2002 Vol. 15, No. 1
Progeny test was made with 13 hybrids of Eucalyptus urophylla × E.tereticornis, 10 hybrids of E. urophylla × E.camaldulensis, 1 hybrid of E. urophylla × (E. urophylla × E.tereticornis), 5 open pollinated families from the maternal trees of E. urophylla, and 1 open pollinated family from E. urophylla × E. tereticornis. Differences in height, diameter and volume were found at 0.01 significance level both among families and among replicates. Significant replicate among difference might be due to the uneven site condition to which hybrid was susceptible. Fifteen superior families and twelve superior hybrid individuals were selected out for further hybridization and clone test purposes.
This paper, based on methods of experiment technique and the data of collected from observation, the forest hydrology monthly dynamics of artificial mixed stands of coniferous and broad leaved trees and nature stands of evergreen broad leaved trees in Dagangshan district were studied, including soil moisture, surface runoff and total runoff. Some analysis results are as follows: (1)The maximum of soil moisture(5.18 mm) of artificial mixed stands of coniferous and broad leaved trees occurred in May, the minimum occurred in March; the distribute change of moisture in the depth is not obviously. (2)The surface runoff monthly change is greatly, and one off rainfall obviously affects soil moisture (R2 =0.939 5). (3)Compared with artificial mixed stands of coniferous and broad leaved trees, nature stands of evergreen broad leved trees had good effect of prevention of water and soil erosion and function of water conservation.
The experiments conducted on 3 isolates of P.solanacearum and 7 Casurina clones revealed that the adsorption of bacterial isolates to the host root surfaces differed significantly, a negative correlation between the adsorption amount and the pathogenicity existed; The propagation of 3 isolates within the roots also varied greatly, and a strongly positive correlation existed between the propagation amount and pathogenicity. The pretreated Casuarina ramets with LPS sharply reduced the adsorption of subsequently inoculated bacteria by 58.5% 97.3%, but EPS pretreated ramets did not show any apparent change. The bactcrial cells free of both EPS and LPS lost their adsorption amount by 63.3% 74.2%in comparison to the intact bacteria. However, the EPS free only bacteria slightly increased their adsorption up to 19.1%. Electrophoresis pattern of 3 isolates through SDS PAGE also showed difference with a special Rf=0.35 band occurred for the most virulent isolate 601B. It is concluded that the pathogenicity of P. solanaearum to Casuarina is associated with its adsorption amount on the host root surfaces and especially the rapid propagation capacity inside the roots. LPS plays a role of bacterial cognon in the recognition between the pathogen and host while EPS covers or inhibites this process of LPS. Both LPS and EPS are all important factors that affect the pathogenicity of P. solanacearum.
The variation in wood properties and the differences between juvenile wood and mature wood of Masson Pine(Pinus massoniana) plantation from Guangxi were studied. The results are as follows: The boundary between juvenile and mature wood was delimited at the age of 14～16 year. The radial variation patterns of the anatomical properties from pith to bark are: the ratio of ray tissues, ratio of resin canal, cell walls percentage, lumen diameter, wall thickness of tracheid, tracheid diameter, tracheid length, ratio of wall to lumen (latewood) increase with the increase of growth ring, while ratio of tracheid and ratio of lumen to diameter decrease with the increase of growth ring. Most parameters of the anatomical properties of mature wood are higher than that of the juvenile wood with significance level shown in ratio of resin canal, cell walls percentage, wall thickness of tracheid, tracheid diameter, tracheid length. All of the physical and mechanical properties of mature wood are higher than that of juvenile wood significantly. Analysis of relationship showed that the ratio of ray tissues, ratio of resin canal, rate of cell wall, tracheid length were positively correlated to wood density with significance level. The MOR, MOE, and crushing strength were positively correlated to wood density significantly in juvenile and mature wood.
Under low temperature stress, the contents of the soluble sugar, the soluble protein and the free proline changed significantly. And there are significant correlation between them and the treatment temperature. The specific activity of SOD decreased at first and then increased in the whole. The content of MDA firstly increased, then decreased, and finally increased again. The cold resistance of seedlings of A. mangium was increased by pretreatment with abscisic acid. The result showed that the pretreatment of either 10-4 mol·L-1 ABA foR24 hours or 10-5 mol·L-1 ABA for 36 hours was the optimum treatments to improve plant cold resistance.
