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
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.
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维普
