Effects of meteorlogical and soil factors on seed germination of Corethrodendron multijugum (Maxim.) B. H. Choi et H. Ohashi
Description
Five distinct counties were selected within Qinghai Province: Hualong County (HL), Huzhu County (HZ), Guide County (GD), Wulan County (WL), and Dulan County (DL).For each county, five categories of meteorological data spanning 30 consecutive years were selected for analysis: annual average temperature (AT), annual average land surface temperature(LST), annual average relative humidity(RH), annual cumulative sunshine duration(SD), and annual cumulative precipitation(CP).Soil samples were collected using the following steps[24]. Using a soil auger with an inner diameter of 3.5 cm, collect nine S-shaped soil cores at depths ranging from 0 to 20 cm as composite soil samples. In addition, each sampling point uses a circular knife to take an undisturbed soil and immediately weigh its wet weight for subsequent determination of soil moisture content. To prevent the influence of plant litter on soil properties, we strictly excluded any presence or residue of such debris during sampling. Soil samples were then passed through a 2 mm sieve to remove roots and stones. Subsequently, each soil sample was divided into three portions. One portion was stored at 4°C for analysis of inorganic nitrogen (ammonium nitrogen and nitrate nitrogen nitrogen) and available phosphorus. Another portion was air-dried indoors for determining soil physicochemical properties. Seed germination test of Corethrodendron multijugum (Maxim.) B. H. Choi et H. Ohashi was carried out in the laboratory in December, 2024. From each sampling point, 50 seeds were randomly selected from the seed bag and the process was repeated three times. First, the seeds were rinsed with distilled water, then disinfected with a 10% NaClO solution for 5 minutes. Afterwards, the seeds were rinsed again with distilled water for 2 minutes, and finally dried by blotting with filter paper. Moisten the filter paper with distilled water and lay it flat in a sterile 9-cm diameter petri dish. Distribute the seeds evenly on the filter paper, then added 7 ml of distilled water to each dish. A total of 45 petri dishes were obtained (15 sampling points × 3 replicates). The light incubator should be set to a cycle of 14 hours of illumination at 25°C, followed by 10 hours of darkness at 20°C, with a relative humidity of 60%. Subsequently, all Petri dishes were to be placed inside. The number of germinated seeds was recorded once every 24 hours, and new filter paper and distilled water were replaced. When no new seeds germinate for five consecutive days, the seed germination experiment was considered complete. The germination test lasted a total of 14 days. On the final day of the experiment, the plumule length (PL), and radicle length (RL) of 10 seedlings in each petri dish were recorded. If fewer than 10 seedlings were present, the plumule and radicle lengths of all seedlings were measured.