Photosynthesis of half year seedlings of pagoda tree and walnut were determined after different time treatment of 50,100 and 200 mmol·L-1 NaCl. Results showed that photosynthetic rate of walnut decreased distinctly and decreased more when the salinity increased and treatment time lengthened. Photosynthetic rate of pagoda tree increased after salt treatment and increment was less when treatment time lengthened. The content of chlorophyll a and b of both tree species changed little during 24 stressed days of 200 mmol·L-1 NaCl with the exception of ratio of chlorophyll a to b reduction in walnut. The content of xanthophyll in pagoda tree increased firstly and then kept the level as that of the control. In contrast to pagoda tree, the content of xanthophyll in walnut decreased obviously. Main difference between pagoda tree and walnut in CO2 response curves was that photorespiratory rate in pagoda tree decreased to 43.7% of the control with 71.6% of the control increase in walnut and that CO2 compensation point decreased 13.58% in pagoda tree with 194.15% increase in walnut both compared to the control. Light response curves revealed that dark respiratory rate of pagoda tree was 3 folds more than that of the control while that of walnut decreased to 65.28% of the control. And photo inhibition occurred in salt stressed walnut.
To analyze the adaptation of Hippophae rhamnoides L. to water condition of the semiarid loess hilly region, water physiological and ecological characteristics of Hippophae rhamnoides L. and drought resistance were studied in 1998. The following results are obtained: (1) Hippophae rhamnoides L. forms the way of drought resistance of dry hardiness and keeping out drought to adapt the habitat of semiarid loess hilly region. In dry season, Hippophae rhamnoides L. shows stronger drought resistance, leaves of Hippophae rhamnoides L. can keep higher relative water content, weak transpiration intensity, low leaf water potential, big critical saturation deficiency, higher bound water content and bigger ratio of bound water to free water. (2) Photosynthetic rate of Hippophae rhamnoides L. has obviously diurnal variation,first peak assumed at 10:00 12:00, the second at 14:00 15:00. Photosynthetic rate has significant correlation with environmental factors (temperature, relative humidity and photosynthetic active radiation), and the coefficient was 0.846 6 0.935 1, of which photosynthetic active radiation has the biggest effect on photosynthetic rate, followed by temperature and relative humidity. Photosynthetic rate has utterly significant correlation with stomatal conductance and intercellular CO2 concentration, and the coefficient is 0.985 2 0.985 6.(3)Transpiration rate and stomatal conductance have a similar diurnal variation, both exhibiting a single peak pattern in May and July, and bimodal pattern in June? August and September. In growing season, May through September, the maximum of transpiration occurs in July, lower value in May and September; Transpiration rate in May (0.39 g·g-1 ·h -1) was just 41.93% of that in July (0.93g·g-1 ·h-1). The result indicates that precipitation primarily could meet the need of growth of Hippophae rhamnoides L. to the environmental condition of Ansai loess hilly region, Hippophae rhamnoides L. can be selected as pioneer species for planting in this region. These provide scientific basic for drought resistant forestation of Hippophae rhamnoides L., introducing fine variety, breeding and improving management.
Stand biomass and productivity of five stands with different ages from young growth to mature forest had been studied by the methods of diameter class sample tree in which we substitute space distribution of stand for progress of time. The results showed that tree biomass was allocated to each organ according to definite percentage, the percentages were not relative to diameter class, but relative to stand age. With stand age increasing, biomass of stand average tree and each organ increase. The annual growth speed of biomass is the biggest at 18 22 year for stand average tree, but the biggest at 12 18 year for the stand. With stand age increasing, the percentage(above 48%) of stem biomass increases, but that of branch, leaf and bark are on the contrary. When time is shorter than 18 year, with stand age increasing, the percentage of root decreases, then it tends to be stable. The percentage orders of each organ biomass are stembranchrootbarkleaf. Stand(stem) tree stratum biomass and net productivity of stands at the age of 8, 12, 18, 22, 30 are 33.94(16.39),89.94(52.60),204.51(134.52), 223.71 (150.96),234.12(158.94) t·hm-2 and 6.24(2.05),11.14(4.38),15.63(7.47),14.07 (6.86),11.93(5.30) t·hm-1 ·a-1 individually. The diameter class distribution laws of biomass are similar to that of tree, many of them are left offset prior to hail mature forest, since then it tends to right side, its peak is moved 1 2 diameter class to right. Pulewood stand should be cut by 18 years old.
