Matzrafi Maor, Ziv Shaharit, Abu-Nassar Jackline, Gillett Daryl, Gamliel Abraham
Department of Plant Pathology and Weed Research, Agricultural Research Organization - Volcani Institute, Newe Ya'ar Research Center, Ramat Yishay, Israel.
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel.
BMC Plant Biol. 2024 Dec 3;24(1):1160. doi: 10.1186/s12870-024-05857-0.
Melilotus sulcatus (Fabaceae) is an annual weed species prevalent in the Mediterranean Basin and Asia, characterized by a hard seed coat, indicating physical seed dormancy and long seed-bank longevity. This weed exhibits high phenotypic plasticity, thriving across various climatic regions in Israel. This study investigates seed germination of M. sulcatus populations under different temperatures. Moreover, we have studied the phenology, and reproductive biology of M. sulcatus populations in a common garden experiment. Seeds of M. sulcatus were collected from onion fields at Kibbutz Grofit located in the hyper-arid Southern Arava region, with ~ 30 mm average annual rainfall, and from Kibbutz Yifat, in the Jezreel Valley, where annual rainfall is 450-650 mm. Progeny generations were grown in pollen-proof cages at Newe Ya'ar Research Center also located at the Jezreel Valley.
Differences in seed area and average weight were observed among populations and generations, with field populations producing heavier seeds compared to progeny populations. The optimal temperature (T) for seed germination varied among populations, with the highest T recorded for the Grofit field population (23.40℃) collected at the warm site and the lowest for the Yifat field population (17.67℃) collected at the cold site, while the two progeny populations showed similar T values. Phenology and reproductive biology were tested using seeds of the two field populations. Despite the vigorous growth of the Grofit population, there were no significant differences in average final weight (4.59 g for Grofit and 4.23 g for Yifat) and height (51.8 cm for Grofit and 50.3 cm for Yifat) between populations. Grofit progeny plants exhibited a statistically significantly higher number of seeds per pod, combined with larger seed area and average weight.
Overall, our findings underscore the adaptive strategies employed by M. sulcatus populations in response to their environment. Vigorous plant growth, a higher number of seeds per pod, and larger seed area and average weight were observed in individuals from the Grofit population compared to the Yifat population. The greater fitness of Grofit population, originated from hyper-arid conditions, highlights the significant impact of environmental factors on species adaptation.
沟酸模（豆科）是一种一年生杂草，在地中海盆地和亚洲普遍存在，其特点是种皮坚硬，表明存在物理种子休眠且种子库寿命长。这种杂草表现出高表型可塑性，在以色列的各种气候区域都能生长。本研究调查了不同温度下沟酸模种群的种子萌发情况。此外，我们在一个共同花园实验中研究了沟酸模种群的物候和生殖生物学。沟酸模的种子分别采集自位于超干旱的南阿拉瓦地区、年平均降雨量约30毫米的基布兹格罗菲特的洋葱田，以及年降雨量为450 - 650毫米的耶斯列谷的基布兹伊法特。子代在同样位于耶斯列谷的内韦亚尔研究中心的防花粉笼中生长。
在种群和世代之间观察到种子面积和平均重量存在差异，田间种群产生的种子比子代种群的种子更重。种子萌发的最佳温度（T）因种群而异，在温暖地点采集的格罗菲特田间种群记录的最高温度为23.40℃，在寒冷地点采集的伊法特田间种群的最低温度为17.67℃，而两个子代种群的T值相似。使用两个田间种群的种子测试了物候和生殖生物学。尽管格罗菲特种群生长旺盛，但种群之间的平均最终重量（格罗菲特为4.59克，伊法特为4.23克）和高度（格罗菲特为51.8厘米，伊法特为50.3厘米）没有显著差异。格罗菲特子代植株每荚种子数量在统计学上显著更多，同时种子面积和平均重量更大。
总体而言，我们的研究结果强调了沟酸模种群为适应环境所采用的适应性策略。与伊法特种群相比，格罗菲特种群的个体表现出旺盛的植株生长、每荚种子数量更多以及种子面积和平均重量更大。源自超干旱条件的格罗菲特种群更强的适应性突出了环境因素对物种适应的重大影响。
