在(zai)中(zhong)國(guo),珙(gong)桐(tong)分布廣泛。“珙(gong)桐(tong)之鄉(xiang)”的(de)珙(gong)縣王(wang)家鎮分布著全國(guo)數(shu)量眾多的(de)珙(gong)桐(tong)。其它分布于陜西東(dong)(dong)(dong)南(nan)(nan)部鎮坪、嵐皋(gao),湖(hu)北(bei)(bei)(bei)西部至(zhi)西南(nan)(nan)部神農架、興山(shan)(shan)、巴東(dong)(dong)(dong)、長陽、利(li)川(chuan)(chuan)(chuan)、恩(en)施、鶴峰、五(wu)峰,湖(hu)南(nan)(nan)西北(bei)(bei)(bei)部桑(sang)植、大(da)庸(yong)、慈利(li)、石門、永(yong)順(shun),貴(gui)州東(dong)(dong)(dong)北(bei)(bei)(bei)部至(zhi)西北(bei)(bei)(bei)部松桃、梵凈(jing)山(shan)(shan)、道真、綏陽、畢節(jie)、納雍,四川(chuan)(chuan)(chuan)東(dong)(dong)(dong)部巫山(shan)(shan),北(bei)(bei)(bei)部平武、青川(chuan)(chuan)(chuan),西部至(zhi)南(nan)(nan)部汶川(chuan)(chuan)(chuan)、灌縣、彭縣、寶興、天(tian)全、峨(e)眉(mei)、馬邊、峨(e)邊、美姑、雷波、筠連,重(zhong)慶南(nan)(nan)部南(nan)(nan)川(chuan)(chuan)(chuan),云南(nan)(nan)東(dong)(dong)(dong)北(bei)(bei)(bei)部巧家、綏江(jiang)、永(yong)善、大(da)關、彝(yi)良、威信(xin)、鎮雄(xiong)、昭通,廣東(dong)(dong)(dong)省懷集縣詩洞鎮六龍的(de)深山(shan)(shan)野(ye)嶺里等地。常(chang)混生于海(hai)拔(ba)1250~2200米(mi)的(de)闊(kuo)葉林(lin)中(zhong),偶有小(xiao)片純(chun)林(lin)。在(zai)四川(chuan)(chuan)(chuan)省滎經縣,也發現(xian)(xian)了(le)數(shu)量巨大(da)的(de)珙(gong)桐(tong)林(lin),達10萬(wan)畝之多。在(zai)桑(sang)植縣天(tian)平山(shan)(shan)海(hai)拔(ba)700米(mi)處,還發現(xian)(xian)了(le)上千畝的(de)珙(gong)桐(tong)純(chun)林(lin),是目前發現(xian)(xian)的(de)珙(gong)桐(tong)最集中(zhong)的(de)地方。
落(luo)葉喬木(mu),高15-20米(mi)(mi),稀達(da)25米(mi)(mi);胸高直徑約1米(mi)(mi);樹皮(pi)深(shen)灰(hui)色(se)(se)(se)(se)或(huo)深(shen)褐色(se)(se)(se)(se),常(chang)(chang)裂(lie)成不規則(ze)的(de)(de)(de)薄片而(er)脫(tuo)落(luo)。幼枝(zhi)(zhi)(zhi)圓柱(zhu)形(xing)(xing),當(dang)年生枝(zhi)(zhi)(zhi)紫(zi)綠(lv)(lv)(lv)色(se)(se)(se)(se),無(wu)毛(mao)(mao)(mao),多(duo)年生枝(zhi)(zhi)(zhi)深(shen)褐色(se)(se)(se)(se)或(huo)深(shen)灰(hui)色(se)(se)(se)(se);冬芽錐形(xing)(xing),具(ju)4-5對卵形(xing)(xing)鱗片,常(chang)(chang)成覆瓦(wa)狀排列。