Induction of acropetal (14)C-photosynthate transport and radial growth by indole-3-acetic acid in Pinus sylvestris shoots

The relationship between radial growth and assimilate movement was determined in one-year-old Pinus sylvestris (L.) cuttings collected during the dormant period and reactivated for 1-27 days under environmental conditions favorable for growth. The cuttings were either left with buds intact, defoliated along the distal 8 cm, or debudded and treated apically with 0 or 1 mg g(-1) indole-3-acetic acid (IAA) in lanolin. Radial growth was measured as tracheid production and bark radial width. The distribution of (14)C-photosynthate 1 or 5 days after exposure to (14)CO(2) was used to indicate assimilate movement. Debudding inhibited tracheid production and decreased acropetal (14)C-photosynthate transport, whereas applying IAA to debudded cuttings promoted both these processes and, in addition, induced vigorous callus growth within the bark immediately below the application point. Distal defoliation markedly increased the amount of (14)C-photosynthate transported toward the apex without altering how debudding and exogenous IAA affected tracheid production and the distribution of (14)C-photosynthate. The production of tracheids induced by apically applied IAA in debudded and distally defoliated cuttings increased progressively in material collected on September 9, October 14 and November 24, whereas bark radial width and acropetal (14)C-photosynthate movement increased only between the first two collection dates. Ringing midway between the IAA source and the bottom of the distally defoliated region with a lanolin mixture of 10 mg g(-1)N-1-naphthylphthalamic acid (NPA), 1 mg g(-1) methyl-2-chloro-9-hydroxy-fluorene-9-carboxylic acid (CF) or 10 mg g(-1) phenylacetic acid (PAA) reduced radial growth and [1-(14)C]IAA transport below the ring and locally promoted radial growth and accumulated radioactivity above. (14)C-Photosynthate transport into the region above the ring either was not altered (CF, PAA) or was increased (NPA). The results indicate that apically applied IAA induces the acropetal movement of (14)C-photosynthate in debudded P. sylvestris shoots by locally promoting activity correlated with tracheid and callus production rather than by affecting radial growth or phloem transport processes, or both, at a distance below the IAA source.     

Gravimorphism in current-year shoots of Abies balsamea: involvement of compensatory growth, indole-3-acetic acid transport and compression wood formation

We investigated the cause of gravimorphic growth inhibition in current-year shoots of balsam fir (Abies balsamea (L.) Mill.) seedlings displaced from their normal orientation in the gravitational field. Tilting the main stem of seedlings decreased shoot elongation, cambial growth as measured by tracheid production, and leaf dry weight of the terminal shoot and the lateral shoots on the lower side of the tilted stem. Removing either the terminal shoot or all lateral shoots induced compensatory growth in the remaining shoots, but did not reduce the inhibitory effect of tilting on shoot growth. Bending the apical part of a tilted main stem to restore it to the vertical did not fully reverse the inhibition of terminal shoot growth caused by stem tilting. Stem tilting inhibited cambial activity at the base of decapitated terminal shoots treated apically with indole-3-acetic acid (IAA) and decreased the basipetal transport of a [1-(14)C]-IAA pulse. Stem tilting also induced compression wood formation on the lower side of the tilted stem. Compression wood formation was associated with increases in cambial activity and stem respiration. Stem tilting did not affect either the net photosynthetic rate in 1-year-old leaves or the xylem water potential in current-year lateral shoots. These results support the hypothesis that gravimorphic growth inhibition in a current-year shoot on a tilted stem involves reductions in (1) the shoot's capacity to export IAA, and hence to mobilize photoassimilates, and (2) the supply of photoassimilates available for import by the shoot, as a result of increased cambial sink activity associated with compression wood formation outside that shoot.     

The relationship between crown size and ring width in Pinus sylvestris L. stems: dependence on indole-3-acetic acid, carbohydrates and nitrogen in the cambial region

