森林立地55(1), 2735 2013

Jpn J For Environ 55 (1), 27-35, 2013

 

南伊豆での露地栽培試験及び実験的手法による

フタバガキ科種の低温感受性の評価

 

昭一1下健1

1学院学生科学研究科

 

フタバガキ科樹分布を規する温にする感受性を,場に植栽した苗木の秋からにかけてのの光合成機能低下と茎の形成層壊死の経時化を調価した。Hopea odorataShorea roxburghiiShorea multiflora3種を供試した。光化学系II の最大量子収(Fv/Fm) は,いずれの種も,日最低気温が10℃以下,低地温(深さ10cm)15℃以下,日中(1013)の平均気温が20℃以下の日が連続するようになってから低下が明瞭になったが,S. multifloraの低下が他の2種に比べ大きかった。葉または根を低温処理する実験によって,気温の低下に伴うFv/Fmの低下には日中の気温低下の影響が大きいことが示唆された。S. multifloraの茎の形成層は,日最低気温が5℃以下になることが多くなった12月に半数の供試苗で,-0.3℃を観測した1月に全ての供試苗で壊死した。一方,H. odorataS. roxburghiiの茎の形成層は,日最低気温-2.4℃を観測した2月でも半数の供試苗で壊死せず,3月になってすべての供試苗で壊死した。茎に比べて,葉はより高い低温感受性を示すこと,他の2種に比べて,天然分布の北限の緯度が低いS. multifloraの低温感受性が高いことが明らかになった。

キーワード: フタバガキ科,温感受性,クロロフィル蛍光,形成層の壊死

 

Shoichi Ito and Takeshi Tange : Evaluation of chilling sensitivity of three species of Dipterocarpaceae by experi­mental methods and planting trial in southern part of Izu Peninsula, Japan. Japanese Journal of Forest Environ­ment 55:27-35, 2013.

In order to evaluate the chilling sensitivity of Diperocarpaceae species, we observed decline in photosynthetic activity and necrosis of vascular cambium of Hopea odorata, Shorea roxburghii and Shorea multiflora seedlings planted in south­ern part of Izu Peninsula from autumn to winter. After a series of days whose daily minimum temperature, daily minimum soil temperature (10cm in depth) and mean temperature of mid-day (10:00-13:00) were lower than 10,15 and 20 respectively, the maximum quantum efficiency of photosystem II (Fv/Fm) of each species showed apparent decline. The decline in S. multiflora was the largest among the three species. By the low temperature treatment for leaves or roots, it was suggested that the low temperature of mid-day caused the decline. Necrosis of vascular cambium of stem of S. multi­flora was observed on a half of the seedlings in December and on the all ones in January, when -0.3 of the daily mini­mum temperature was observed. The necrosis of H. odorata and S. roxburghii was observed on half of the seedlings in February when -2.4 of the daily minimum temperature was observed, and on all ones in March. It was revealed that the leaves showed higher chilling sensitivity than stems and that S. multiflora whose natural distribution was limited in lower latitude area showed higher chilling sensitivity than H. odorata and S. roxburghii.
Keywords: Dipterocarpaceae, chilling sensitivity, chlorophyll fluorescence, necrosis of vascular cambium


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