福林酚比色法和紫外分光光度法測定蟲茶中總多酚含量的比較研究

鄧剛，母健菲，劉玉琪，孫鵬

(重慶第二師范學(xué)院 生物與化學(xué)工程系， 重慶 400067)

摘要：本文采用了紫外分光光度法和福林酚比色法兩種方法測定蟲茶中總多酚的含量。福林酚比色法在10~60 μg/ml范圍內(nèi)，呈良好線性關(guān)系，R2=0.9997，加標(biāo)回收率為99.8%，相對標(biāo)準(zhǔn)偏差為1.27%，可用于蟲茶多酚的測定，且方法穩(wěn)定性良好；紫外分光光度法在5~30 μg/ml范圍內(nèi)，呈良好線性關(guān)系，R2=0.9995;加標(biāo)回收率為100.2%，相對標(biāo)準(zhǔn)偏差為0.87%，可用于蟲茶多酚的測定，且方法穩(wěn)定性良好。但是福林酚比色法測得多酚含量明顯高于紫外分光光度法。

關(guān)鍵詞：蟲茶； 多酚； 福林酚比色法； 紫外分光光度法

收稿日期：2015-07-24

基金項(xiàng)目：重慶第二師范學(xué)院2014年大學(xué)生科研項(xiàng)目(2014041)

通訊作者:

作者簡介：鄧剛(1994-),男,在讀本科生,研究方向?yàn)槭称贩治雠c檢測；孫鵬(1983-),男,講師, 研究方向：食品分析與檢測。

中圖分類號：TS272.7

文獻(xiàn)標(biāo)識碼：A

文章編號：1008-6390(2015)05-0167-03

Abstracts of Major Papers in Issue

一、引言

中國是茶葉生產(chǎn)和消費(fèi)的大國。市場上茶葉種類繁多，其中，“非茶之茶——蟲茶”受到越來越多消費(fèi)者的青睞，其來源與普通茶葉有很大區(qū)別，經(jīng)常以保健茶或藥用茶的形式出現(xiàn)[1]。蟲茶，又叫“蟲釀茶[2]”，是我國特有的林業(yè)資源昆蟲產(chǎn)品，是傳統(tǒng)出口的特種茶[3]，由化香夜蛾、米黑蟲等昆蟲幼蟲取食化香樹、苦茶等植物后所排出的糞粒制得。據(jù)記載，蟲茶具有清熱、祛暑、解毒、健胃、助消化等功效，對腹瀉、鼻衄、痔出血和牙齦出血均有較好療效[4]。據(jù)研究，蟲茶中富含多酚類物質(zhì)，是其主要的活性成分，多酚在植物中也廣泛存在，并且與植物的褐變、抗氧化性能力密切相關(guān)。多酚類物質(zhì)因?yàn)槠洫?dú)特的分子結(jié)構(gòu)，有很強(qiáng)的抗氧化性以及螯合性，能很好地清除人體內(nèi)的自由基，起到抗氧化抗衰老的效果[5]。

多酚類化合物具有酚羥基結(jié)構(gòu)，有較強(qiáng)的紫外吸收，紫外分光光度法(UV法)是測定蟲茶中總多酚的常用方法[6]。福林酚比色法(福林酚法)是酚羥基與福林(Folin)酚試劑反應(yīng)，產(chǎn)生藍(lán)色復(fù)合物，也是檢測總多酚常用方法[7]。本文通過紫外分光光度法和福林酚比色法測定蟲茶中總多酚的含量，并對兩種方法進(jìn)行比較研究。

二、材料與方法

(一)試驗(yàn)儀器、材料和藥品規(guī)格

日本島津公司，UV-2550紫外可見分光光度計；江蘇正基儀器有限公司，80-2離心機(jī)；上海舜宇恒平科學(xué)儀器有限公司，F(xiàn)A2004分析天平。

蟲茶樣品，來自廣西桂林；沒食子酸標(biāo)準(zhǔn)品，上海金穗生物科技有限公司；Folin-Ciocalteu試劑，上海荔達(dá)生物科技有限公司；亞鐵氰化鉀、冰乙酸、乙酸鋅等均為分析純，重慶博藝化學(xué)試劑有限公司；水為自制重蒸水。

