2004 Vol. 21, No. 2

Articles
Radial variations of the timber properties of Pinus densifiora planted in different slope places
JIN Chun-de, ZHANG Mei-shu, WEN Gui-feng, LIU Ji-sheng2, ZHANG Peng
2004, 21(2): 119-124.
[Abstract](1703) [PDF](166)
Abstract:
The radial variation models and differences of the tracheid morphological and physico-mechanical characteristics of Pinus densifiora plantations in the below , middle and upper slopes in the Maoer Mountain Forestry Center in Yanji City were studied .The results showed that micro-fibril angle , basic density and the ratio of wall to diameter of P .densifiora plantations in the different slopes were magnificently different at the 0.01 level .The average values of ratio of wall to diameter of P .densifiora in the middle slope were 11.62 %and 16.45 %higher than those in the below slope and upper slope .And the average value of micro-fibril angle of the former was 54.31 % and 38.77 % less than the latter , and the average value of basic density was 10.5 % and 7.02 % higher .The variations results showed that P .densifiora plantation timber in the middle slope was the best structure material , and others was more suitable for the pulp materials .[ Ch , 9 fig .3 tab .6 ref .]
Mechanical properties and micro conformation of small Chinese fir cell before and after combing
LI Yan-jun, ZHANG Hong, ZHANG Bi-guang, XU Mei-rong
2004, 21(2): 125-129.
[Abstract](1242) [PDF](211)
Abstract:
A comparative study of the micro conformation and tensile strength of wood parallel to grain of small Chinese fir cell in the water saturation condition under different static pressures or before and after combing test was conducted .The best mechanical properties parameters of small Chinese fir under static pressure or by combing were gained in the study .The results showed that the best compression set of small Chinese fir was about 50 %.A few tracheids of small Chinese fir began to break when the compression set of small Chinese fir was greater than 30 %. The condition will turn serious with the increase in static pressure .Most of tracheids of small Chinese fir began to break when the compression set was greater than 50 %.However , the destruction rate slowed down and a few tracheid holes could be seen on the cross section of cell .The tensile test showed that tensile strength of wood along grain would be decrease with the increasing static pressure .[ Ch , 3 fig .1 tab .8 ref .]
Physico-mechanical properties of planted Phyllostachys praecox
YU Qiong-hua, YU You-ming, JIN Yong-ming, MA Ling-fei
2004, 21(2): 130-133.
[Abstract](1091) [PDF](219)
Abstract:
Physico-mechanical properties of planted Phyllostachys praecox were studied for the effective application of it .The results showed that age had a remarkable effect on the physico-mechanical properties .The radial shrinkage coefficient , chord shrinkage coefficient and cubage shrinkage coefficient decreased with the increase in age while the basic density , compression strength along grain , tensile strength along grain and bending strength increased with the age , and became stable at the age of 4 -5 years .From the bottom to the top , the moisture content and shrinkage coefficient reduced gradually ;the vascular bundle density , basic density and mechanical strength correspondingly increased .Judging by the properties , P .praecox of 4 -5 years old are suitable for cutting and applying .[ Ch , 3 tab .10 ref .]
Overlaying technology of paper impregnated thermosetting resins of Chinese fir orient laminated strand lumber
DU Chun-gui, LIU Zhi-kun, ZHANG Qi-sheng, ZHANG Hong, LOU Yong-sheng
2004, 21(2): 134-137.
[Abstract](1296) [PDF](164)
Abstract:
The feasibility of paper impregnated thermosetting resin overlaying technology of Chinese fir orient laminated strand lumber was studied to improve its physical and mechanical properties and surface quality , and promote its application and popularization .In the experiments , a veneer was added in paper impregnated thermosetting resins and Chinese fir orient laminated strand lumber and overlaying on its surface .The physical and mechanical properties of overlaying board were tested and its overlaying technology was analyzed for the optimum technology parameters .The results show that paper impregnated thermosetting resins overlaying technology of Chinese fir orient laminated strand lumber is practical ;the optimum parameters are as follows :2.5 MPa hot pressing pressure , 4-minute hot pressing and 160 ℃hot pressing temperature .[ Ch , 3 tab .11 ref .]
Study on vulnerability of xylem embolism in twigs of seven tree species
XIE Dong-feng, MA Lǜ-yi, WANG Hua-tian
2004, 21(2): 138-143.
