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研究生:卓娟秀
研究生(外文):CHO, CHUAN-HSIU
論文名稱:五種林木種子對乾旱的敏感性與微細構造
論文名稱(外文):Desiccation Sensitive and Ultrastructure of Five species of Tree seeds
指導教授:黃玲瓏黃玲瓏引用關係---
指導教授(外文):KUO-HUANG, LING LONG
學位類別:碩士
校院名稱:國立臺灣大學
系所名稱:植物學系研究所
學門:生命科學學門
學類:生物學類
論文種類:學術論文
論文出版年:1998
畢業學年度:86
語文別:中文
論文頁數:110
中文關鍵詞:異儲型種子含水率對乾燥敏感發芽率微細構造胚的主軸
外文關鍵詞:Recalcitrant seedmoisture contentDesiccation Sensitivygerminationultrastructureembryo axes
相關次數:
  • 被引用被引用:3
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中文摘要
本論文是以波羅蜜(Artocarpus heterophyllus Lam.)、大葉楠(Machilus japonica
var. kusanoi Hayata)、青剛櫟(Cyclobalanopsis glauca(Thunb.)Oerst.) 、長葉木
薑子(Litsea acuminata (Blume) Kurata)與銀合歡(Leucaeleucocephala Lam.)等台灣低
海拔不同生育地的林木種子為材料,觀察新鮮種 子外形、胚的主軸(embryo axes)的形
態與解剖特色及種子中不可溶儲藏物質的化學成份,並探討乾旱處理對種子存活力的影響
。此外,亦觀察五種種子 的胚軸、胚芽及胚根頂端分生組織之微細構造的差異及比較各
種胚的主軸受到乾燥處理後在微細構造上的變化。
由實驗結果顯示五種種子的體積以波羅蜜最大而銀合歡最小,然而此二種子胚的主軸
大小相似,其餘三種的胚軸較小;各胚軸在種子成熟採收時大多已 發育,但可見4∼6枚
初生葉包被在胚芽外,然而青剛櫟僅為一團尚未明顯分 化的細胞。大葉楠、青剛櫟及
長葉木薑子等種子的子葉及胚軸內均具有分泌細 胞或油細胞,波羅蜜的胚軸與子葉中含
有乳汁管,而單寧細胞則普遍存在於各 種子胚軸的皮層與表皮組織、初生葉及根帽組織
中。種子胚軸中不可溶性的儲藏物質,以澱粉粒、蛋白質體及油滴為主。波羅蜜、大葉楠
與長葉木薑子的胚軸基本組織細胞中可見澱粉體,而油滴則分布於 胚軸組織的細胞質中
以及胚芽與胚根分生組織細胞的邊緣。銀合歡胚的主軸細胞的邊緣與蛋白質體的外圍密佈
小油滴。除銀合歡外,各胚軸中較少見蛋白質體的存在。
成熟採收的五種種子的含水率以波羅蜜(61.03%)最高,而銀合歡(6.7%)最低;就
新鮮種子的發芽率而言,則分別為60%、95.04%、96%、93.33%、94%。經過氯化鋰飽
和鹽溶液乾燥處理後的種子,經萌發實驗的結果得知,波羅蜜、大葉楠、青剛櫟、長葉木
薑子各種子若分別失去其含水量的6%、7.5%、17%、35%,則發芽率急速降低;若儲存
於4℃的環境下,各種子保存活力的時間以銀合歡最長而波羅蜜最短。故而這些種子對乾燥
的敏感性,由強到 弱分別為波羅蜜、大葉楠、青剛櫟、長葉木薑子、銀合歡。
觀察各種子胚芽與胃根頂端分生組織細胞的微細構造,顯示此二部份的細胞質濃厚,
細胞核大而明顯,佔細胞空間的20∼30%;細胞質中液胞所佔的比例則依種類的不同而大小
不一。在粒線體、內質網、色素體等胞器發育狀況與 分布的觀察中,銀合歡的細胞質中少
見各種胞器,其餘四種則顯見各胞器的存 在與活動的跡象。
當種子受到乾旱產生水分逆境時,在種皮、子葉與胚的主軸外觀上出
現明顯的皺縮現象
,含水率也明顯下降。透過微細構造的觀察,胚芽分生組織細胞隨著含水
率的下降,出現液
胞癒合或液胞膜破裂,各胞器的形態與相對空間位置改變、細胞核與核仁
變形、原生質質離
與細胞邊緣出現小囊泡化等現象;在胚根的分生組織細胞內有類似的變化
但較不明顯,而根
帽部份的細胞則出現明顯的原生質離現象,細胞中液胞化的現象也較胚根
頂端分生組織明顯。
對乾燥敏感性較低的種子,通常其胚芽及胚根頂端分生組織細胞的細
胞質較濃厚,液胞
極小或沒有,細胞儲藏物以油滴與蛋白質體為主;隨著對乾燥敏感性的提
昇,胚主軸頂端分
生組織細胞的液胞化現象增加,各胞器亦呈相對程度的增加或出現活化狀
態,並與種子萌發
的第一發芽時間成正相關。本研究的五種種子中,對乾燥敏感性最強的波
羅蜜種子的胚芽與
胚根頂端分生組織細胞內具有高度液胞化的現象,與其他敏感性較弱的種
子間呈現顯著差異
;而就其他乾燥敏感性程度不同的種子與銀合歡種子比較,其液胞化程度
亦呈顯著差異,但
彼此間則差異不大。
Abstract Artocarpus heteroqhyllus Lam., Machilus
japonica var. kusanoi Hayata, Cyclobalanopsis glauca (Thunb.) Oerst, Litsea a
cuminata (Blume) Kurata and Leucaena leucocephala Lam. are five woody species
distrributed in the low forests of Taiwan. This thesis investigated their seed
morphology and the anatomical characteristics, including the composition of i
nsoluble storage materials, the ultrastructure of plumule and apex of radicle
of the embryo axes. Besides the effects of desiccation on the seed viability a
nd the ultrastructure of embryo axes were studied. The
results showed that Art
ocarpus has the biggest seed mass, however, the size of its embryo axes is sim
ilar to that of Leucaena. Among the five species the seed of Leucaena is the s
mallest one. With the exception of Cyclobalanopsis, all the other embryo axes
in matured seed are full-grown andgenerally with 4-6 primary leaves. In the c
otyledons and embryo axes of the seeds of Machilus, Cyclobalanopsis and Litsea
there are secretory mucilage or oil cells. The seeds of Artocarpus obviously
contain laticifers in the cotyledons and embryo axes. However, tannic cells ar