葉紙(zhi)質(zhi)(zhi),互生,無(wu)托葉,常(chang)(chang)密集于幼枝(zhi)(zhi)(zhi)頂(ding)端(duan),闊(kuo)卵形(xing)(xing)或(huo)近圓形(xing)(xing),常(chang)(chang)長(chang)9-15厘(li)米(mi)(mi),寬(kuan)(kuan)7-12厘(li)米(mi)(mi),頂(ding)端(duan)急(ji)尖或(huo)短(duan)急(ji)尖,具(ju)微彎曲的(de)(de)(de)尖頭,基(ji)部心臟形(xing)(xing)或(huo)深(shen)心臟形(xing)(xing),邊緣有三角形(xing)(xing)而(er)尖端(duan)銳(rui)尖的(de)(de)(de)粗(cu)(cu)鋸齒,上(shang)(shang)面(mian)(mian)亮綠(lv)(lv)(lv)色(se)(se)(se)(se),初被(bei)很(hen)稀疏(shu)的(de)(de)(de)長(chang)柔毛(mao)(mao)(mao),漸老時(shi)無(wu)毛(mao)(mao)(mao),下(xia)(xia)(xia)面(mian)(mian)密被(bei)淡(dan)黃色(se)(se)(se)(se)或(huo)淡(dan)白色(se)(se)(se)(se)絲狀粗(cu)(cu)毛(mao)(mao)(mao),中脈(mo)(mo)和8-9對側脈(mo)(mo)均在(zai)上(shang)(shang)面(mian)(mian)顯著,在(zai)下(xia)(xia)(xia)面(mian)(mian)凸起(qi);葉柄圓柱(zhu)形(xing)(xing),長(chang)4-5厘(li)米(mi)(mi),稀達(da)7厘(li)米(mi)(mi),幼時(shi)被(bei)稀疏(shu)的(de)(de)(de)短(duan)柔毛(mao)(mao)(mao)。兩性(xing)(xing)花(hua)(hua)(hua)(hua)(hua)(hua)與雄(xiong)(xiong)(xiong)花(hua)(hua)(hua)(hua)(hua)(hua)同(tong)株(zhu),由多(duo)數的(de)(de)(de)雄(xiong)(xiong)(xiong)花(hua)(hua)(hua)(hua)(hua)(hua)與1個雌花(hua)(hua)(hua)(hua)(hua)(hua)或(huo)兩性(xing)(xing)花(hua)(hua)(hua)(hua)(hua)(hua)成近球形(xing)(xing)的(de)(de)(de)頭狀花(hua)(hua)(hua)(hua)(hua)(hua)序(xu),直徑約2厘(li)米(mi)(mi),著生于幼枝(zhi)(zhi)(zhi)的(de)(de)(de)頂(ding)端(duan),兩性(xing)(xing)花(hua)(hua)(hua)(hua)(hua)(hua)位(wei)于花(hua)(hua)(hua)(hua)(hua)(hua)序(xu)的(de)(de)(de)頂(ding)端(duan),雄(xiong)(xiong)(xiong)花(hua)(hua)(hua)(hua)(hua)(hua)環繞于其周圍,基(ji)部具(ju)紙(zhi)質(zhi)(zhi)、矩圓狀卵形(xing)(xing)或(huo)矩圓狀倒(dao)卵形(xing)(xing)花(hua)(hua)(hua)(hua)(hua)(hua)瓣狀的(de)(de)(de)苞片2-3枚,長(chang)7-15厘(li)米(mi)(mi),稀達(da)20厘(li)米(mi)(mi),寬(kuan)(kuan)3-5厘(li)米(mi)(mi),稀達(da)10厘(li)米(mi)(mi),初淡(dan)綠(lv)(lv)(lv)色(se)(se)(se)(se),繼變(bian)為(wei)乳白色(se)(se)(se)(se),后(hou)變(bian)為(wei)棕(zong)黃色(se)(se)(se)(se)而(er)脫(tuo)落(luo)。