The technique of multiplicative and rooting ratio in vitro of 30 plus tree of Acacia mangium was studied. There are great difference among clones in multiplication and rooting at the early stage of tissue culture. The results show that 30 clones can be divided into 3 multiplicative types, i.e. fast, middle and slow multiplicative types. The fast one can reach to high monthly multiplicative ratio (2.18 times per month) after 13 to 15 months'introduction while it has good rooting property with 91.0 per cent. But the middle and slow one can't get the high monthly multiplicative ratio till they got 18 to 22 months' introduction.
There are three parts in this research, including the effects of different planting density, different thinning intensity and planting density thinning on the growth of Chinese fir stand. (1)Planting density experiment consist of five density treatments:A(1 666 trees·hm-2), B(3 333 trees·hm-2),C(5 000 trees·hm-2), D(6 666 trees·hm-2) and E(10 000 tress·hm-2). The result of experiment shows that the dominant height, average height and diameter at breast height (DBH)of stands increases with the increase of stand age, and decreases with the increase of stand density. The dominant height after age 9, average height after age 6 and DBH after age 5 have evident differences among different stand densities. Stand volume increase with the increase of stand age, and it reaches evident difference from age 5 to 7 among different densities, but it only has remarkable differences between A and E or D from age 8 to 18. The tree height under first branch increases with the increase of stand density and trees age, the difference among C,D and E are not obvious after age 12. The crown diameter decreases with the increase of stand density, and increases with the increase of trees age, the differences among different stand densities decreases after age 9 10. (2)The primary planting density for the thinning test of planting density is same as the planting density experiment, thinning methods are that C is reduced to D and D is reduced to E after thinning. The results shows that at same site index class, comparing the unthinned stand with the thinned stand which keeps the same density with the unthinned stand after thinned, their average height and dominant height has no evident difference, but the standing tree volume of thinned stand is lower than that of unthinnned stand, the total volume (standing tree volume + thinned tree volume) of thinned stand is higher than that of unthinned stand, the ratio of total volume of thinned stand with high primary density to unthinned stand is higher than that of thinned stand with low primary density to unthinned stand. At the same primary density, the ratio of volume thinned stand to unthinned stand at the high site index class is higher than that at the low site index class.
The controlled hybridization between a female Populus deltoides Marsh,'55/65' and 5 provenance (10 individuals each provenance) of the male P. cathayana Rehd. produced the hybridization system with multi level variations for breeding. The 7 leaf traits, including leaf length, leaf width, ratio of leaf length to width, petiole length, ratio of petiole length to main vein, angle between main and the second leaf vein, leaf base of the parents and F 1 hybrid were analysized. The analysis of variance showed that significant difference of leaf traits existed among provenances and among individuals within provenances of P. cathayana. Several leaf traits of F 1 hybrid also showed significant difference among provenances, among families within provenances and among clones within families. Comparison between leaf traits of parent and those of F 1 hybrid suggested that the male parent has more effects on leaf traits of F 1 hybrid than of female parent. No significant difference of plant surviving existed among F 1 clones. The significant difference of 1,2,3 year old growth among F 1 clones showed that the variation of male parents brought notable effect on growth of F 1 clones. Correlation between leaf and growth of F 1 clones was not significant. These results of analysis will provide more base information about multiple level variations on such traits as growth and wood properties for poplar breeding in future.
