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ワルナスビ(Solanum carolinense L.)の種子による牧草地への侵人過程に関する研究
https://doi.org/10.24514/00002131
https://doi.org/10.24514/000021315eaf5fc4-7d86-4988-ba0e-434f9c499c99
| 名前 / ファイル | ライセンス | アクション |
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ilgs_report_No7p51-93p.pdf (746.2 kB)
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| Item type | 紀要論文01 / Departmental Bulletin Original Article(1) | |||||
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| 公開日 | 2019-03-22 | |||||
| タイトル | ||||||
| タイトル | ワルナスビ(Solanum carolinense L.)の種子による牧草地への侵人過程に関する研究 | |||||
| タイトル | ||||||
| タイトル | Studies on the Invasion Processes of Horsenettle (Solanum carolinense L.) via Seeds in Pastures | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | Solanum carolinense L. | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | ワルナスビ | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | 種子 | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | 侵入 | |||||
| キーワード | ||||||
| 主題Scheme | Other | |||||
| 主題 | 耕種的防除 | |||||
| キーワード | ||||||
| 言語 | en | |||||
| 主題Scheme | Other | |||||
| 主題 | Solanum carolinense L. | |||||
| キーワード | ||||||
| 言語 | en | |||||
| 主題Scheme | Other | |||||
| 主題 | Horsenettle | |||||
| キーワード | ||||||
| 言語 | en | |||||
| 主題Scheme | Other | |||||
| 主題 | seed | |||||
| キーワード | ||||||
| 言語 | en | |||||
| 主題Scheme | Other | |||||
| 主題 | invasion | |||||
| キーワード | ||||||
| 言語 | en | |||||
| 主題Scheme | Other | |||||
| 主題 | cultural control | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| ID登録 | ||||||
| ID登録 | 10.24514/00002131 | |||||
| ID登録タイプ | JaLC | |||||
| 著者 |
西田, 智子
× 西田, 智子 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Horsenettle (Solanum caroljnense L.) is native to the Gulf States in the United States. It is a perennial weed that propagates by its seeds, roots and root cuttings. The plant has conspicuous spine-like prickles on the stems and leaves. It is also considered to be poisonous due to its solanine content. It is a troublesome weed in various types of crops such as corn, small grains and vegetables, as well as pastures in North America. Problems associates with this weed in pastures in Japan became noticeable in the 1970's, but occurrences of the weed were considered to have been restricted to small areas. However, it has become apparent that the area in which horsenettle can be found is expanding. It is difficult to control the weed with ordinary pasture management practices such as grazing and cutting. Some of herbicides are effective in controlling the weed, but they are not practical in terms of the cost or efficiency. Therefore, the most efficient means of avoiding the negative effect of horsenettle is to prevent the weed from invading and being established in new areas. The present study was conducted in order to elucidate the ways in which horsenettle invades pastures via seeds mixed into imported fodder crops and examine factors associated with seedling establishment. The presence of horsenettle in pastures in central Japan was assessed by surveying 24 pastures from 1993 - 1998. Twenty-five percent of the surveyed pastures were found to be infested with the weed. Horsenettle is considered to be a species of alien weeds whose source of invasion is seeds mixed into imported fodder crops. The supply of concentrate applied during the grazing season, however, was not significantly related to the presence of horsenettle. The annual mean temperature in infested pastures was significantly higher than that in non-infested pastures. The probability of the weed being present was significantly lower in pastures where the average monthly air temperature over the three of the coldest months of the year was below the freezing point. The effects of cattle digestion and