雄(xiong)(xiong)(xiong)花(hua)(hua)(hua)(hua)(hua)(hua)無(wu)花(hua)(hua)(hua)(hua)(hua)(hua)萼及(ji)花(hua)(hua)(hua)(hua)(hua)(hua)瓣,有雄(xiong)(xiong)(xiong)蕊(rui)1-7,長(chang)6-8毫米(mi)(mi),花(hua)(hua)(hua)(hua)(hua)(hua)絲纖細,無(wu)毛(mao)(mao)(mao),花(hua)(hua)(hua)(hua)(hua)(hua)藥橢(tuo)圓形(xing)(xing),紫(zi)色(se)(se)(se)(se);雌花(hua)(hua)(hua)(hua)(hua)(hua)或(huo)兩性(xing)(xing)花(hua)(hua)(hua)(hua)(hua)(hua)具(ju)下(xia)(xia)(xia)位(wei)子(zi)房(fang),6-10室,與花(hua)(hua)(hua)(hua)(hua)(hua)托合生,子(zi)房(fang)的(de)(de)(de)頂(ding)端(duan)具(ju)退化的(de)(de)(de)花(hua)(hua)(hua)(hua)(hua)(hua)被(bei)及(ji)短(duan)小的(de)(de)(de)雄(xiong)(xiong)(xiong)蕊(rui),花(hua)(hua)(hua)(hua)(hua)(hua)柱(zhu)粗(cu)(cu)壯,分(fen)成6-10枝(zhi)(zhi)(zhi),柱(zhu)頭向外平展,每室有1枚胚珠(zhu),常(chang)(chang)下(xia)(xia)(xia)垂(chui)。果實為(wei)長(chang)卵圓形(xing)(xing)核(he)果,長(chang)3-4厘(li)米(mi)(mi),直徑15-20毫米(mi)(mi),紫(zi)綠(lv)(lv)(lv)色(se)(se)(se)(se)具(ju)黃色(se)(se)(se)(se)斑點,外果皮(pi)很(hen)薄,中果皮(pi)肉質(zhi)(zhi),內(nei)果皮(pi)骨質(zhi)(zhi)具(ju)溝紋,種子(zi)3-5枚;果梗(geng)粗(cu)(cu)壯,圓柱(zhu)形(xing)(xing)。花(hua)(hua)(hua)(hua)(hua)(hua)期4月,果期10月。
珙(gong)桐喜歡生(sheng)長在海拔1500-2200米的(de)潤濕的(de)常綠(lv)闊葉落葉闊葉混交林中。多生(sheng)于(yu)空氣陰濕處,喜中性(xing)或微酸(suan)性(xing)腐殖質深厚的(de)土(tu)壤,在干燥(zao)多風、日光直(zhi)射之處生(sheng)長不良,不耐(nai)瘠薄,不耐(nai)干旱(han)。幼苗生(sheng)長緩慢,喜陰濕,成年樹(shu)趨于(yu)喜光。
珙(gong)(gong)(gong)桐分布區(qu)(qu)的氣(qi)候為(wei)(wei)涼爽濕潤(run)型(xing),濕潮多(duo)雨(yu),夏涼冬季(ji)較(jiao)溫(wen)和(he),年平均(jun)氣(qi)溫(wen)8.9~15℃,1月(yue)平均(jun)氣(qi)溫(wen)0.43~3.60℃,7月(yue)平均(jun)氣(qi)溫(wen)18.4~22.5℃,年降水量(liang)600~2600.9mm,大于10℃活動(dong)積溫(wen)2897.0~5153.3℃。