennings Steven C, Zhang Yihui
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Fujian, 361102, China.
Department of Biology and Biochemistry, University of Houston, Houston, Texas, 77204, USA.
Ecology. 2021 May;102(5):e03311. doi: 10.1002/ecy.3311. Epub 2021 Mar 23.
Patterns of flowering phenology can affect the success of plant invasions, especially when introduced species spread across a wide range of latitude into different climatic conditions. We combined a 4-yr field survey and a 3-yr common garden experiment with the invasive grass Spartina alterniflora that is now widespread along the coast of China to document the latitudinal pattern of flowering phenology, determine if phenology was related to climate or oceanographic variables, and determine whether phenology patterns were fixed versus plastic. In the field, first flowering day displayed a hump-shaped relationship with latitude, with low- and high-latitude plants flowering 100 d and 10 d earlier than plants at middle latitudes, respectively. Peak flowering day showed a similar hump-shaped relationship with latitude, with the interval between first and peak flowering day decreasing with increasing latitude. First flowering day had a hump-shaped relationship with annual growing degree days but a linear positive relationship with tidal range. In the common garden, first flowering day decreased linearly with increasing latitude of origin, as did peak flowering day, and the interval between first and peak flowering day increased with increasing latitude. First flowering day in the common garden had weak or no relationships with abiotic variables at the sites of origin. In both the field and common garden, first flowering day was later in site years for which plants were taller. These results indicate a high degree of plasticity in flowering phenology, with plants flowering later in the field at sites with intermediate temperatures and high tide ranges. Common garden results indicate some selection for earlier flowering at sites with low temperatures, consistent with a shorter growing season. Consistent with life-history theory, plants flowered later under conditions favoring vigorous growth. Earlier flowering and smaller size of plants at high and low latitudes suggests that S. alterniflora has already occupied much of the geographic range favorable for it on the East Coast of Asia.
开花物候模式会影响植物入侵的成功与否，尤其是当外来物种跨越广泛的纬度范围传播到不同气候条件下时。我们结合了一项为期4年的实地调查和一项为期3年的同质园实验，研究对象是目前在中国沿海广泛分布的入侵性草本植物互花米草，以记录开花物候的纬度模式，确定物候是否与气候或海洋学变量相关，并确定物候模式是固定的还是可塑性的。在野外，初花日与纬度呈驼峰状关系，低纬度和高纬度植物分别比中纬度植物早100天和10天开花。盛花日与纬度呈现相似的驼峰状关系，初花日和盛花日之间的间隔随着纬度的增加而减小。初花日与年生长度日呈驼峰状关系，但与潮差呈线性正相关。在同质园中，初花日随起源地纬度的增加而线性下降，盛花日也是如此，初花日和盛花日之间的间隔随纬度的增加而增大。同质园中初花日与起源地的非生物变量关系较弱或无相关性。在野外和同质园中，植株较高的年份初花日较晚。这些结果表明开花物候具有高度可塑性，植物在温度适中、潮差较大的野外地点开花较晚。同质园的结果表明，在低温地区有一些选择促使植物更早开花，这与较短的生长季节一致。与生活史理论一致，植物在有利于旺盛生长的条件下开花较晚。高纬度和低纬度地区植物较早开花且植株较小，这表明互花米草已经占据了亚洲东海岸许多对其有利的地理范围。