[Abstract](939) [PDF](246)
Abstract:
The xylem embolism and moisture potential of one-year-old twigs of 7 tree species including Robina pseudoacacia ,Pyrus betulaefolia , Quercus acutissima , Melia azedarach , Ginkgo biloba , Pistacia chinensis and Acer mono in the north of China were studied with the `flushing method' in autumn .Embolism vulnerability curves of all 7 species were drawn .The results were as follows :(1)Maximum twig water conductivity of 7 tree species were 0.054 3 , 0.036 2 , 0.022 0 , 0.018 4 , 0.014 1 , 0.013 3 and 0.011 0 gcm-2s-1 ;(2)Branch moisture potential had a magnificent affect on xylem embolism .With the decrease in moisture potential , the xylem embolism became serious ; (3) Taking 50 % hydraulic conductance loss as the critical value of the embolism vnlnerability , we found out thatM .azedarach and P .chinensis were of the most embolism vulnerabiliy ;and R . pseudoacacia and Q .acutissima came in second ;the other three species were of least embolism vulnerability ; (4)When the twig moisture potentials descend to -4.5 , -3.8 , -4.2 , -3.6 , -4.7 , -4.5 and -4.3 MPa respectively , the maximum hydraulic conductivities of Q .acutissima , R .pseudoacacia and M .azedarach were about 94 %~ 96 %, G.bi loba and P .betulaefolia about 99 %, and P .chinensis only 78 %;(5)The embolism vulnerability curves of most species under test were in reciprocal forms ;those of R .pseudoacacia and M .azedarach were in index forms.They all had significantly fitting formulas .[ Ch , 2 fig .1 tab .20 ref .]
A study of application of solid-water in vegetation restoration
ZHAO Li-jun, LI Ji-yue, ZHU Li-qiong
2004, 21(2): 144-149.
[Abstract](970) [PDF](212)
Abstract:
To find a new way to promote the restoration of vegetation in arid areas, comparative studies of solid-water treatment , straw coverage and controlled groups were conducted in Qinghai Province and Sichuan Province of China . The results showed that solid water could provide water for seedlings for three months during the dry season .The survival rate of seedling with solid water was over 90 % on the average .The survival rates of Amygdalus sibirica , Ulmus pumila , Populus cathayana , Hippophae rhamnoides and Rhus typhina were 32.6 %, 26.7 %, 24.2 %, 7.4 % and 61.1 % higher respectively than the controlled groups .The decomposition rate of solid water was about 4-5 gd-1 .The rate at the end was a bit higher than that at the beginning .This provided necessary water for the seedlings in the fast-growing period and increased the survival rate of seedlings .The analysis of integrated cost showed that the technology of applying solid water to afforestation was especially applicable to the arid areas where the survival rate of seedlings was low .[ Ch , 3 fig .2 tab .10 ref .]
Simulation experiment of surveying forest land area with RTD GPS
GUAN Feng-ying, FENG Zhong-ke, WANG Xiao-kun, ZHOU Bin
2004, 21(2): 150-153.
[Abstract](1231) [PDF](227)
Abstract:
To study the precision of calculating forest land area and forest volume , lands of different areas and regular shapes were tested with real-time differential GPS (RTD GPS).The relative errors , variances and precision of the surveying results were calculated and analyzed .The results showed that the minimum surveying precision was 97.67 %, which could satisfy the precision demand for forest land area surveying in the study of various forest resources.With the increase in surveying area , the surveying precision of RTD GPS tended to improve .However , RTD GPS had its defect because the surveyors had to conduct on-the-spot survey , which was impractical for the survey of forest land of a large area .According to the actual analysis of forest land survey , RTD GPS is applicable to the precision test of the traditional survey of forest land area .It is more rapid and efficient than the traditional testing method and can ensure the precision .[ Ch , 1 fig .2 tab .8 ref .]
Sunlight sheds effect on earlier maturity of Myrica rubra
LI Xiu-ting, QIU Cheng-ming, WANGBai-po, ZHANGXin-hua, SHEN Ai-qiao
2004, 21(2): 154-158.