e ubiquitously distributed in the cortex and epidermis of embryo axes, primary
leaves and root caps of the seeds. The predominant
compositions of insoluble
storage materials in the seeds of these five species are starch grains, protei
n bodies and oil droplets. The starch grains are distributed in the ground tis
sue of embryo axes of Artocarpus , Machilus and Litsea.. The oil droplets are
located in the cytoplasm of the cells of embryo axes and in the marginal areas
of the cells of plumule and radicle apex. Nevertheless, in the seeds of Leuca
ena, the oil droplets are mostly observed around the proteins bodies in the pe
ripheryn of the cells in he embryo axes.The highest and lowest moisture conten
ts of mature seed are fong in Artocarpus (61.03%) and Leucaena (6.7%) respec
tively, and the rates of germination are 60% (Artocarpus ) , 95.04% (Machilus
), 96% (Cyclobalanopsis ), 93.33% (Listea) and 94% (Leucaena). When the seeds
were lost dehydrated 6% (Artocarpus ), 7.5% (Machilus), 17% (Cyclobalanopsis)
, 35% (Lacumunata) of their moisture contents by the saturated lithium chlorid
e (LiCl), the rate of germination decreased dramatically. Among the five woods
, the seed of Lacumunata are the most resistant to low temperature storage (4
0C) and seed of Artocarpus are more susceptable to low temperature treatment.
These results suggest that the degrees of desiccation susceptibility of these
seeds are Artocarpus, Machilus, Cyclobalanopsis, Litsea and
Leucaena. The ultr
astructural study on the seeds showed the cells of plumule and radicle apex ha
s dense cytoplasm, and a large nucleus occuping 20-30% of the cell volumn. The
size of vacuoles in the cytoplasm widely varies with the species. In the cyto
plasm of Leucaena, the mitochondria, endoplasmic reticulum and plastids are se
ldom observed, however, in other species these organelles are ubiquitous distr
ibuted and metabolic active. During the drought stress,
the seed coat, cotyle
don and embryo axes are obviously shrunk. The ultrastructural change in the ce
lls of plumule apical meristem are fusion or lysis of tonoplast, deformation o
f nucleus and nucleolus, shrinkage of protoplasm, and formation of small vesic
les in the cell periphery. A similar, but less significant change was observe
d in the radicle apex, however, the cells in the radicle showed dramatic plasm
olysis and vacuolation. In summary, the present study
suggested that the more
resistant to the desiccation a seed, the more densely of the cytoplasm in the
cells of apex of plumule and radicle. Besides, in the desiccation resistant se
eds the vacuoles are small or lack, and the predominant storage compounds are
oil droplets and protein bodies. The vacuolation of the apical meristematic ce
lls and the activity and the quantity of organelles in the cells of embryo axe
s are increased with the desiccation susceptibility of the seeds. In the seeds
of the five studied species, , highly vacuolation was only found in the plumu
le and radicle of Artocarpus seed, and the degree of vacuolation in the other
four species is not significantly different, but is highly associated with th
eir desiccation susceptibility. VII
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