沙拐枣属4种植物同地栽培开花物候与生殖特性比较

Comparison of Flowering Phenology and Reproductive Traits of Four Species of Calligonum L.(Polygonaceae) under Ex-situ Conservation at the Turpan Eremophytes Botanical Garden in Xinjiang,China

选取吐鲁番沙漠植物园同地栽培的沙拐枣属(Calligonum L.)4种植物,在群体、个体、枝条、同化枝和单花5个水平上,2007—2009年连续进行开花物候和生殖特性研究。主要结论如下:①4a中4种沙拐枣的各项开花物候参数相似,2010年各项物候参数明显推迟,4月中旬的温度是影响开花时间的主要因素。②在个体和群体水平上,泡果沙拐枣(C.calliphysa)和红皮沙拐枣(C.rubicundum)相似,表现为"集中开花模式",花期重叠指数较高,达79.99%～100%,密刺沙拐枣(C.densum)和艾比湖沙拐枣(C.ebinuricum)相似,表现为"持续开花模式",花期重叠指数较高,为51.79%～79.82%,4个种的共有重叠期较短。③在枝条水平上,泡果沙拐枣和红皮沙拐枣开花物候特征也表现相似,为开放集中,开花振幅高;密刺沙拐枣和艾比湖沙拐枣表现相似,为开放时间长,开花振幅低。④在同化枝水平上,开花数、持续时间和同化枝长度在种间和年际间均有不同程度的差异,同化枝水平的始花位置种间也具有差异,表现为泡果沙拐枣、红皮沙拐枣、密刺沙拐枣始花位置主要集中在第2、3关节,艾比湖沙拐枣通常在第4关节。⑤在单花水平上,泡果沙拐枣、红皮沙拐枣、密刺沙拐枣、艾比湖沙拐枣的单花开放持续时间分别为(9.14±0.26)h、(12.95±1.07)h、(10.69±1.75)h、(22.40±1.92)h。⑥在同化枝水平上,4种沙拐枣开花高峰期的坐果率较高,开花数目与坐果数显著正相关;坐果数和开花位置有一定的关系,表现为着生花多的关节坐果数也高,其中,泡果沙拐枣的花和果主要集中在第2、3、4关节,红皮沙拐枣集中在第3、4、5关节,密刺沙拐枣集中在第2、3、4、5关节,艾比湖沙拐枣集中在第4、5、6关节。

Flowering phenology is considered as an important fitness factor because it plays a crucial role in reproductive success. Our aim is to investigate the flowering phenology of four species of Calligonum L., an important windbreak and sand-fixing shrub in Northwestern China, to know which factor is predominant in causing the differences among species and years, and to understand its reproductive features. We marked four species from four sections of Calligonum （C. calliphysa from C. calliphysa, C. rubicundum from Sect. Pterococcus, C. densum from Sect. Calligonum and C. ebinuricum from Sect. Medusae） in Tur- pan Eremophyte Botanical Garden. We observed the flowering phenology at five levels （population, individ- ual, branch, branchlet and single flower） for four years （2007-2010）. The main results were： （1） The phenology parameters in the four years were similar for the four species of Calligonum L. The phenology parameters of the four species delayed in 2010, and the temperature in mid-April was the main factor that had a significant effect on the time of flowering. （2） At population and individual levels, the flowering phe- nology characteristics of C. calliphysa and C. rubicundum were similar, exhibiting a ＂mass-flowering＂ pattern, and their overlapping percentage of flowering stage was 79.99 %- 100 % ; the flowering phenology characteristics of C. densum and C. ebinuricum were also similar, exhibiting an ＂extended-flowering＂ pattern, and their overlapping percentage was 51.79 %- 79.82 % ; the overlapping percentage of flowering stage of the four species were less than 25%. （3） At branch level, the flowering phenology characteristics of C. calliphysa and C. rubicundum were similar, exhibiting a ＂mass-flowering＂ pattern and a large flow- ering amplitude; the flowering phenology characteristics of C. densum and C. ebinuricum were also simi- lar, exhibiting a relatively long flowering time and a relatively little flowering amplitude. （4） At branchlet level, the flowering numbers, flowering duration and assimilation twig lengths of the four species showed differences among species and years; the first flowers of the four species were located at different joint of the branchlet： the first flowers of C. calliphysa, C. rubicundum and C. densum were located at No. 2 and No. 3 joints of the branchlet, and the first flower of C. ebinuricum was mainly located at No. 4 joints of the branchlet. （5） At single flower level, the flowering duration of a single flower of C. calliphysa , C. rubicundum , C. densum and C. ebinuricum were （9.14±0.26）h, （12.95±1.07）h, （10.69±1.75）h and （22.40 v1.92）h, respectively. （6） A significantly positive correlation exists between daily flowering number and fruit setting number, and the joints with more flowers have larger fruit setting number; The flowers and fruits of C. calliphysa were mainly located at on Nos. 2, 3, 4 joints, that of C. rubicundum were mainly located at Nos. 3, 4, 5 joints, that of C. densum were mainly located at Nos. 2, 3, 4, 5 joints, that of C. ebinuricum were mainly located at Nos. 4, 5, 6 joints.