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Differences in Seedling and sapling Densities and Species Composition between Canopy Gaps and Forest Understories in a Subtropical Forest in Bangladesh

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Journal of Resources and Ecology 2025年第1期16卷 105-114页

作者： Tarit Kumar BAUL Anwarul Islam CHOWDHURY Md Jamal UDDIN Mohammad Kamrul HASAN Tapan Kumar NATH Lars Holger SCHMIDT Institute of Forestry and Environmental Sciences University of ChittagongChittagong 4331Bangladesh Faculty of Science Forestry and TechnologySchool of Forest SciencesUniversity of Eastern FinlandJoensuu 80101Finland Department of Agricultural and Forest Sciences and Engineering University of LleidaLleida 25001Spain Natural Resources Institute Finland(Luke) Helsinki 00790Finland Faculty of Science and Engineering University of Nottingham MalaysiaJalan Broga 43500Malaysia Department of Geoscience and Natural Resource Management University of CopenhagenFrederiksberg C 1958Denmark

Canopy openings have a vital role in forest structure,regeneration,and plant *** this study,we investigated and compared the species composition and densities of seedlings and saplings between canopy gaps(openings)and forest understories(in dense canopies)in a sub-tropical forest of *** objectively identified 42 canopy openings between transect lines and 42 main plots in dense canopies,sampled for regeneration and young tree *** the regeneration study,we placed 2 m×2 m four subplots in each canopy opening and the main plot of dense canopy,thus making a total of 336 *** species diversity of seedlings,saplings,and trees were significantly(P≤0.05)higher in the dense canopy than in the canopy ***,most dominant and frequent regenerating species such as Diospyros pilosula,Garcinia cowa,Brownlowia elata,and Lithocarpus polystachya were common in both dense canopy and openings,the canopy openings had the highest Importance Value Index,suggesting the significance of gap dynamics in the dominance of native floral *** dense canopy played an important role in forest compositions because 12 regenerating species,including Stereospermum suaveolens and Diospyros montana,were not found in the canopy openings,implying that rain forests must maintain a high canopy cover for regeneration.

关键词： canopy opening disturbance forest dynamics native flora seedling sapling

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Indexes of Tree Structure of Cylindrical Pear Orchards at the sapling Stage

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Agricultural Biotechnology 2019年第3期8卷 145-146页

作者： Shuwei WEI Shaomin WANG Ran DONG Xiaochang DONG Shandong Institute of Pomology

The reasonable tree and population structure parameters of various cylindrical pear orchards were *** results showed that for 3-year-old ‘Xinli No.7’,the tree height was 3.48 m,and the trunk height was 63 cm;there were 63 branches per plant,which was equivalent to 19 971 branches per 667 m^2;the leaf area index was *** the 3-year-old ‘Xueqing’,the tree height was 3.03 m,and the trunk height was 74 cm;the number of branches per plant was 57,which was equivalent to 18 069 branches per 667 m^2;the leaf area index was *** cylindrical trees of the two varieties had the following characteristics: the canopy structure was tight;the branches were equally distributed,and the number of medium branches and short branches accounted for more than 60% of the total number of branches of the whole plant.

关键词： Pear sapling Cylindrical

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Photosynthesis and Water Use Efficiency of Platycladus Orientalis and Robinia Pseudoacacia saplings under Steady Soil Water Stress during Different Stages of Their Annual Growth Period

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Journal of Integrative Plant Biology 2007年第10期49卷 1470-1477页

作者： Ming-Chun Wang Jin-Xin Wang Qing-Hua Shi Jin-Song Zhang College of Forestry Northwest A&F University Yangling Shaanxi China712100 College of Resources and Environment Northwest A&F University Yangling Shaanxi China712100 Research Institute of Forestry Chinese Academy of Forestry Beijing China100091

A simulated drought experiment was conducted in a rain-free shed to test the physiological response of Platycladus orientalis and Robinia pseudoacacia saplings to steady soil water stress during different stages. The five soil water treatments were： 100%, 87.84%, 70%, 52.16% and 40% of field capacity. The results showed that the net photosynthetic rate of R. pseudoacacia decreased as soil water potential decreased in the range between -0.041 MPa and -0.292 MPa. The threshold value at which the net photosynthetic rate changed significantly was -0.12 MPa. The relationship between net photosynthetic rate of P. orientalis and soil water potential could be described as a quadratic parabola in the range between -0.041 MPa and -0.648 MPa. Analysis of variance showed significant differences in the net photosynthetic rate of P. orientalis between soil water potentials of -0.061 MPa ~, -0.648 MPa. Average water use efficiency （WUE） increased as soil water potential decreased, but the influence mechanism of soil water stress on leaf WUE and photosynthetic rate for the two species were different evidently.

