光度、溫度和孢子撒播密度對台灣原生鐵線蕨屬 光度、溫度和孢子撒播密度對台灣原生鐵線蕨屬植物繁殖與生長之影響

Effect of Irradiance, Temperature, and Spore Sowing Density on Propagation and Growth in Adiantum Species Native to Taiwan

柯佳妏(Chia-Wen Ko)

指導教授 ： 葉德銘

國立臺灣大學/生物資源暨農學院/園藝學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02699

摘要

鐵線蕨屬(Adiantum)的蕨類廣受民眾喜愛，但是市面上本土自有品種少見。為生產大量原地適用的鐵線蕨屬植物，本論文以台灣原生鐵線蕨屬：毛葉鐵線蕨、半月鐵線蕨、鐵線蕨、翅柄鐵線蕨為試驗材料，主要探討在不同光度、溫度和孢子撒播密度下對鐵線蕨屬之孢子發芽、配子體發育及孢子體生長之影響。
用日光燈管數及燈管距離植株高度以調整光度，藉以瞭解培養光度0、30、60、90、120 μmol•m-2•s-1對鐵線蕨屬的孢子發芽和配子體發育之影響，栽培溫度27±3 ℃，每日光照12小時。在光度30 μmol•m-2•s-1下，皆適合毛葉鐵線蕨、鐵線蕨和翅柄鐵線蕨孢子發芽，發芽率分別可達70%、88%、80%以上，其中鐵線蕨具有暗發芽現象；在光度120 μmol•m-2•s-1下適合半月鐵線蕨孢子發芽，發芽率為56%。在光度30 μmol•m-2•s-1下皆適合毛葉鐵線蕨、鐵線蕨、半月鐵線蕨和翅柄鐵線蕨配子體發育，分別在孢子撒播後8週、9週、16週、16週長出第一片幼孢子葉。當光度超過30μmol•m-2•s-1，會導致4種蕨類孢子發芽遲緩、發芽率降低、配子體發育遲緩。但半月鐵線蕨孢子發芽適合光度為120μmol•m-2•s-1。
試驗材料培養在日/夜溫30/25、25/20、20/15或15/13 ℃的自然照明室，遮蔭61%，平均每日正午光強度為197 μmol•m-2•s-1。毛葉鐵線蕨、鐵線蕨、翅柄鐵線蕨孢子在30/25℃適合孢子發芽，發芽率分別可達79%、85%、86%；25/20℃適合半月鐵線蕨孢子發芽，發芽率為81%。在30/25℃下，毛葉鐵線蕨、半月鐵線蕨、鐵線蕨、翅柄鐵線蕨分別在孢子撒播後9週、7週、10週、12週長出第一片孢子葉。當溫度低於30/25℃，會導致4種蕨類孢子發芽遲緩、發芽率降低、配子體發育遲緩。但半月鐵線蕨當溫度超過或低於25/20℃會導致孢子發芽延遲以及孢子發芽率下降。
毛葉鐵線蕨和半月鐵線蕨行無配生殖，長出幼孢子體所需時間較其餘兩種行有性生殖的蕨類短。
改變孢子懸浮液之體積以獲致不同撒播密度，藉以瞭解撒播密度每cm2約63、39、31、25和21個孢子對臺灣原生鐵線蕨的孢子萌發和配子體生長之影響。孢子撒播密度對鐵線蕨孢子發芽無影響，撒播後4週平均發芽率皆可達82.42 %。孢子撒播後10週，鐵線蕨孢子撒播密度為每cm2約63個孢子時，不論穴格有無受到藻類或真菌污染皆可有一定量的孢子體形成。5種孢子撒播密度皆以兩性配子體發育為主；無性配子體隨著撒播密度增加而減少的趨勢；只有低密度的每cm2約21 顆孢子時無觀察到雄配子體；只有撒播密度為每cm2約63個孢子無觀察到雌配子體。配子體長度及寬度以無性及雄配子體較小，雌配子體次之，兩性配子體較大。
鐵線蕨和毛葉鐵線蕨幼孢子體培養在溫室內遮光0%、31%、55%、82%或88%下13個月後，調查其生長。鐵線蕨在遮光82%下有最大淨光合作用7.22 μmol•m-2•s-1。毛葉鐵線蕨在遮光88%下有最大淨光合作用5.4 μmol•m-2•s-1。兩種蕨類皆隨著光度增加，植株的鮮重、乾重下降，葉面積、最大葉長度、小羽葉數、小羽葉面積減少，小羽葉厚度無顯著差異，氣孔數、葉綠素計讀值下降；鐵線蕨的葉片數無顯著差異，孕性葉減少；毛葉鐵線的葉片數、孕性葉增加。2種蕨類在遮光0%和31%下，葉色偏黃且葉緣褐化。鐵線蕨和毛葉鐵線蕨在溫室內遮光82-88%生長良好。
5種遮光生長的鐵線蕨和毛葉鐵線蕨植株，擺設於室內低光3個月後，調查室內觀賞品質。鐵線蕨在遮光55%和88%下的光合作用和光補償點最小，且在遮光55%和88%栽培之室內觀賞品質最佳；毛葉鐵線蕨在中等遮光下的植株移入室內後會有大量葉片枯萎，但不影響新葉形成，在遮光31%和55%栽培之室內觀賞品質最佳。