of composting heat on the weed seed viability were investigated for the purposes of this study. Although the viability of horsenettle seeds ingested by cattle was significantly lower than that of non-ingested seeds, approximately 60% of the seeds that passed through the digestive tract of cattle remained viable. Furthermore, among the seeds estimated to be contained in excreta placed outdoors, 15% germinated and grew to come out. Composting heat was considered to be effective in reducing the viability of alien weed seeds, including horsenettle, if the manure was appropriately fermented and a temperature of 55℃ was maintained for 42 to 58 hours, or if a temperature of 60℃ was maintained for 10 to 17 hours. The temperature range for germination, accumulated effective temperature and the effects of temperature fluctuations on horsenettle seeds were also investigated. Base temperature (T_b) and accumulated effective temperature (θ) to germinate seeds treated with gibberellin were calculated by Garcia-Huidobro' s method. T_b was estimated to be approximately 15℃. Gompertz function adequately described the relationship betweenθand germination fraction (%). The germination percentage of seeds exposed to diurnal temperature fluctuation with an upper limit of 15 - 30℃ and amplitudes of 5 - 15℃ for 10 or 20 cycles was significantly higher than that of seeds incubated at a constant temperature of 30℃. The seeds that were incubated at lower temperatures needed more cycles to increase their germination percentage. Horsenettle seeds appeared to respond to temperature fluctuation even below T_b. The effect of sowing dates and competition with orchardgrass (Dactylis glomerata L.) on emergence and growth of horsenettle seedlings was investigated. The sowings were conducted at approximately monthly intervals from April through August in 1996 under conditions with and without orchardgrass sown in April 1996 (Hereafter, the former treatment will be referred as 'OG' and the latter as 'BARE'.). With the exception of the July sowing, the cumulative percentages of horsenettle emergence approximately two months after sowing in BARE were 80 % or higher for all sowings. In OG, the emergence percentages for the April and May sowings were higher than 45 %, while the percentages for the remaining sowings were nearly zero. Most of the seedlings for April through June sowings in BARE re-sprouted following the winter in May 1997. In OG, almost none of the shoots from any of the sowings were observed to have re-sprouted. The trend of horsenettle growth in September agreed well with that of the re-sprouted shoot number in May of the next year. Experiments were also conducted to elucidate the possibility of seedling establishment for horsenettle during pasture renovation. Horsenettle seeds were sown on September 4 (SEP4), September 26 (SEP26) and October 15 (OCT15) in 2001 under conditions with and without orchardgrass sown on the same dates as the weed seeds except for OCT15 (Hereafter, the former treatment will be referred as 'OG' and the latter as 'BARE'.). For OCT15, the grass seeds were sown on September 26. The percentage of horsenettle that survived the winter was high for SEP4-BARE at 73%, but the percentages were below 10% for all other treatments. The freezing tolerance of horsenettle was investigated using seedlings sown on August 13 (AUG) and September 4 (SEP). The seedlings sown on each of these days were exposed to a temperature of-4℃ for a period of 3, 6, 9 and 12 hours, respectively. The viability of the seedlings for AUG was not reduced even after 12 hours of exposure, whereas the viability of those for SEP decreased as the exposure time increased. A 95% confidence interval for the exposure time at which viability was reduced to 10% was estimated to be 12 to 20 hours for the seedlings in SEP. Based on these findings, it was believed that the possibility of seedling establishment for horsenettle during pasture renovation would be low in the northern Kanto region and colder areas if the sown grasses became well established. In order to prevent horsenettle invasion and establishment, the following were suggested based on the results of the study. 