关键词： growth stages photosynthesis Platycladus onentalis Robinia pseudoacacia sapling steady water stress water use efficiency.

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Effect of Gamma Irradiation Doses on Morphological and Biochemical Attributes of Grape saplings

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Agricultural Sciences 2015年第5期6卷 505-512页

作者： A. F. M. Saiful Islam M. Muzahedul Islam Md. Mehedi Hasan Md. Mehedi Hasan Department of Crop Botany & Tea Production Technology Sylhet Agricultural University Sylhet Bangladesh

The demand of grape in Bangladesh is fulfilled through import from foreign countries. The fruits of local cultivars of grapes are sour and seeded. Development of seedless grape varieties having increased sweetness, higher yield with better nutritional quality is necessary to reduce the import dependency. The present research activities are the part of a grape improvement project. A pot experiment was conducted at the Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh, during June to November 2011 to determine the suitable gamma irradiation doses on growth, leaf area and biochemical characters of grape saplings. Three vegetative bud stages viz. bud initiation stage, 4-leaf stage and 8-leaf stage, and four doses of gamma irradiation viz. 0, 5, 10, and 15 Gy were used as treatments. The experiment was laid out in a Randomized Complete Block Design with four replications. Different irradiation doses and vegetative bud stages showed significant variations in respect of plant growth characters, leaf area, soluble protein and total sugar content. Interaction effects also had significant variations on most of the parameters studied. Higher doses of gamma irradiation had showed detrimental effect on grape saplings. Generally, increased in irradiation doses showed decreased and detrimental effects on most of the parameters under study. Maximum numbers and length of roots, total dry matter, leaf area and chlorophyll-a and chlorophyll-b content were found at 5 Gy irradiation dose. Total soluble protein and sugar content of leaf were found maximum at no irradiation and 15 Gy, respectively. Higher number of roots and length, total dry matter, leaf area, chlorophyll-a, and b and soluble protein content of leaf were observed at bud initiation stage while 8-leaf stage showed maximum total sugar of leaf. In the combined effect of gamma irradiation and vegetative bud stages, all parameters showed best results in 5 Gy with bud initiation stage except total sugar content of

关键词： Grape sapling Gamma Irradiation Morphological and Biochemical Parameters Leaf Area Soluble Protein

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Growth Analysis of Nyssa yunnanensis saplings

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Agricultural Science & Technology 2016年第4期17卷 880-882,886页

作者：王兰新郭贤明宗春淼西双版纳国家级自然保护区科研所云南景洪666100

The growth of Nyssa yunnanensis saplings in Guanping area was monitored in 2011, 2013 and 2015. The results showed that the average basal diameter growth rate during 2013-2015 was higher than that during 2011-2013, and that during 2009-2011 was lowest; the average height growth rates in the durations of 2011-2013 and 2013-2015 were basically the same, and that during 2009-2011 was relatively slow; the growth of diameter at breast height（DBH） in the duration of 2013-2015 was significantly higher than that in the duration of 2011-2013. Comprehensive and better nature-returning work, as well as long-term and stable funding, is required for the protection of Nyssa yunnanensis.

关键词： Nyssa yunnanensis sapling Growth Xishuangbanna

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Tree Planting

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天天爱英语 2019年第3期 38-38页

作者：于浩洋冯会丽(指导) 山东省东营市春晖小学五(4)班不详

Our school organized a tree planting activity on Thursday *** weather was fine that *** came to a desolate *** first thing I did when I got there was to dig a hole for my sapling.

关键词： school tree sapling

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