珙(gong)(gong)(gong)桐分布區(qu)(qu)的土壤多(duo)為(wei)(wei)山(shan)(shan)地(di)黃(huang)壤和(he)山(shan)(shan)地(di)黃(huang)棕壤,pH在4.5~6.0,土層較(jiao)厚,多(duo)為(wei)(wei)含有大量(liang)礫石碎片的坡積物,基巖(yan)為(wei)(wei)沙巖(yan)、板巖(yan)和(he)頁(ye)巖(yan)。珙(gong)(gong)(gong)桐多(duo)分布在深切(qie)割的山(shan)(shan)間溪溝(gou)兩側,山(shan)(shan)坡溝(gou)谷地(di)段,山(shan)(shan)勢(shi)非常陡峻,坡度約在30°以上。
在(zai)林中自然掉落的果(guo)實自行(xing)萌發(fa)的極少。要(yao)想人工繁殖珙(gong)桐(tong)(tong)與(yu)光葉珙(gong)桐(tong)(tong)則首先(xian)必須對果(guo)實進行(xing)破碎處理。幼苗(miao)階段需搭棚庇蔭并保持苗(miao)床濕潤。扦插宜用嫩枝(zhi)作插穗,于5~7月進行(xing)。高壓可于春(chun)季在(zai)一年生健(jian)壯枝(zhi)條的基(ji)部進行(xing)。苗(miao)木(mu)移(yi)栽(zai)宜在(zai)落葉后或(huo)翌春(chun)芽(ya)苞萌動前進行(xing)。起苗(miao)時不可傷根皮和頂芽(ya),對這長(chang)側(ce)根、側(ce)枝(zhi)可以適當(dang)修剪,栽(zai)植(zhi)時要(yao)求(qiu)穴(xue)大底平,苗(miao)正根展,并灌足定根水。
果實破碎處理的(de)方法有以下(xia)3種:
1.將收集(ji)到(dao)的果(guo)實倒在碓窩中,如搗米一樣(yang),用(yong)(yong)木(mu)棰反(fan)復敲(qiao)打,并注意用(yong)(yong)力適度。如用(yong)(yong)力太小,果(guo)皮不能完(wan)全脫離,而用(yong)(yong)力太猛,又會搗碎種子。將搗碎的果(guo)實用(yong)(yong)清水洗凈,拌上草木(mu)灰(hui)后即可播種。
2.將成熟的(de)果實直(zhi)接堆放(fang)在陰暗潮濕的(de)露(lu)地(di),任其自(zi)然(ran)冷凍,促進生理轉(zhuan)化(hua),使果肉爛掉,果核殼凍脆(cui)。堆置3個月的(de)平(ping)均氣溫為(wei)6.9℃時(shi),種子發(fa)芽(ya)率為(wei)92.6%,而平(ping)均氣溫為(wei)-2.5℃時(shi)則發(fa)芽(ya)率可高達98%以上。
3.最簡便易(yi)行的方法是將成熟的果(guo)實(shi)倒(dao)(dao)入有蓋的糞(fen)便桶,桶中注滿新鮮人尿,全部淹(yan)沒果(guo)實(shi)。經6至7周,果(guo)肉及(ji)果(guo)核殼全部腐爛后(hou)再倒(dao)(dao)入竹(zhu)筐內(nei),用(yong)清水沖(chong)洗,將種(zhong)子(zi)拌上(shang)草木灰后(hou)即可(ke)播種(zhong)。此法在湖北省長(chang)陽土家(jia)族(zu)自治縣(xian)內(nei)廣(guang)泛采(cai)用(yong),出苗(miao)率均(jun)在95%以上(shang)。