(二)試驗(yàn)方法

1.蟲茶總多酚的提取

取蟲茶樣品1 g，精密稱定，置燒杯中，加水50 ml，煮沸1 min，將煎煮液和樣品倒入100 ml容量瓶中，并用適量水清洗燒杯，清洗液一并加入容量瓶中，放冷至室溫，加水定容至刻度，搖勻[8]。將該樣品溶液靜止沉淀30 min，精密量取上清液10 ml置50 ml容量瓶中，加20 ml水，搖勻，緩慢加入1 ml乙酸鋅溶液及1 ml亞鐵氰化鉀溶液，加水至刻度，混勻，靜置30 min后，后置離心機(jī)中，4000 r/min離心5 min。上清液用干燥濾紙過濾，棄去初濾液，取續(xù)濾液，即得供試品溶液。

乙酸鋅溶液：稱取21.9 g乙酸鋅，記入3 ml冰乙酸，加水溶解并稀釋至100 ml。

亞鐵氰化鉀溶液：稱取10.6 g亞鐵氰化鉀，加水溶解并稀釋至100 ml。

2.福林酚比色法測定多酚含量

另取沒食子酸標(biāo)準(zhǔn)品100 mg，精密稱定，置1.00 ml容量瓶中，加適量水，振搖使其溶解，加水至刻度，即為沒食子酸標(biāo)準(zhǔn)溶液[9]。分別量取沒食子酸標(biāo)準(zhǔn)溶液1.5 ml、1.25 ml、1 ml、0.75 ml、0.50 ml、0.25 ml置25 ml具塞比色管中，加入0.5 ml福林酚試劑混合均勻，再加入1 ml 15%Na2CO3溶液，混勻后定容至25 ml，將混合液置于55℃恒溫水溶中保溫5 min。冷卻至室溫后，于760 nm波長下測定吸光度，重復(fù)3次，繪制標(biāo)準(zhǔn)曲線[10]。

精密量取1項(xiàng)下供試品溶液5 ml，加入0.5 ml福林酚試劑混合均勻，再加入1 ml 15%Na2CO3溶液，混勻后稀釋至10 ml，將混合液置于75℃恒溫水溶中保溫10 min。冷卻至室溫后，于760 nm波長下測定吸光度，重復(fù)3次，計算多酚含量。

3.紫外分光光度法測定多酚含量

精密量取2項(xiàng)下的沒食子酸標(biāo)準(zhǔn)溶液1.5 ml置100 ml容量瓶中，加水稀釋至刻度，在200-400 nm波長范圍內(nèi)掃描，重復(fù)3次，選取280 nm為測定波長。另取標(biāo)準(zhǔn)品溶液稀釋成濃度5、10、15、20、25、30 μg/ml的溶液，在280 nm波長測定吸光度[11]，重復(fù)3次，繪制標(biāo)準(zhǔn)曲線[12]。

取1項(xiàng)下供試品溶液，在280 nm波長下測定吸光度，重復(fù)3次，計算多酚含量。

4.精密度的測定

分別取5個蟲茶樣品，照1-3項(xiàng)下方法，在相同條件下平行測定，檢驗(yàn)方法的精密度。

5.回收率的測定

分別取4個蟲茶樣品，以其中1份為基準(zhǔn)，其他3份照方法1配制成供試品溶液，精密量取5 ml，分別加入相當(dāng)于樣品含量80%、100%、120%的沒食子酸標(biāo)準(zhǔn)溶液，定容至10 ml。照1-2項(xiàng)下測定方法，測定多酚含量。每份樣品平行測定6次，計算回收率，并根據(jù)平行測定結(jié)果計算相對標(biāo)準(zhǔn)偏差。

6.排除沉淀劑對多酚測定的影響

為了驗(yàn)證沉淀劑對多酚的影響：取沒食子酸標(biāo)準(zhǔn)溶液4 ml置100 ml容量瓶中，加20 ml水，搖勻，緩慢加入1 ml乙酸鋅溶液及1 ml亞鐵氰化鉀溶液，加水至刻度，混勻，靜置30 min后，置離心機(jī)中，4000 r/min離心5 min。上清液用干燥濾紙過濾，棄去初濾液，取續(xù)濾液在760 nm測定吸光度，重復(fù)5次。

7.樣品穩(wěn)定性考察

穩(wěn)定性實(shí)驗(yàn)的目的是考察樣品在溫度、濕度、光照的影響下隨時間變化的規(guī)律，為樣品的生產(chǎn)、包裝、貯存、運(yùn)輸調(diào)劑提供科學(xué)依據(jù)，同時通過實(shí)驗(yàn)建立樣品的有效期[13]。