[Abstract](1186) [PDF](190)
Abstract:
Myrica rubra is used as a test material to study the temperature and monisture change of sunlight shed and its effects on the blossom , fruit development and earlier maturity of cv .Dingao .The result showed that the average temperature inside the shed at noon during J anuary and May was 20.8 -33.3 ℃, which was 11.4 ℃ higher than that outside .During cold current period , the temperature inside the shed was 4.8 -7.0 ℃higher than that outside .When the temperature outside the shed was reduced to -3.0 ℃, the inside temperature was 1.0 ℃. The soil temperature under the depth of 20 cm inside the shed was 12.0 -14.0 ℃, which was 5 -6.0 ℃higher than outside temperature ;the air moisture inside the shed was over 85 %, which was 4 %-5 %higher than that outside .Optimum temperature and moisture inside the shed caused the earlier bud and blossom by 15 -19 days . Fruits developed 2 weeks earlier than usual .The film of shed should be covered at the end of December .Earlier film covering had no effect on earlier maturity .The unit yield inside the shed was 8.9 thm-2 , 19.62 %higher than that outside .The economic benefit was 4.2 -5.7 times higher than usual .The establishment of M .rubra shed is discussed [ Ch , 2 fig .3 tab .10 ref .]
Bamboo charcoals effect on the soil characteristics and Fescue arundinacea growth
FU Qiu-hua, ZHANG Wen-biao, ZHONG Tai-lin3, ZHANGHong, JIANG Wen-wei
2004, 21(2): 159-163.
[Abstract](1128) [PDF](223)
Abstract:
Bamboo charcoal is kind of porous quality , containing many kinds of inorganic compounds , new materials of relatively big specific area .Fescue arundinacea is that one kind adapts to the south area in China and afforests the type lawn of cold season that plants .Bamboo charcoal to be constructed and shed in F .arundinacea lawn top layer soil by utilize different quantity different particle size .The result showed :Having constructed the soil of the bamboo charcoal , its physics and chemistry performance had obviously improved contents of element , such as N , P , K , Ca , Mg , etc ., and Zn , Cu , heavy metal content reduced .F .arundinacea taking root , taking leaf and grow had influenced in varying degrees .And the way a crop was growing , root , stem of F . arundinacea had also the best by constructing 200 g m-2 of charcoal quantity , charcoal soil improvement of bamboo that a diameter was smaller than 3 mm of charcoal .[ Ch , 4 tab .8 ref .]
A survey of ancient trees in Zhuji City JIN Guo-long , MENG Hong-fei
JIN Guo-long, MENG Hong-fei
2004, 21(2): 164-167.
[Abstract](990) [PDF](207)
Abstract:
There are 45 109 ancient trees , which belong to 38 families , 65 genus and 90 species in Zhuji City of Zhejiang Province .The oldest tree is 1 350 years old .The maximum diameter of a tree is 2.95 m.The suggestions on protecting old trees are put forward on the basis of the survey .[ Ch , 3 ref .]
Biomass models of organs of Pleioblastus amarus
LIN Xin-chun, FANG Wei, YU Jian-xin, YU Xue-jun, HU Chao-zong, ZHOU Lin
2004, 21(2): 168-171.
[Abstract](1164) [PDF](211)
Abstract:
Based on the biomass surveys of Pleioblastus amarus in Zhongtai Township of Yuhang District , Hangzhou , the matrix of correlation efficient among various organs of Pl .amarus were established .The best mathematical models of various bamboo organs and the diameter at breast heigh , height or lowest branch height were constructed through regression analysis .The models were as follows :mstem=13.439 5 D 2.0048 H0.442 5 ;mbranch=2 956.359 8 D 1.992 9 H-0.641 0 ;mleaf=43.746 7 -30.541 2 D +53.759 7 D2 ;mroot=270.956 0D 2.357 9 H -0.399 5 ;msubterranean stem=512.436 1 -175.936 0D +2.907 8H0 ;maboveground=432.446 8 -479.307 5D +422.828 5D2 ;mundergound=396.622 3 -53.286 9 D +2.877 5H0 ;mtotal=191.038 0D 1.198 6 H0 0.296 2。Using these models , the biomass of various organs of ramet and forest of Pl .amaruswere calculated respectively .This result had reference to the evaluation of productive potentialities and guidance of production of Pl .amarus .[ Ch , 4 tab .12 ref .]
Analysis of nutrient elements in various organs of Pleioblastus amarus
LIU Li, LIN Xin-chun, JIN Ai-wu, FENG Tian-xi, ZHOU Chang-pin, JI Zong-fu
2004, 21(2): 172-175.
