凋落物物理阻隔对格氏栲种子萌发及胚根生长的影响

为了探讨凋落物物理阻隔对格氏栲天然林自然更新状况的影响,通过模拟野外凋落物覆盖,设置格氏栲种子上层覆盖厚0 cm(CK)、2 cm(D2)、4 cm(D4)、6 cm(D6)、8 cm(D8)及种子下层铺垫厚2 cm(U2)、4 cm(U4)凋落物等7个处理,分析凋落物覆盖方式及厚度对格氏栲种子萌发及胚根生长的影响。结果表明:(1)凋落物覆盖方式及厚度对种子萌发进程存在显著影响。CK萌发持续时间最长,上层覆盖处理(D)次之,下层铺垫处理(U)的种子起始萌发时间显著滞后。(2)CK种子萌发率最高,其次D6处理发芽速度较快,发芽整齐;U处理较D处理的发芽率及发芽势均显著降低,且萌发抑制率显著增加。(3)D处理的种子胚根生长速度快,胚根长度大于CK;U处理的种子胚根生长速度呈先慢后快趋势。可见,凋落物是影响格氏栲种子萌发及胚根生长的重要因素,主要通过阻碍种子与土壤接触而抑制萌发,影响格氏栲林更新。

Effects of physical barrier of litter on the seed germination and radicle growth of Castanopsis kawakamii

In order to explore the effects of litter physical barrier on the natural regeneration of Castanopsis kawakamii forest, we set up seven treatments with 0 cm (CK), 2 cm (D2), 4 cm (D4), 6 cm (D6), 8 cm (D8) litter in the upper layer and 2 cm (U2), 4 cm (U4) litter in the lower layer of the seed by simulating litter cover in the field. The aim was to study the effects of litter cover and thickness on the seed germination and radicle growth of C. kawakamii. The results showed that: (1) litter cover and thickness had significant influences on the seed germination process. The CK had the longest seed germination duration, followed by D treatments (litter on the upper layer of the seed). The initial germination time of U treatments (litter on the lower layer of the seed) was significantly delayed. (2) the CK had the highest seed germination percentage. The seed germination of D6 treatment was relatively fast and evenness. The seed germination percentage and germination potential of U treatments were both significantly decreased compared with that of D treatments, and the germination inhibition rate was significantly increased. (3) the radicle growth of D treatments was relatively fast, and their radicle length was longer than those of CK. The radicle growth rate in the U treatments showed a slow trend followed by fast tendency. The results showed that forest litter was an important factor, which influenced the seed germination and radicle growth of C. kawakamii. It mainly inhibited seed germination by hindering the interaction between seed and soil, thus affected the C. kawakamii forest regeneration.