Abstract: Dichondra （Dichondra repens） is a warm-season perennial ground cover plant belonging to the Convolvulaceae， which is widely utilized in landscaping， soil and water conservation， and orchard ground cover. Low-temperature stress is a main limiting factor restricting its promotion and utilization. In this study， we evaluated turf performance and cold adaptability of 12 dichondra genotypes， including nine wild materials which were collected from Southwest China， two nationally certified cultivars， and one widely-used introduced cultivar. The results found significant variations in leaf area， uniformity， leaf color， green period， canopy height， and establishment rate among the 12 genotypes. A comprehensive evaluation of turf performance by using the subordinate function values analysis indicated that the wild Dr5 exhibited superior characteristics including fast establishment， short canopy height， dark green leaf color， high uniformity， and the longest green period， demonstrating high lawnscape value. In contrast， wild Dr17 showed the poorest turf performance. Under consecutive two-year low-temperature stress， all genotypes showed significant declines in chlorophyll content and fluorescence parameters （Fv/Fm and PI_ABS）， but electrolyte leakage and malondialdehyde content exhibited varying degrees of increase. Notably， Dr5 demonstrated the lowest semilethal temperature， lower EL and MDA content， and higher chlorophyll content， Fv/Fm， and PIABS. These findings indicated that Dr5 had significantly lower oxidative damage to cell membrane， enhanced membrane stability， and superior photosynthetic performance under cold stress. Based on a comprehensive evaluation of cold tolerance using the subordinate function values analysis over two years， cold tolerance of 12 genotypes was ranked in descending order as follows： Dr5>Dr21>Dr1>Dr32>Dr2>Dr33>Dr30>Dr3>Dr4>Dr15>Dr11>Dr17. Dr5 exhibited the strongest cold resistance， and Dr17 had the weakest cold tolerance. Given its excellent turf quality and exceptional cold tolerance， Dr5 could be used as a superior germplasm for landscaping and a key candidate for breeding cold-tolerant dichondra cultivars. These findings also lay a foundation for further research into the low-temperature adaptation mechanism of different dichondra genotypes.

Key words: LTLow-temperature semilethal temperature, Photochemical efficiency, Dichondra repens, Turf performance, Cell membrane stability

摘要： 马蹄金（Dichondra repens）是一种旋花科的暖季型草坪地被植物，广泛应用于园林绿化、水土保持及果园生草，低温胁迫是限制其推广利用的主要因素。本试验以9份西南地区野生马蹄金、两份国审马蹄金新品种以及1份广泛使用的引进品种为材料，综合评价了12份马蹄金材料的田间坪用性状与低温适应能力。研究结果表明，12份马蹄金材料在叶面积、均一性、叶色、绿期长度、草层高度和成坪速度上存在显著差异。坪用性状隶属函数综合分析显示，野生材料Dr5具有成坪速度较快、草层低矮、叶色深绿、均一性高及绿期最长等优点，坪用景观价值较高，而Dr17坪用性能最差。在连续两年的田间低温胁迫下，12份马蹄金的叶绿素含量和叶绿素荧光参数（Fv/Fm和PI_ABS）显著下降，而电解质渗透率和丙二醛含量均呈现不同程度的增加趋势。但低温胁迫下Dr5具有最低的半致死温度，较低的电解质渗透率和丙二醛含量，同时维持了较高的叶绿素含量、Fv/Fm和PI_ABS，表现出显著低的细胞膜氧化伤害及良好的细胞膜稳定性与光合性能。采用两年耐寒性指标进行隶属函数法综合分析发现，12个马蹄金材料抗寒能力由强到弱依次为Dr5>Dr21>Dr1>Dr32>Dr2>Dr33>Dr30>Dr3>Dr4>Dr15>Dr11>Dr17，其中Dr5耐寒性最强，Dr17耐寒性最弱。Dr5兼具坪用性能好且耐寒性强的优点，可作为园林绿化应用的优选种质，为培育耐寒型暖季型马蹄金新品种提供了关键材料，也为进一步深入研究不同基因型马蹄金的低温适应机制奠定了基础。

关键词: 低温半致死温度, 光化学效率, 马蹄金, 坪用性能, 细胞膜稳定性