[Abstract](1156) [PDF](199)
Abstract:
Main nutrient elements in various organs of Pleioblastus amarus at different ages were analyzed .The results showed that the contents of N , P and K in the stem , branch and subterranean stem decreaseal with the increasing age ;the content of Si increased with the age .And the contents of N , P , K and Si in various organs were ranked as follows :leaf branch subterranean stem root stem .Compared with Phyllostachys pubescens and Ph .nidularia , the contents of N , K and Si in stem , branch and leavewere higher while the contents of P in three bamboos had no difference .[ Ch , 6 tab .6 ref .]
Comparison of fruit nutrition components of Castanea henryi clones
JINGYun, LIANGYi-chi, YANGHua
2004, 21(2): 176-179.
[Abstract](1817) [PDF](199)
Abstract:
To select and promote high-quality and high-yield Castanea henryi , the contents of proteins , fat , soluble sugar and starches of different C .henryi clones , and the difference and correlation coefficient of nutrient components in nuts among clones were studied .The results showed that there were great significant difference in the contents of protein and fat of different clones .The contents of soluble sugar among different clones were significantly different .And there were no significant differences in the contents of starchesand nutrient components among clones . Q-system clustering analysis showed that the contents of proteins of 9 clones were above the medium level (150 g kg-1);the contents of fat of 16 clones were above the medium level (22 gkg-1);the contents of soluble sugar of 21 clones were above the medium level (100 gkg -1);and the contents of starches of 11 clones were above the medium level (580 g kg-1).So the different clones could be selected according to different requirements fornutrition .No.14 clone had the highest contents of all nutrients .[ Ch , 7 tab .10 ref .]
Field survey of south China tigers and their habitat evaluation in Hupingshan National Reserve
HUANG Xiang-yun, HU De-fu, TANG Xiao-ping, WANG Zhi-chen, LIU Wei-shi
2004, 21(2): 180-184.
[Abstract](1393) [PDF](198)
Abstract:
As a state natural reserve for forests and wild animals , Hupingshan Mountain in Hunan is an area where the evidences of the existence of south China tiger are often spotted in recent years.Sino-American united survey team for south China tiger conducted a survey in the reserve through October to December , 2001 with the ways and methods popular at home and abroad such as visiting local people , transect sampling , trail monitoring and infrared automatic photo-taking .No exact evidences of the existence of south China tiger in the reserve were found in this survey .However , the survey systematically investigated the habitat in this area and preliminarily evaluated the living conditions of south China tiger .Historically speaking , the reserve is an area where many south China tiger appear . It is still suitable for the living of south China tiger and will be an ideal base for the reintroduction of south China tiger .[ Ch , 2 tab .13 ref .]
A study of Web-based universal report form writer
WU Da-sheng, FAN Xue-hua, ZEN Song-wei, YU Qin-feng
2004, 21(2): 185-188.
[Abstract](2643) [PDF](173)
Abstract:
The forestry organizations take on a hierarchy structure and the span between two neighboring organizations is usually very large .The operation nature of the forest department determines that a lot of data should be reported to the superior organizations one level by another , which means the formats of a lot of data among management organizations of different levels are the same .Developing web-based universal report writer can decrease the systematic maintenance work and demanding requirements for userscomputers , which is important to administrative departments of the forestry , especially the forestry administrative departments of grass roots .The function characteristic of web-based universal report writer , system structure model and keys to the system designing are illustrated .[ Ch , 2 fig .6 ref .]
Bamboo industry in Lishui :community participated sustainable development model of mountain areas
LI Ming-hua, JIN Ling, ZHANG Xiao-fang
2004, 21(2): 189-193.
[Abstract](1281) [PDF](153)
Abstract:
The models of sustainable development of mountain areas and communities are basically consistent .A case study of the development of bamboo industry in Lishui , a mountainous city in the south of Zhejiang Province , was conducted by briefly concluding the backgrounds and process of the development of bamboo industry in Lishui and applying the theories of social development in mountain areas .The results show that driven by a strong desire for the development , the previous development in the mountain areas was a kind of blind imitation .The bamboo industry in Lishui had overcome the shortcoming and based itself upon the local resources .With the advanced participant community development model , industrialized market operating mechanism, effective combination of technology from other places and local technology , and the solution of issue of culture transformation , the sustainable development was achieved .[ Ch , 9 ref .]