Indole-3-acetic acid (IAA), carbohydrates, total nitrogen and amino acids in the cambial region and bark were measured at the top (10-year-old internode) and bottom (1.3 m) of the main stem of 50-year-old Pinus sylvestris L. trees, having different rates and longitudinal gradients of annual ring width formation. The trees were sampled during the most active period of wood production (June 23, July 15) and at the end of this period (August 23). Trees with a small crown and relatively slow growth rate (S-trees) were compared with trees in the same stand that had a large crown and fast growth rate (F-trees) as a result of thinning and fertilization. The effect of bottom pruning fast-growing trees (pruned F-trees) was also investigated. The F-trees had greater wood production than the S-trees at both the stem top and bottom. The difference was larger at the stem bottom, thus the relative decrease in ring width down the stem was steeper in the S-trees. The amount of sucrose and IAA per cm(2) in cambial region tissues was higher in F-trees than in S-trees. However, the differences in annual ring width between treatments and within trees were not reflected in the concentrations (expressed per gram fresh weight) of these substances, measured either in differentiating xylem, the cambium plus phloem, or in the cambial region as a whole. The concentrations of total nitrogen and amino acids were slightly higher in the F-trees than in the S-trees. Pruning the F-trees reduced wood production, particularly at the stem bottom, inhibited the springtime increase in starch, and decreased the amounts of sucrose and IAA per cm(2) in the cambial region. However, it was evident that the concentrations of sucrose, IAA, amino acid and nitrogen in the cambial region were not related to ring width. During June and July, the concentrations of these substances were generally higher at the stem bottom in the pruned F-trees than in the F-trees. The results provide evidence that it is the activity of the cambium rather than the availability of carbohydrates that determines the allocation of wood production along the tree stem. The results also indicate that tracheid production is not directly related to the IAA concentration in the cambial region.     

Boron and ectomycorrhizal influences on indole-3-acetic acid levels and indole-3-acetic acid oxidase and peroxidase activities of Pinus echinata Mill. roots

The level of indole-3-acetic acid (IAA) in shortleaf pine (Pinus echinata Mill.) roots was increased by inoculation with the ectomycorrhizal fungus Pisolithus tinctorius (Pers.) Coker and Couch. Indole-3-acetic acid oxidase activity was also increased suggesting that the increased level of IAA was the result of increased synthesis. Boron fertilization reduced IAA levels in roots inoculated with P. tinctorius but not in noninoculated roots.     

Laterally applied Ethrel causes local increases in radial growth and indole-3-acetic acid concentration in Abies balsamea shoots

The terminal (1-year-old) shoot of quiescent, two-year-old balsam fir (Abies balsamea (L.) Mill.) seedlings was ringed with lanolin containing 0, 1 or 10 mg g(-1) Ethrel, an ethylene-generating compound, and cultured for 6 weeks under environmental conditions favorable for growth. Bud break and the elongation of the current-year terminal shoot were monitored, and the subjacent previous-year terminal shoot that had been treated with Ethrel was harvested to measure stem radial growth by microscopy, shoot ethylene evolution by gas chromatography, and cambial region indole-3-acetic acid (IAA) concentration by combined gas chromatography-mass spectrometry. Compared with the lanolin controls, Ethrel at 1 and 10 mg g(-1) did not affect bud break or longitudinal growth, but stimulated tracheid production and bark increment up to about 2-fold at the application site, though not above or below it. In addition, the 1 and 10 mg g(-1) Ethrel treatments increased the cambial region IAA concentration about 3-fold and the evolution of ethylene at least 40-fold at the application site, compared with unwounded portions of both treated and control shoots. The 10 mg g(-1) Ethrel treatment also stimulated ethylene evolution about 10-fold, both above and below the application site. However, this stimulation was not associated with an elevation in cambial region IAA concentration. Similarly, the lanolin control treatment increased ethylene evolution at the application site about 10-fold, without affecting the cambial region IAA concentration. Our results suggest that the localized stimulation of radial growth in woody shoots ringed with Ethrel is mediated by an increase in IAA concentration, which in turn is induced by a threshold, abnormally high concentration of Ethrel-derived ethylene.     

Interaction between indole-3-acetic acid and ethylene in the control of tracheid production in detached shoots of Abies balsamea