取蟲茶樣品適量置培養(yǎng)皿中，攤成≤10 mm厚薄層，進(jìn)行以下實(shí)驗(yàn)：

1)高溫實(shí)驗(yàn)供試品開口置適宜的潔凈容器中，在60℃下放置10天，于第5天和第10天取樣，照2項(xiàng)下方法測定多酚含量。

2)高濕度實(shí)驗(yàn)供試品開口置恒濕密閉容器中，在25℃相對濕度90%±5%條件下放置10天，于第5天和第10天取樣，照2項(xiàng)下方法測定多酚含量。

3)強(qiáng)光照實(shí)驗(yàn)供試品開口放在裝有日光燈的光照箱內(nèi)，于照度為4500 lx±500 lx的條件下放置10天，于第5天和第10天取樣，照2項(xiàng)下方法測定多酚含量。

每種影響因素平行測定3份。

三、結(jié)果與分析

(一)標(biāo)準(zhǔn)曲線和線性范圍的確定

1.福林酚比色法標(biāo)準(zhǔn)曲線

得到標(biāo)準(zhǔn)曲線y=0.0162x-0.0113，相關(guān)系數(shù)r=0.9997。其中，y為吸光度值，x為沒食子酸溶液的濃度，計算得線性范圍為10~60 μg/ml。由此可知，標(biāo)準(zhǔn)溶液濃度和檢測限響應(yīng)值呈良好線性關(guān)系，說明該方法靈敏度較高。

2.紫外分光光度法標(biāo)準(zhǔn)曲線

得到標(biāo)準(zhǔn)曲線y=0.0343x-0.0501，相關(guān)系數(shù)r=0.9995。其中，y為吸光度值，x為沒食子酸溶液的濃度，計算得線性范圍為5~30 μg/ml。由此可知，標(biāo)準(zhǔn)溶液濃度和檢測限響應(yīng)值呈良好線性關(guān)系，說明該方法靈敏度較高。

(二)精密度和加標(biāo)回收率

1.福林酚比色法

測定結(jié)果見表1，福林酚比色法的加標(biāo)回收率在97.6%到101.9%范圍內(nèi)，相對標(biāo)準(zhǔn)偏差在1.0%到1.7%范圍內(nèi)，可用于蟲茶多酚的提取。

2.紫外分光光度法

測定結(jié)果見表1，紫外分光光度法的加標(biāo)回收率在98.8%到101.8%范圍內(nèi)，相對標(biāo)準(zhǔn)偏差在0.8%到1.0%范圍內(nèi)，可用于蟲茶多酚的提取。

結(jié)果表明，福林酚比色法測得的平均加標(biāo)回收率為99.8%，RSD為1.27%；紫外分光光度法測得的平均加標(biāo)回收率為100.2%，RSD為0.87%。紫外分光光度法的重復(fù)性較福林酚比色法更好[12]，均具有較高的精密度，符合試驗(yàn)要求。

表1　回收率

表2　含量測定結(jié)果

3.含量測定結(jié)果比較

從表2知，福林酚比色法的RSD為1.4%，紫外分光光度法的RSD為1.3%，兩種方法均具有較高的精密度，符合實(shí)驗(yàn)要求。福林酚比色法測得多酚

含量明顯高于紫外分光光度法。

(三)沉淀劑對多酚測定的影響

測定結(jié)果見表3，兩種方法在加入沉淀劑后的測定濃度和沒食子標(biāo)準(zhǔn)液濃度并沒有太大差異，可以排除沉淀劑對多酚測定的影響。福林酚比色法加入沉淀劑后測定濃度的RSD為1.6%，紫外分光光度法加入沉淀劑后的測定濃度的RSD為1.9%，兩種方法都具有較好的精密度，結(jié)論可靠。

(四)穩(wěn)定性實(shí)驗(yàn)

測定結(jié)果見表4，多酚含量在高溫條件下隨時間增加逐漸減少，在高濕度和高光照下基本含量保持不變。

表3　沉淀劑對多酚的影響

表4　穩(wěn)定性實(shí)驗(yàn)結(jié)果

四、結(jié)果和討論

福林酚比色法和紫外分光光度法測定多酚含量的方法準(zhǔn)確度、精密度、加標(biāo)回收率均在可接受范圍內(nèi)，兩種方法均可用于多酚含量的測定，但福林酚比色法和紫外分光光度法測定蟲茶總多酚含量存在顯著性差異。福林酚比色法檢測成本相對較高，紫外分光光度法檢測成本低、操作簡單、重復(fù)性好、精密度高。福林酚比色法和紫外分光光度法中沉淀劑對多酚含量的測定沒有影響。高溫對蟲茶中多酚含量影響較大，而高濕度和高光照幾乎沒有影響，故蟲茶應(yīng)當(dāng)在陰涼處貯藏。