On sustainable development of forest tourism in China
HU Jian-qiang, ZHANG Pei-cheng, MEI Yan
2004, 21(2): 194-197.
[Abstract](1284) [PDF](220)
Abstract:
Forest parks and natural reserves all over China featuring beautiful sights , dense forests , rich plant and animal resources and pleasant ecological environment make more and more tourists back to the forests for tourism. When introducing the rich resources of forest tourism , the relationships between forest tourism and culture , ecological tourism and sustainable development were analyzed .It is suggested that the forest tourism in China should be developed with plan and care on the basis of the effective protection of environment .[ Ch , 10 ref .]
A comparative study of ways to mediate forest ownership dispute
CHEN Yong-fu, CHENG Yun-hang, LI Lan-ying, CHEN Kang-ming
2004, 21(2): 198-202.
[Abstract](1162) [PDF](206)
Abstract:
There are three common ways to mediate forest ownership dispute , namely , negotiation , administrative ruling and judicial arbitration .They apply to different conditions .Negotiation is based on the condition that the forest ownership dispute is not caused by unilateral illegal behaviors and parties concerned are willing to negotiate and respect facts .The application of administrative ruling is on the condition that the dispute cant be settled by negotiation or hasnt been tried by court .Judicial arbitration is applied only after the procedure of administrative ruling or by submitting the case to the court within the fixed time .Negotiation can facilitate both the abidance and enforcement of the agreement , and the social unity and stability .However , the deficiency of this method lies in the longer mediation and much cost of finance and materials .Efficient administrative ruling can effectively settle the forest ownership dispute in time and control the case of unreasonable dispute .However , the performing effect of this method is not good because it is likely to bring forth antagonism between the parties concemed .Although judicial arbitration is fair and just and with the least consumption of labor , money and material , the enforcement of the arbitration cannot be guaranteed .According to the actual conditions in Zhejiang Province and from the perspectives of management and settlement mechanisms , policies and laws , the specific measures in properly applying these three mediating ways are put forward .[ Ch , 2 tab .4 ref .]
Evaluation of main production factors of profitable agriculture in the mountain areas of Zhejiang
JIANG Chun-qian, XU Xiu-ying, WUWei-guang, ZHAO Xia-wei, WANG Yu-ping
2004, 21(2): 203-208.
[Abstract](1206) [PDF](142)
Abstract:
Developing profitable agriculture is a fundamental approach to increase farmers income .The level of profitable agriculture development depends on the development of production factors to a great extent .The development conditions as well as deficiencies of three main production factors including capital , technology , and information were studied .The main deficiencies were as follows : (1)The capital input into agriculture from government and financial sectors doedid not match the contribution that agriculture has made , and the farmers are short of enough capital to develop agriculture .(2)The outlay for agriculture research and development was not sufficient and the reforms of technique promotion systems and institution operation are delayed .(3)The information network was not perfect ;the farmers depended on the traditional channels to collect relevant information .Based on the above limitations , the followings countermeasures to improve profitable agriculture development were put forward :(1)Increase governments and financial sectorsinvestment in agriculture and enhance farmers capacity to invest in agriculture field .(2)Establish a multiple investment system for agriculture research and development , in which government still shall play a leading role ;gradually set up a perfect agriculture technique promotion system and its operation mechanism which is fit for the market-oriented economy system.(3)Build agriculture information release channels and enhance the construction of agriculture information network .[ Ch , 2 tab .12 ref .]
Discussion about the disclosure of forestry accounting information
YANG Li-xia, SHI Dao-jin, FENG Ying-chun, WANG Yong-hong, ZHANG Fa-ping
2004, 21(2): 209-215.
[Abstract](1160) [PDF](223)
Abstract:
By revealing the limitations in current forestry accounting information disclosure and analyzing the necessity of improving forestry accounting information disclosure , the construction of the model of forestry accounting information disclosure in China was studied .The model consisted of the following items :(1)general principles of forestry accounting information disclosure ;(2) qualitative characteristics of forestry accounting information disclosure ;(3)contents of forestry accounting information disclosure ;(4)the way to disclose forestry accounting information .General principles included social principle , full disclosure principle , flexibility principle and costbenefit principle .Qualitative characteristics are composed of relevance , reliability , comparability , understandability and materiality .The contents of disclosure included forest resources assets , environmental cost , environmental revenue and environmental profit .The way of disclosure should combine financial report and environmental report to disclose truly and effectively the information of forestry ecologic benefit and social benefit to social masses and persons who are concerned .[ Ch , 10 ref .]