關鍵字

鐵線蕨屬 ； 孢子發芽 ； 配子體發育 ； 孢子體生長

並列摘要

Adiantum is one of the most popular ferns worldwide. However, native Adiantum species are rare seen in the market due to the lack of information on propagation and production. Thus, the objectives of this thesis were to study the effects of irradiance, temperature, spore sowing density on spore germination, and gametophyte and sporophyte growth and development of several Adiantum species native to Taiwan.

Effects of various irradiance levels (0, 30, 60, 90, 120 μmol•m-2•s-1 photosynthetic photon flux, PPF) on spore germination and gametophyte development were determined at 27±3ºC under a 12-hour photoperiod provided from fluorescent lamps. Spores of A. hispidulum, A. capillus-veneris and A. soboliferun germinated well under 30 μmol•m-2•s-1 PPF, with 70%, 88%, and 80% germination rate, respectively. Spores of A. capillus-veneris could germinate in the dark conditions. In contrast, spores of A. philippense had a higher germination rate (56%) under 120 μmol•m-2•s-1 PPF condition. A. hispidulum, A. capillus-veneris, A. philippense and A. soboliferun produced the first frond after spore sowing for 8, 9, 16, and 16 weeks, respectively under 30 μmol•m-2•s-1, while higher irradiances (> 30 μmol•m-2•s-1) resulted in lower germination rate, and slower germination and gametophyte development.

Effects of day/night temperature of 30/25, 25/20, 20/15 or 15/13 ℃ on spore germination were studied under greenhouse conditions with an average noon PPF of 197 μmol•m-2•s-1. Spore germination rates at 30/25 ℃ of A. hispidulum, A. capillus-veneris, and A. soboliferun were 79%, 85%, 86%, respectively, higher than those at lower at temperature. In contrast, the highest spore germination (81%) of A. philippense was observed at 25/20 ℃. Under 30/25 ℃ conditions, A. hispidulum, A. capillus-veneris, and A. soboliferun produced the first frond after spore sowing for 9, 7, 10, 12 weeks, respectively. Lower temperature (< 30/25 ℃) resulted in slower and lower spores germination, and stunt gametophyte growth.

A. hispidulum and A. philippense exhibited apogamy, and thus reached sporophytic growth earlier than A. capillus-veneris and A. soboliferun which had a bisexual propagation.

Spore suspension was prepared with 63, 39, 31, 25, and 21 spores per cm2 to determine the effects of spore sowing density on spore germination and gametophyte growth. The germination was carried out in a growth room at 25±2ºC and 30μmol•m-2•s-1 PPF under a 12-hour photoperiod. All spores of the tested ferns germinated 4 weeks after sowing with an average of 82.4% germination rate, regardless of sowing density. Hermaphroditic gametophytes were majoly seen in all sowing density treatments. The number of asexual gametophytes decreased as the spore sowing density increased. No male gametophytes was observed with the low sowing density (21 spores per cm2). While no female gametophytes was observed with the high density treatment (63 spores per cm2). Hermaphroditic gametophytes had the largest size, followed by female gametophytes, and than asexual and male gametophytes.

Shading would affect the plant growth of A. capillus-veneris and A. hispidulum.Effect of 0%, 31%, 55%, 82%, or 88% shade in a greenhouse were studied on growth and photosynthesis. A. capillus-veneris veneris had the highest net photosynthetic rate of 7.22 μmol•m-2•s-1 with 82% shade. A. hispidulum had the highest net photosynthetic rate of 5.4 μmol•m-2•s-1 under 88% shading.

For both ferns, plant fresh and dry weights, frond area, stomatal number, and SPAD-502 values decreased as irradiance increased. A. capillus-veneris produced fewer, but A. hispidulum had more, fronds with sorias irradiance increased. Yellow and necrotic fronds were observed in both ferns under 0% or 30% shading conditions.

Interior performance was evaluated in plants grown under various shading in a greenhouse followed by 3-month indoor conditions. A. capillus-veneris had the lowest light compensation point and had the best interior performance when grown previously under 55% or 88% shading conditions. A. hispidulum performed best when grown under 31% or 55% shadings.

並列關鍵字

Adiantum ； spore germination ； gametophyte development ； sporophyte growth

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