目前，福林酚比色法和紫外分光光度法常用于多酚含量的分析，多酚含量測定的國家標(biāo)準(zhǔn)為福林酚比色法。本文發(fā)現(xiàn)兩種方法所測多酚含量具有較大差異，造成的原因可能是福林酚比色法測定的是還原能力，即茶葉中酚羥基被高價鎢氧化后形成藍(lán)色物質(zhì)[14]，其中酚羥基包括含有酚羥基的氨基酸、蛋白質(zhì)和具有還原能力的抗壞血酸[15]；紫外分光光度法測定結(jié)果是帶有酚羥基的物質(zhì)，由于蟲茶中氨基酸、蛋白質(zhì)等含量豐富，導(dǎo)致福林酚試劑法測定的含量高于紫外分光光度法。

參考文獻(xiàn)：

[1]勵建榮,周李婷.中國蟲茶現(xiàn)狀及其研究開發(fā)思路[J].農(nóng)產(chǎn)品加工,2005(4):3-7.

[2]文禮章.中國昆蟲學(xué)會2000年學(xué)術(shù)年會議論文集[M].北京:中國科學(xué)技術(shù)出版社,2000:1127.

[3]韋誠忠.廣西大力開發(fā)蟲茶資源[J].中國藥業(yè),2001,10(10):14.

[4]雷鳴,盧曉黎.中國蟲茶資源及研究現(xiàn)狀[J].食品科學(xué),2001,22(11):101.

[5]李淑娟.茶多酚的保健和藥理作用研究進(jìn)展[J].西北藥學(xué)雜志,2010,25(1)78-79.

[6]賈有青,谷晶,閆書婷.茶葉中茶多酚含量的測定方法比較[J].中國藥茶,2014(01):21-22.

[7]程云環(huán),滕井通,薛建平,等.Folin-Ciocalteu比色法測定懷山藥零余子多酚含量的研究[J].赤峰學(xué)院學(xué)報,2013,29(5):17-19.

[8]許光明,彭新君,王彩君,等.三葉蟲茶中多酚類物質(zhì)離子沉淀法提取工藝研究[J].湖南中醫(yī)藥大學(xué)學(xué)報,2007,27(2):46-49.

[9]張雅麗,李建科,劉柳,等.五倍子沒食子酸研究進(jìn)展[J].食品工業(yè)科技,2013(10):386-390.

[10]趙曉娟,李敏儀,黃桂穎,等.Folin-Ciocalteu法測定蘋果醋飲料的總多酚含量[J].食品科學(xué),2013,34(08):31-35.

[11]陸蘭麗,王鳳玲,李榮,等.直接固體相紫外分光光度法測定茶葉中的茶多酚[J].食品科技,2005(5):72-74.

[12]楊雁芳,艾鐵民.紫外分光光度法測定松果菊提取物中多酚[J].中草藥,2005,36(11):1649-1650.

[13]國家藥典委員會.中華人民共和國藥典：二部[S].北京：中國醫(yī)藥科技出版社,2010:附錄199-201.

[14]張妙芬.茶葉中茶多酚含量測定方法的研究[J].化學(xué)工程與裝備,2012(5):152-155.

[15]黃皓,毛志方,涂云飛,等.兩種方法測定茶葉中茶多酚含量的比較[J].中國茶葉加工,2009(2):43-44.

[責(zé)任編輯王南山]

Experience analysis of democratic politics construction in western rural grassrootsby LIU Chun-ming, CHAI Peng, LIU Yuan-dongp.5

Since the foundation of our country, the development of democratic politics construction in western rural grassroots presents a special historical track and regional feature. In the era of promoting the western development and accelerating the western rural construction, it has realistic significance, teasing the development process of the democratic politics construction in western rural grassroots, summarizing the basic experience about it, and reasonably discussing its future developing trend, in order to promote the overall and coordinated development of western rural in social economy, politics and culture.

Key words: western rural; democratic politics construction of grassroots; development process; basic experience

From interpretation principles to coping strategies: philosophical revolution in Richard Rorty’s conceptby WANG Tian-minp.13

Based on Richard Rorty’s philosophical position of pragmatism, the change of modern philosophy can be concluded the changes from the interpretation principle to the coping strategies. This change shows the general picture: the origin change from curiosity to dilemmas, the function change from exploring truth and goodness to solving problem of times, the evolution change from solving age-old problems to transforming individual perspectives, and the mode change from narrative words to discussing public issues.