Indices analiysis of forestry journals in SCI-E web and the distribution of papers from China
FANGYong-cai, WU Guang-hao, ZHANG Jun-fei
2004, 21(2): 216-221.
[Abstract](916) [PDF](181)
Abstract:
Using the data in the 2002 edition of the ISI Journal Citation Reports , forestry journals indexed by SCI were summarized .The main indices of journals in forestry subject were compared with the mean value of indices of journals included in JCR .The results showed that the indices of journals in forestry subject were significantly lower than the average ones of JCR 2002 .For example , the number of papers in each forestry journal and cited frequency was 82.0 %and 61.9 % fewer than those in JCR 2002 respectively .The mean value of influential factors of the former was about 50 %fewer than the latter .A statistic analysis of the Chinese papers in forestry journals included in SCI in recent three years was conducted .The 102 papers written or co-written by Chinese researchers included in SCI forestry journals were published in 21 journals from 10 countries .101 papers were cited less than 10 times , accounting for 99 %.Paper writers from universities and colleges , China Academy of Sciences , academy of forestry and other institutions account for 54.9 %, 28.4 %, 12.7 % and 3.9 % respectively .Suggestions on the scientific evaluation of forestry in China on the basis of SCI are put forward .[ Ch , 1 fig .7 tab .5 ref .]
Discussion
Automatically obtaining of apearance features and computer-aided plant classification and identification QI Heng-nian
QI Heng-nian
2004, 21(2): 222-227.
[Abstract](1482) [PDF](249)
Abstract:
Classification and identification of plant are the groundwork for research on botany and management of forestry .Applying modern numerical taxonomy to plants is mostly based on the visible characteristics .The result is derived from the clustering analysis of many values of some visible characteristics .The traditional way of collecting the data manually is not so efficient .Since the visible characteristics are involved in the digital image of the plant or its local parts , image-processing technology can do the work automatically and efficiently .The focus here is how to obtain the characteristics automatically .On the basis of related researches such as computer-aided plantidentification model based on leaf characteristics and extracted sawtooth feature of leaf edge , a system scheme on plant classification and identification is developed .Then the feasibilities of technologies are also analyzed .[ Ch , 5 fig .19 ref .]
Problems and solutions in the implementation of forest resources dynamic information system at the county level
CAI Liang-liang, CAI Xia, ZHU Hong-wei
2004, 21(2): 228-230.
[Abstract](1390) [PDF](180)
Abstract:
The implementation of forest resources dynamic information system at the county level is an important way to manage the forest resources dynamically .However , the implementation of the system is still a weak tache in the collective forest areas in China .For better implementation of dynamic system of forest resources , the study expatiates on the significance of implementing the system , analyzes the problems such as weak consciousness of informatization and lack of information network institutions , puts forwardmeasures including establishing information network institutions , strengthening the training of implementing staff and collecting dynamic information scientifically .[ Ch , 1 fig .5 ref .]
Reviews
Techniques for transplanting mini color-leaved plantlets of Caladium bicolor grown in test-tube
ZHU Yu-qiu, ZENGYan-ru, XU Yuan, LI Mei-fei, YE Yi-qun
2004, 21(2): 231-234.
[Abstract](1122) [PDF](183)
Abstract:
The convenient and efficient techniques for transplanting mini color-leaved plantlets of Caladium bicolor grown in test-tube and the factors affecting its transplanting survival rate were studied .The results showed that it was unnecessary to acclimate plantlets before transplant .With main techniques for transplanting plantlets mastered and proper management , the survival rate was over 96 %.The best medium for transplant was the medium mixed with turf .Water the plantlets with enough water and keep the moisture for 10 -15 days in the plastic film shed .The plantlets should be kept with regular aeration , watering and control of pathogens .The optimal transplanting could be done when the plantlets were 3 -5 cm high and their roots were 0.5 -3.0 cm long .Suggestions on how to quicken the commercial production of plantlets were put forward .[ Ch , 4 tab .5 ref .]