選(xuan)擇排(pai)水良好(hao),既肥沃(wo)又(you)濕潤的砂壤(rang)(rang)土(tu)(tu)(tu)或(huo)壤(rang)(rang)土(tu)(tu)(tu)做苗(miao)床,苗(miao)床四周開溝(gou)深(shen)度(du)不得低于40厘(li)米(mi)(mi)。土(tu)(tu)(tu)壤(rang)(rang)pH值要(yao)求不嚴,即使含鹽量(liang)0.15%的土(tu)(tu)(tu)壤(rang)(rang),珙(gong)桐樹苗(miao)亦能生(sheng)長(chang)發育。播(bo)種(zhong)要(yao)用代(dai)森鋅、多菌靈、托(tuo)布津、福爾馬林等藥劑進行土(tu)(tu)(tu)壤(rang)(rang)消(xiao)毒并深(shen)翻。播(bo)種(zhong)前在苗(miao)田(tian)開溝(gou),深(shen)10至(zhi)15厘(li)米(mi)(mi),寬5至(zhi)8厘(li)米(mi)(mi),再將(jiang)處理好(hao)的種(zhong)子按10至(zhi)15厘(li)米(mi)(mi)距離放入溝(gou)中,覆土(tu)(tu)(tu)壓(ya)實并澆透水。
珙(gong)桐種(zhong)子破殼萌(meng)芽(ya)時不耐(nai)水(shui)濕,剛(gang)出(chu)(chu)(chu)(chu)土(tu)(tu)的(de)幼苗(miao)(miao)(miao)(miao)若長時間在陰(yin)濕環境(jing)中,則(ze)根、莖、葉易腐爛,且死亡(wang)率高。排水(shui)良好(hao)的(de)坡地作為苗(miao)(miao)(miao)(miao)床出(chu)(chu)(chu)(chu)苗(miao)(miao)(miao)(miao)率高。因此,種(zhong)子萌(meng)發至(zhi)出(chu)(chu)(chu)(chu)現真(zhen)葉前應(ying)(ying)(ying)注(zhu)意土(tu)(tu)壤不能太濕。如遇(yu)長時間陰(yin)雨天氣(qi),除(chu)注(zhu)意做(zuo)好(hao)排水(shui)防澇工作外,還要噴1000倍液的(de)托(tuo)布津或500倍液的(de)代森鋅。一(yi)般(ban)情況(kuang)下,珙(gong)桐種(zhong)子在月平均(jun)(jun)氣(qi)溫(wen)(wen)0.56℃,旬平均(jun)(jun)氣(qi)溫(wen)(wen)-0.43℃時開(kai)始(shi)萌(meng)動。月平均(jun)(jun)氣(qi)溫(wen)(wen)達到(dao)(dao)2.3℃,旬平均(jun)(jun)氣(qi)溫(wen)(wen)為3.5℃時幼苗(miao)(miao)(miao)(miao)即開(kai)始(shi)出(chu)(chu)(chu)(chu)土(tu)(tu)。但剛(gang)出(chu)(chu)(chu)(chu)土(tu)(tu)的(de)幼苗(miao)(miao)(miao)(miao)不耐(nai)低溫(wen)(wen),如遇(yu)寒(han)潮(chao),應(ying)(ying)(ying)當預先(xian)架設密(mi)封的(de)塑料薄膜棚防寒(han)。幼苗(miao)(miao)(miao)(miao)真(zhen)葉出(chu)(chu)(chu)(chu)齊(qi)后(hou),即可施一(yi)次0.5%至(zhi)1%的(de)復(fu)合液肥或低濃度人糞尿液壯苗(miao)(miao)(miao)(miao),同時除(chu)凈田間雜草。當年(nian)幼苗(miao)(miao)(miao)(miao)即可長到(dao)(dao)30至(zhi)50厘米(mi)高,第二(er)年(nian)一(yi)般(ban)可長到(dao)(dao)120至(zhi)150厘米(mi)。幼苗(miao)(miao)(miao)(miao)長到(dao)(dao)30厘米(mi)以上(shang),地徑(jing)粗達0.4厘米(mi)時就可出(chu)(chu)(chu)(chu)圃移(yi)栽(zai)(zai)定植。移(yi)苗(miao)(miao)(miao)(miao)時間宜選在落葉后(hou)或翌春萌(meng)芽(ya)前,注(zhu)意起苗(miao)(miao)(miao)(miao)時勿(wu)碰傷根皮(pi)和頂芽(ya)。