Key words: change of philosophy; interpretation principles; coping strategies

Empirical analysis of fiscal expenditure benefit based on small and medium enterprisesby WANG Xin, LI Dong-meip.21

Based on the “3-E” principle of evaluation index system, this paper analyzes the 159 data on fiscal expenditure implementation plan of China’s small and medium-sized enterprises (SMEs) from 2004 to 2014. To establish the benefit structure model of fiscal expenditure, it chooses five indicators to measure the financial expenditure efficiency — the Yield of SMEs Income Creating, the Arrival Rate of the Government Special Funds, the Proportion of the Fiscal Investment and Loan Program to Fiscal Expenditure, Employment Rate of SMEs, and the Yield of SMEs Patent Technique. With the help of analytic hierarchy process and Matlab2012b programming, it concludes that the dominant fiscal expenditure benefit factors are the Yield of SMEs Income Creating and the Yield of SMEs Patent Technique. Thus, it offers the following recommendations to realize the target of fiscal expenditure benefit maximization: to increase the investment of fiscal expenditure, to strengthen the management of the Government Special Funds and the Fiscal Investment and Loan Program, and to construct a multi-level fiscal expenditure system.

Key words: “3-E” principle; fiscal expenditure benefit; the development of SMEs; analytic hierarchy process

Value and tourism development of culture resources in Beijing-Hangzhou Grand Canal’s old brandby ZHANG Heng, LI Yong-lep.29

The old brand cultural resource of the Beijing-Hangzhou Grand Canal is part of the system of the Grand Canal cultural heritage. It enriches the cultural connotation and enhances the vitality of the Grand Canal. It is the carrier of the Grand Canal’s static culture in dynamic form. The tourism development from the perspective of protection and inheritance, drives the spread and inheritance of the old brand of the canal, and promotes the product innovation to obtain a certain economic benefits. During the tourism development, the canal old brand is suitable for the museum development mode, the agglomeration development mode, cooperative development mode, and tourism elements development mode.

Key words: the canal old brand; the Beijing-Hangzhou Grand Canal; value analysis; tourism development

Text problems in inscriptions arrangement: taking emendation and arrangement ofBeiyueAnKingTempleMonumentas an exampleby HE Shanp.33

Based on a comprehensive survey and comparative analysis of four types of inscriptions text fromBeiyueAnKingTempleMonument, this paper concludes that the copy text is more reliable, the block-printed and the typographic editions are of the second, both can be selected as the emendation master copy. Besides the problems such as mistakes in writing, subjective assume, the re-block-printed text and transcript are mainly based on secondary literature, lack of authenticity. So it should be careful to use this kind of text. It should not be commonly chosen as master text in the case of other text. It can be mainly used in the reference of emendation and arrangement.

Key Words: emendation and arrangement of inscriptions; text selection;BeiyueAnKingTempleMonument

On China’s media international communication ability from the perspective of being quoted by foreign media: taking related report of keywords “China’s president” as an exampleby GUO Guang-hua, HUANG Haop.47

The reference of the western mainstream newspapers to the Chinese media reports is one of the important windows to observe the international communication ability of Chinese media. Based on the report of the keywords “China’s president” (2014.1.16-2015.1.15) by 6 British and American newspapers and the related data of the past 9 years (2005.1.15-2014.1.15), the paper analyzes and concludes that the western media’s attention degree and the reference rate to the Chinese media reports has improved, but the attitude trends to be negative. The trust degree of western media to Chinese media report is to be improved, and the international communication ability of Chinese media can be further enhanced.

Key words: British and American newspapers; reference; Chinese media; communication ability

On film title translation from the perspective of eco-translatology: taking the Chinese translation ofThePursuitofHappynessas an exampleby ZHAO Hai-juanp.52

Eco-translatology focuses on the exploration of the common translation rules, defines translation activity as an alternative cycle of the translators’ selective activity of their adaptation to the eco-environment, and offers a new theoratical perspective and practical method to film title translation. Film title is the essence of rich content and culture, and is of high commercial values. The American filmThePursuitofHappynessgains high hits of box-office both at home and abroad, and sets a good example for determination movie with great warmth. This paper, taking the Chinese translation ofThePursuitofHappynessas an example, analyzes the translators’ selective and adaptive transformation from namely, linguistic, cultural and communicative dimensions, hoping the application of eco-translatology can provide a new thinking for the translation of film titles.