1) Manure should be treated adequately to raise its maximum temperature above approximately 60℃. 2) When pastures are renovated, sowing should be timed to enable the sown grasses to be well established. To avoid horsenettle establishment, late sowing is considered to be better for pastures where autumn sowing is appropriate. 3) Empty gaps in pastures should be minimized with adequate pasture management practices, such as over-sowing. 4) Dissemination of information on horsenettle to relevant people is important to prevent horsenettle invasion and allows them to take appropriate countermeasures before the weed becomes fully established. | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | ワルナスビは米国メキシコ湾岸州原産の多年生雑草で, 茎葉に鋭いトゲを持ち家畜に有害なソラニンを含む。種子と根, 根片で繁殖し, 北米では, トウモロコシ, ダイズあるいは牧草地等の強害雑草である。日本では, 1970年代に牧草地の雑草として問題になったが, 被害は一部地域に限定されると考えられていた。しかし, 現在その分布範囲は広がっている。ワルナスビは, 一般的な草地管理では, 防除が困難であり, 安価で効率的な除草剤も現在のところ登録されていない。従って, 新たな侵入・定着を阻止することが最も効率的な防除法である。このような背景を踏まえ, ワルナスビの種子による侵入経路の解明と, 実生の定着に関する要因を明らかにするために本研究を実施した。1) 日本中央部の牧草地におけるワルナスビの分布 新潟県, 長野県および栃木県を中心とした日本中央部の24の牧草地で, 1993～1998年にかけて, ワルナスビの有無を調査した。ワルナスビの発生が観察された調査地は約1/4であった。ワルナスビの侵入源は, 輸入濃厚飼料に混入した種子と推測されるので, 濃厚飼料給与の有無等の管理方法とワルナスビの発生との関係を調べたが, 有意な関係は認められなかった。一方, ワルナスビが存在した調査地の年平均気温は, ワルナスビが存在しなかった調査地の年平均気温よりも有意に高く, また, 最寒3ヶ月の月平均気温が永点下になる調査地では, そうでない調査地に比べてワルナスビの発生する確率が有意に低かった。2)輸入濃厚飼料を採食した牛を経由したワルナスビの侵入 牛に採食されたワルナスビ種子は, 糞中から83%が回収され, その内76%は生存していた。また, ワルナスビ種子を採食した牛の糞を戸外に置くと, 中に含まれると推定される種子の約15%が出芽した。堆厩肥中に埋設されたワルナスビを含む15種類の雑草種子は, 堆厩肥の最高温度が約60℃以上に上昇すると発芽力を失った。また, ワルナスビ種子よりも熱耐性のあるイチビ種子の死滅率が90%になる時間の95%信頼区間は, 55℃では42-58時間, 60℃では10-17時間と計算された。3) ワルナスビ種子の発芽に及ぼす温度の影響 ジベレリン処理をしたワルナスビ種子を供試し, 発芽最低温度, および有効積算温度と発芽率との関係を調査した。発芽最低温度は約15℃と推定され, 有効積算温度と累積発芽率との関係はゴンペルツ曲線でよく表された。また, ワルナスビ種子を温度や変温幅および回数を変えた変温条件に曝し, 発芽率を調査した結果, 発芽最低温度よりも低い15/10℃の変温条件でも暴露回数が多くなれば発芽率が向上した。4) ワルナスビ実生の出芽特性 4～8月にワルナスビ種子を裸地条件とオーチャードグラス(OG) との競合がある条件で1ヶ月おきに播種した結果, 播種後約2ヶ月間の累積出芽率は, 裸地区では, 7月播種区を除き約80%以上と非常に高かった。また, 裸地条件の4～6月播種区では出芽した個体のほとんど全てが越冬した。しかし, OGとの競合条件下では, OGの草冠が形成された6月播種区以降は, ほとんど出芽せず, また, 4および5月播種区も含めて, 播種翌年に再萌芽した個体はほとんど観察されなかった。また, 播種翌年5月の萌芽数は, 播種当年9月のワルナスビの生育量の傾向と良く一致した。5) ワルナスビ実性の越冬性および耐凍性 9月上, 下旬および10月中旬に, 裸地およびOGとの競合がある条件で, ワルナスビ種子を播種した。裸地条件で, 9月上旬に播種したワルナスビは約73%が越冬したが, それ以外の区の越冬率は10%以下であった。ワルナスビの播種数に対する播種翌年6月の生存個体割合は, 9月上旬播種区が最も高かった。8 月および9 月に播種したワルナスビ実生を当年12月に堀上げ, -4℃で3～12時間処理した結果, 8月播種のワルナスビは, 12時間処理でも無処理の場合とほぼ同程度の生存率を保った。一方9月播種のワルナスビは処理時間の経過とともに, 生存率が低下し, 回帰分析の結果, 生存率が10%となる処理時間の95%信頼区間は12-20時間と計算された。以上の結果から, ワルナスビの新たな侵入・定着を防止するために次のことを提言する。1) 堆厩肥は最高温度が約60℃以上となるよう, 適切に発酵させる。2) 草地更新は, 播種牧草の定着を確保するため, 播種適期に行う。また, 秋播きを行う地域では, ワルナスビ実生の定着を避けるためには, 適期の後半に播種することが望ましい。3) 牧草地内の裸地を最小限に保つよう, 追播技術もワルナスビの定着を防ぐために有効である。4) 牧草地の強害雑草として古くから認識されているエゾノギシギシに比較して, ワルナスビの分布域は現在のところ小さい。しかし, 前者については防除技術が一応の完成をみているのに対して, ワルナスビが蔓延した場合には更新以外に有効な防除手段がない。また, 日本における潜在的な分布可能域は北海道を含めかなり広いと考えられるため, 蔓延を未然に防ぐための関係者への情報の伝達が重要である。 | |||||
| 書誌情報 |
畜産草地研究所研究報告 en : Bulletin of National Institute of Livestock and Grassland Science 巻 7, p. 51-93, 発行日 2007-03-16 |
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| 出版者 | ||||||
| 出版者 | 独立行政法人 農業・食品産業技術総合研究機構 | |||||
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| 収録物識別子タイプ | ISSN | |||||
| 収録物識別子 | 1347-0825 | |||||
| DOI | ||||||
| 関連タイプ | isIdenticalTo | |||||
| 識別子タイプ | DOI | |||||
| 関連識別子 | 10.24514/00002131 | |||||
| 著者版フラグ | ||||||
| 出版タイプ | VoR | |||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||