The accumulation and distribution of nutrient in Fokienia hodginsii plantation were studied. The results showed: The content of N, P, K in the needle gradually decreased from the bottom to the top along the continual slope, so did the accumulation of nutrients. Conversely, the content of Ca, Mg, Fe, Cu, Zn in the needle increased along the continual slope. The content of nutrient in needle was different with the stand ages. The content of N, P decrease, the content of Ca, Mg increased, and the content of K was relatively stable with the growth of tree. In the 10 and 20 age stands, the sequence of the nutrient accumulation in the different parts of the tree was needleroottrunkbranchbark, in the 30 age stand, however, this sequence was roottrunkneedlebranchbark. The total amount of nutrient accumulation was 30 year old20 year old10 year old. The utilization efficiency increased with the tree growth. In the different period of tree growth, there were differences on accumulation and distribution of nutrient.
The quantitative distribution of soil microorganism of different protective forest types in rocky sub tropical coast is studied.By means of mathematical analysis,the relationship of soil microorganism with enzyme activity,physical and chemical property is discussed.The results are as follows:①There is significant correlation among the three types of microorganisms.Major population is bacteria,followed by actinomycete,the least one is fungi.But the percentage of fungi is much higher than that in silting coastal areas.②The quantity of soil microorganisms in different forest types is quite different.There are more soil microorganisms in no timber forest,whereas the number is less in mature forest of Pinus massoniana and Myrica rubra.③There is a correlation between soil microorganisms and enzymes, but the coefficients are low. ④There is close correlation between soil microorganism and physical,chemical property.At last,some relative problems are discussed.
The Mycorrhizas in Dendrobium candidum, D. nobile Lindl. and D. moniliforme are composed by velamen, cortex, stele under the microscope. The germ is living and growing inside the cell of cortex as a peloton. According to the analysis for both mycorrhizas organ and nonmycorrhizas one, the contents of N,P,K in the former are about 2 5 times more than in the later, but the contents of microelment, such as Cu, Fe, Mn, Ca, Mg etc.
Eight exotic species were tested in terms of drought resistance in Yuanmou dry hot valley. The order of water use efficiency (WUE) was:Eucalyptus exsertaE. camaldulensisE.citriodoraAcacia holosericeaA. cunningA. crassicarpaA. auriculiformisA.mangium. The higher WUE implies the better the drought resistance and the adaptation to dry hot environment. The anatomical structure observation showed that the characteristics of the adaptation xeromorphic structure of eight species in dry hot valley were: deep main roots, developed lateral roots, thick leaves, well developed palisade tissue and degenerated spongy tissue, well developed water storing tissue, isolateral leaf were important characteristics of xeromorphic structure. The survival mechanism of Eucalyptus with high transpiration rate in dry hot valley is for their deep root system that can actively supply water to the leaves. The well developed root system and high water holding capacity of leaves enable Acacia to adapt the dry hot environment.
There is a long history for human to use insects as food. As one kind of food, edible insect has the character of vast in species, population and quantity. They are also easy to be fed. The results of research showed that edible insect contains various nutrient elements, such as protein, amino acids, fat, fatty acid, vitamins and mineral elements. So edible insect has important value for human and worth to be developed and utilized. The ways to utilize edible insect are various.
Study on the sampling technique of Pineus armandicola and the relationship between the occurrence of it and environmental factors was conducted in 222 Forest Farm, Dongchuan, Yunnan Province. It was found that the best sampling site is the middle east of the crown canopy. The best sampling number is calculated as the model: N=127.25/ +1.87. Using Latin square orthogonal design, the relationship between the occurrence of Pineus armandicola and environmental factors was revealed. Among the investigated environmental elements, the most important key factor to influence the variance of population density is the tending status of the woods. Other key factors are successively slope direction, elevation and canopy density. Advice on how to control Pineus armandicola is also given.
Adventitious buds were induced by using tender buds emblic (Phyllanthus emblica L.) as explants with MS medium contained different concentration of BA and KT, GA 3,NAA or IAA, of which MS medium combined with 0.5 mg·L-1 of BA and 0.1 mg·L-1 of NAA is suitable for adventitious buds inducement, the rate of differentiation reached more than 90%. MS medium with 0.1 mg·L-1 of BA and 0.1 mg·L-1 of NAA is suitable for the growth of shoots, and 2 3 adventitious buds were regenerated in base. But rooting rate reached only about 30% by using 1/2 MS with 0.25 mg·L-1 of NAA or with 0.25 mg·L-1 of NAA and 0.25 mg·L-1 of IBA.