Key words: eco-translatology; film title translation;ThePursuitofHappyness; three-dimensional transformation

Interpretation Li Bai’s moon consciousness from the perspective of Yi-ologyby KANG Huai-yuanp.64

BaJiuWenYue,GuLangYueXing,YueXiaDuZhuoare the typical representatives of Li Bai’s moon consciousness. They are the warm dialogues between Li Bai and the nature, the life. The cultural core is closely rela-ted toZhouyi. Among all the poems of Li Bai, we appreciate not only his poetic beauty, but also the feelings of the universe philosophy. Li Bai’s moon consciousness is the poetic presentation of his universal consciousness in life, philosophy, and Yi-ology. This is related to the prosperous Yi-ology in Tang Dynasty.

Key words: Li Bai; the moon; consciousness; life; philosophy; Yi-ology

Incarnation of Jesus in “Hard Pan Trilogy”: image interpretation of Short Sammyby MA XI-wu, MA Yanp.82

In “Hard Pan Trilogy”, Short Sammy is an important figure, playing a key role in the spiritual life of the heroine Lucky and town residents. This paper analyzes the Jesus characteristics reflected from Sammy, and concludes that he is like an incarnation of Jesus. From this angle, this paper further explains Sammy’s role of spiritual mentor and guardian, and his spirit of facing sufferings calmly. The image of Sammy reflects the author’s liberal religious view.

Key words: Hard Pan Trilogy;TheHigherPowerofLucky; Jesus; Newbery

Predicament and breakthrough of the transformational development of newly-built local universities in Chinaby TIAN Zhen-huap.98

The transformational development of newly-built local universities is an important part of higher education development in recent years. The higher education in our country has gained continuous development and progress, but also a lot of problems, facing many difficulties. It is necessary for transformational development of newly-built local universities to clarify the basic connotation, to define the basic orientation, to correctly handle the relationship between theory and practice, to seek a breakthrough from many problems and predicaments, and to go out of a transformational development road with Chinese higher education characteristics.

Key words: local universities; transformational development; predicament and breakthrough

Enlightenment of foreign teacher education to the development of rural teachers’ professional knowledge in Western Chinaby QIN Bop.106

Based on the practice and experience of teacher education in foreign countries, this paper gets the results that teachers’ professional knowledge should be developed by taking the following measures: establishing teacher professional standards, improving teachers’ continue education laws and regulations, formulating teachers professional development planning, clearing knowledge development goals, innovating teachers’ continuing education training mode, establishing a sound system of teacher education, establishing the organization of teachers’ professional development, reforming teacher education system, giving full play to the advantages of the network platform, and so on. It has important and realistic significance to expand western rural teachers’ professional knowledge, and to promote professional development of teachers in China’s western rural areas.

Key words: foreign teacher education; western rural teachers; professional knowledge development; enlightenment

College students’ employment psychology: problems, attribution and strategiesby ZHAO Ding-guip.110

The pressure of college students’ employment is increasing, which makes the students’ psychological problems more prominent. It seriously affects the development of college students’ physical and mental health. Based on investigation and analysis of college students’ employment psychology, this paper finds that there are different degrees of psychological problems in three dimensions of cognition, emotion and behavior. These problems are the result of social, school and student. Only from these three aspects of the specific improvement measures, can effectively improve the psychological status of college students.

Key words: college students; employment psychology; control measures

Study on characteristics of China’s roof greeningby XU Jing, PENG Hui-ling, YANG Qing-weip.163

Based on the CNKI document database, by the methods of bibliometric analysis, SPSS programme, and ArcGIS mapping, this paper investigated China’s greening of urban roof (CGUR) in 1982-2014 to explore the research progress in the past 30 years and the future prospects. The results show that the annual publication rate of the CGUR in either 30 years (1982-2012) or 15 years (1998-2014) is similar to the established academic discipline of landscape ecology. The ArcGIS mapping of the spatial distribution indicates the CGUR is concentrated at the humid and semi-humid climate regions of the south and east China, and few at the arid and semi-arid regions of the west and north China. According to the multidisciplinary analysis, the CGUR mainly comprises engineering, biology, geography, architecture and forestry, especially architecture and forestry. Ultimately, in the present review research, inviting some biologists and ecologists to be the members of the CGUR is thought to be necessary, which may expand the research on the ecological effect of roof greening on the biodiversity protection so as to clarify the biological/ecological function of the green roof.

Key words: roof greening; plant ecology; urban geography; bibliometric analysis