對(dui)過于細長的(de)側(ce)根和側(ce)枝可進行適當回(hui)縮修剪。珙(gong)桐根系發達,移(yi)植時栽(zai)(zai)植穴要求穴大底平,必須苗(miao)(miao)(miao)(miao)正根展。回(hui)填土(tu)(tu)要分層搗實,根莖培土(tu)(tu)應(ying)(ying)(ying)比原土(tu)(tu)位高出(chu)(chu)(chu)(chu)15至(zhi)20厘米(mi)。移(yi)栽(zai)(zai)完畢(bi)要澆透定根水(shui),使土(tu)(tu)壤與根系充分密(mi)接。小(xiao)苗(miao)(miao)(miao)(miao)移(yi)栽(zai)(zai)成(cheng)片定植,應(ying)(ying)(ying)架設遮陽棚,使小(xiao)苗(miao)(miao)(miao)(miao)安全過夏。珙(gong)桐喜涼(liang)爽(shuang)濕潤氣(qi)候環境(jing),最好(hao)是與其他闊葉喬木或常綠喬木混(hun)栽(zai)(zai)。
育苗(miao)用一(yi)年生(sheng)枝(zhi)條(tiao)(tiao)(tiao)做插(cha)穗(sui),長(chang)15~20厘米,直徑0.3厘米以(yi)上,每個插(cha)穗(sui)上至少要有(you)2個節間、2個芽,切(qie)口平滑(hua)不傷皮。3月上旬,在(zai)(zai)土壤(rang)(rang)剛化凍、芽萌(meng)動前(qian)扦(qian)插(cha)。插(cha)前(qian)細致整地(di),施足基肥,使土壤(rang)(rang)疏松(song)、水(shui)分充(chong)足。行距(ju)20厘米,株距(ju)10厘米。以(yi)直插(cha)為主,插(cha)條(tiao)(tiao)(tiao)深度(du)因環境條(tiao)(tiao)(tiao)件(jian)而異。過深土壤(rang)(rang)氧氣不足,不利于(yu)插(cha)穗(sui)生(sheng)根;過淺枝(zhi)條(tiao)(tiao)(tiao)外(wai)露(lu)多,蒸發(fa)量大(da),插(cha)穗(sui)易失(shi)水(shui)干(gan)枯。如在(zai)(zai)扦(qian)插(cha)時氣候寒冷而干(gan)燥,插(cha)后(hou)上端應適當覆土;在(zai)(zai)溫暖、濕潤條(tiao)(tiao)(tiao)件(jian)下,上面第(di)一(yi)個芽子微露(lu)地(di)表(biao)即可(ke)。由于(yu)枝(zhi)條(tiao)(tiao)(tiao)有(you)極性現象,扦(qian)插(cha)時,切(qie)勿倒插(cha)。插(cha)后(hou)要踏(ta)實,使插(cha)穗(sui)和(he)土壤(rang)(rang)密接,嚴防插(cha)穗(sui)下端蹬空,插(cha)后(hou)立印灌透(tou)水(shui)。插(cha)穗(sui)成(cheng)活后(hou),要適時灌溉、松(song)土、除草、施肥和(he)防治病(bing)蟲。扦(qian)插(cha)育苗(miao)成(cheng)苗(miao)率在(zai)(zai)60%左右。扦(qian)插(cha)前(qian)若(ruo)用ABT生(sheng)根粉(fen)對插(cha)穗(sui)進行處理,成(cheng)苗(miao)率可(ke)提高10~20%。
觀賞價值
珙(gong)桐(tong)為世(shi)界著(zhu)名的(de)珍貴觀(guan)賞樹,常植(zhi)于池畔、溪(xi)旁及療養所、賓(bin)館、展(zhan)覽館附近(jin),并有和平的(de)象征意義(yi)。
經濟價值
材質沉(chen)重(zhong),是建筑的上(shang)等用材,可制(zhi)作(zuo)家(jia)具和作(zuo)雕(diao)刻材料。