海岸林孔隙對海檬果更新之影響

EFFECTS OF LITTORAL FOREST GAPS ON REFORESTATION WITH CERBERA MANGHAS

王經文(Ching-Wen Wang)；洪淑婷(Shu-Ting Hong)；陳財輝(Tsai-Huei Chen)；廖天賜(Tien-Szu Liao)；陳宜敏(Yi-Min Chen)；陳忠義(Chung-I Chen)；黃士元(Shin-Yuan Huang)；陳奐存(Huan-Tsun Chen)

海檬果 ； 葉綠素螢光 ； 孔隙 ； 最大淨光合速率 ； Cerbera manghas ； Chlorophyll fluorescence ； Gap ； The maximum photosynthetic rate

中華林學季刊

51卷1期（2018 / 03 / 01）

69 - 85

繁體中文

本研究嘗試直播海檬果(Cerbera manghas)於臺灣新竹縣新豐段海岸林現場，探討其幼苗對不同孔隙環境之適應性，並以苗圃為對照，作為本地區林分更新作業參考。現場選定大孔隙、小孔隙及林下三種不同孔隙大小林分，苗圃則設置相對光度100 %、40 %、20 %及5 %四種光度環境。就形態表現，苗圃苗之地徑隨相對光度增加而增加，然現場苗則無此趨勢且生長量皆遠低於苗圃者，明顯生長表現不佳；就生理方面，苗圃者在相對光度100 %有顯著較高之最大淨光合速率；而現場者在大孔隙下則無，加上其葉綠素螢光日變化之Fv'/Fm'及ΦPSII有較高的變動幅度，Fv/Fm也顯著較低，顯示其調適速度較慢，推測海檬果在兩地全光環境生長的差異，係受生長之立地條件的影響，因此就海檬果於海岸林林下更新的考量評估，應較適合直播於相對光度約40%至20%的林分小孔隙或林下處，較能提高造林成功率。

To offer the reference for stand regeneration in the littoral forest area in Xinfeng section, Hsinchu County, Taiwan, the main goal of this study is trying to compare the seedling growth of Cerbera manghas between direct seeding in the field and those growing in nursery under different light conditions. We classified three gap types as large gap, small gap and understory in the field, and treated using four light intensity treatments of 100 %, 40 %, 20 % and 5 % of full sunlight in the nursery. As for the morphological results, the basal diameter of the nursery seedlings increased with increasing relative light intensity. However, seedlings in the field did not reflect the fluctuation and the growth increments were lower than the nursery seedlings. As for the physiological results, the seedlings in the 100% treatment represented the highest maximum photosynthetic rate (A_(max)) in the nursery; however seedlings in the large gap had no significantly higher A_(max) than the other gap types in the field. In addition, the seedlings in the large gap showed the higher variation of Fv'/Fm' and ΦPSII, and significantly lower Fv/Fm for diurnal variation of chlorophyll fluorescence. This indicated that seedlings in the large gap have slower regulating capability than the others. Hence, we suppose although C. manghas showed good adaptability in full light environment, their growth still restricted or even stressed when growing in full light with abominable environment. As a summary, when assessing and considering seeding regeneration in littoral forest understory with C. manghas, smaller gap, around 40 to 20% relative light intensity is better and have more promotive success of afforestation.