Effect of returning hill terraced fields for farming to forestry and grass were surveyed based on fixed point observation for nine years continuously. The results showed that death rate of Popular cathayana, Ulmus pumila and Hippophae rhamnoides was 100%, 92% and 12.7% respectively in terraced fields.

通過對湟源地區(qū)陰坡梯田退耕還林還草工程連續(xù)9年樣區(qū)定點觀測，結(jié)果表明一区二区三区四区欧美日韩，在梯田栽植的楊樹到第9年100%死亡99色色，榆樹的成活率只有8%，沙棘的成活率為87.3%A片性爱视频网址，檸條的成活率達100%在线观看激情无码毛片，但長勢不旺。

Ulmus pumila L. var. sabulosa is an indigenous plant in Hunshandake sandy land.

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Ulmus lamellosa ; Community characteristics ; Flora ; Species diversity

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Mongolica and Ulmus laciniata populations were aggregated distribution; they displayed different degrees of aggregation intensity during different times of forest conservation; aggregation intensity of populations inclined as a whole.

封山育林一般是針對采伐跡地、火燒跡地或棄耕農(nóng)田等宜林地采取的營林措施久久免费精品国产72精品九九。20世紀80年代以后我國封山育林的理論與應用技術(shù)研究均得到了迅速發(fā)展最近中文字幕免费视频在线，研究內(nèi)容涉及封山育林后的分布格局、群落類型www。射、營養(yǎng)動態(tài)等領域[1]91在线亚洲视屏。

The injury tolerance of cell plasma membrane and the correlative enzymes activities of plasma-membrane protection system in the Ulmus pumila leaves treated by nine concentrations (0.3%, 0.6%, 0.9%. 1.2%, 1.5%, 1.8%, 2.1%, 2.4%, 3.0%) of Na2CO3 and NaHCO3 mixtures were studied in a greenhouse of Northeast Forestry University, Harbin, China.

在東北林業(yè)大學育種基地，利用9種濃度(0.3%国产精品无码三级在线播放一区、06%欧洲一级毛片、0.9%、1.2%免费一极a片、1.5%曰本另类女同专区久久精品、1.8%www69炮、2.1%、2.4%日韩毛片毛片久久精品、3.0%)的Na2CO3和NaHCO3混合液對白榆扦插苗進行脅迫處理欧美色日，探討其在鹽脅迫下，細胞質(zhì)膜的傷害程度和質(zhì)膜保護系統(tǒng)相關酶的活性永久免费A片在线观看全网站妓女。

These pollen maps show significant vegetation changes during the past 10 000 years in the current forest regions of Northeast China, with the early Holocene characterized by the widely distributed Birch, the mid-Holocene by the development of temperate deciduous forest mainly consisting of Quercus and Ulmus, and the late Holocene by the marked increase in Pinus abun dance and the development of temperate mixed conifer and deciduous forest.

花粉圖展示了東北地區(qū)植被演化的主要特征欧美大尺度免费性交。樺樹在全新世初期遍布從三江平原到遼東半島南端的東北東部地區(qū)，在森林中占據(jù)絕對優(yōu)勢地位黄片a级a级a级；榆屬和櫟屬等闊葉喬木在早中全新世的大部分時間內(nèi)是東部森林中的主要種類国产wwwww视频；在大約5kaBP以后，松屬在東北現(xiàn)在的森林地區(qū)開始增加99re热这里有精品，云国产二级AV无码免费久久、冷杉屬也表現(xiàn)出較明顯擴大，中北部地區(qū)的森林覆蓋度可能比原來增大了免费看黄色视频免费看。

According the difference of plant community in Daqinggou Nature Reserve, the environment was divided into 7 kinds of habitats, they are Fraxinus mandshurica plant community, Quercus mongolicus plant community, Ulmus macrocarpa plant community, conifer community, lakefront plant community, paddy field plant community and grassplot plant community in sandlot.

按照植物群落的不同將保護區(qū)內(nèi)的環(huán)境劃分為7種生境日韩美女淫乱网，分別為水曲柳植物群落、蒙古櫟植物群落永久免费不卡A片在线观看全网站、大果榆植物群落爱搞免费、針葉林植物群落、湖邊濕地植物群落日韩高清视频免费观看、稻田植物群落和沙丘草地植物群落800级毛片。

The results indicated that the growth of 3-year-old Prunus salicina was significantly higher than that of the other species, such as 139.1% and 153.7% higher than Toona sinensis and Juglans regia in height growth, respectively. The maximum percentage of DBH more than 1.0 cm was 91.9% for P. salicina. Next were 49.5% and 48.8% for Ulmus pumila and Pteroceltis tatarinowii, respectively. The contents of total N, total P and total K ranged from 1.36% to 2.52% in the leaves of testing species. The highest content of total N and total P was found in the leaves of Catalpa bungei, while the highest content of total K was observed in P. saltcina leaves. The results indicated that P. salicina, P. tatarinowii, U. pumila had well adaptability on the Karst area both in the growth status and the improvement to the soil with the fallen leaf.

結(jié)果表明：(1)3年生冰脆李的生長量明顯優(yōu)于其他樹種，其高生長比香椿亚洲欧美日韩精品一区、核桃分別大139.1%和153.7%日本在线视频中文字幕；植株胸徑大于等于1.0 cm株數(shù)的百分比以冰脆李最高達到91.9%，其次是榆樹和青檀禁止18岁以下观看,黄片，分別是49.5%和48.8%三级国产精品；(2)8個樹種落葉的全N、全P和全K的總含量變動為1.36%~2.52%偷拍照片网，其中全N男人插女人逼逼的视频、全P含量以滇楸最高，全K含量以冰脆李最大国产毛片在线看；(3)從各樹種落葉前后各元素含量及其轉(zhuǎn)移情況看日日插人人插，冰脆李、青檀表現(xiàn)出對大部分營養(yǎng)元素具有較高的循環(huán)利用養(yǎng)分或保持養(yǎng)分的能力国产A片址一网，而香椿及刺槐相對較弱欧美黑人XXXX性高清视频。

Extraction of genome DNA ligneous plant ; Ulmus Lamellosa ; Elaeagnus mollis ; Ziziphus Jujuba

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The proportions of the main tree species (Quercus mongolica, Ulmus pumila, Fraxinus mandshurica, Juglans mandshurica) at di...

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