We investigated the interaction between indole-3-acetic acid (IAA) and ethylene in the regulation of the seasonal periodicity of tracheid production in 1-year-old balsam fir (Abies balsamea (L.) Mill.) cuttings collected at different times during the dormant period. The cuttings were left with their buds intact or were debudded and treated either apically with IAA or 2-chloroethylphosphonic acid (Ethrel) in lanolin, laterally with IAA or Ethrel in lanolin, or basally with Ethrel, Co(2+) or Ag(+) in deionized water. The treated cuttings were then cultured for up to 5 weeks under controlled environment conditions favorable for cambial growth. No change in ethylene evolution was detected during the rest-quiescence transition, when IAA-induced tracheid production increased. The induction of cambial reactivation by IAA was associated with a rise in ethylene evolution, but there was no consistent relationship among IAA concentration, tracheid number and ethylene emission. Neither Ethrel, Co(2+) nor Ag(+) affected tracheid production when applied basally, except for 10 and 100 micro M Ethrel and 100 micro M Co(2+), which were inhibitory. In contrast, ethylene evolution was promoted by Ethrel and inhibited by Co(2+), whereas Ag(+) had no effect. Similarly, applying Ethrel apically or laterally increased ethylene evolution, but did not promote tracheid production except in the treatment in which 1 mg Ethrel g(-1) lanolin was applied laterally to cuttings treated apically with 0.1 mg IAA g(-1) lanolin, and in the treatment in which 10 mg Ethrel g(-1) lanolin was applied laterally to budded cuttings. We conclude that (1) ethylene evolution is not specifically associated with IAA-induced tracheid production, (2) ethylene does not mimic the promoting effect of IAA on tracheid production, and (3) ethylene can promote tracheid production, but only when its application results in a localized unphysiologically high concentration in the cambial region, which, in turn, induces an accumulation of IAA.     

Identification and quantitation of indole-3-acetic and abscisic acids in the cambial region of Quercus robur by combined gas chromatography-mass spectrometry

A technique is described for the rapid purification of indole-3-acetic acid (IAA) and abscisic acid (ABA) from small quantities of the basal trunk cambial region tissues of 34-year-old trees of Quercus robur L. Mass spectra of IAA and ABA obtained from the purified extracts provide the first reported unequivocal identification of endogenous IAA and ABA in the cambial region of a hardwood species. By use of the combined gas chromatography-mass spectrometry technique of multiple ion monitoring, with deuterated analogs as internal standards, it was shown that the levels of IAA in the cambial region tissues varied from ~1 to ~20 microg g(-1) and those of ABA from ~1 to ~5 microg g(-1) dry weight during the growing season. The high levels of IAA are similar to those found in the newly differentiating xylem tissues of softwoods.     

Dynamics of indole-3-acetic acid during germination of Picea abies seeds

High performance liquid chromatography and combined gas chromatography-mass spectrometry were used to identify indole-3-acetic acid (IAA) and indole-3-ethanol as endogenous constituents of germinating Norway spruce (Picea abies (L.) Karst.) seeds. Indole-3-methanol was tentatively identified by multiple ion monitoring. The free IAA content of the seeds rose from about 20 ng g(-1) to about 60 ng g(-1) (dry weight) during the first five days of germination and thereafter declined to around 20 ng g(-1). Indole-3-acetic acid released by alkaline hydrolysis, which was initially present at about 110 ng g(-1), decreased to 5-10 ng g(-1) during the first week of germination. The IAA content of seed lots differing in germination behavior was investigated. The findings are discussed in relation to the metabolism of IAA in conifer seeds.     

樟子松红斑病调查及防治

文章主要介绍了大兴安岭呼玛县金山林场樟子松母树林松针红斑病即松穴褥盘孢菌[Dothistroma PiniHulbary的诱发因素及其防治方法。     

Cold acclimation of Pinus contorta and Pinus sylvestris assessed by chlorophyll fluorescence

Needle samples of six provenances each of lodgepole pine (Pinus contorta Dougl. var. latifolia) and Scots pine (Pinus sylvestris L.), originating from latitudes 55 to 68 degrees N in western Canada and northern Sweden, were collected during the autumn and subjected to freezing temperatures in the range of -8 to -29 degrees C on three occasions in September and October. Needle injury was assessed by two different methods: visual assessment and chlorophyll a fluorescence. Chlorophyll a fluorescence data showed a highly significant correlation with the visual assessments of injury, indicating that the technique can be used as a simple, non-destructive and objective measure for rapid detection of freezing injury and for ranking of needle materials with respect to development of cold acclimation. The analyses showed that, during the autumn, lodgepole pine needles were more hardy and acclimated to low temperatures earlier than Scots pine needles.     

Potential for Biological Control of Botrytis cinerea in Pinus sylvestris Seedlings

Grey mould (Botrytis cinerea Pers.: Fr.) is the most common economically important fungal disease in Swedish forest nurseries. In tests in a growth room, foliage of predisposed (preinoculation incubation at 35°C for 4 days) Scots pine (Pinus sylvestris L.) seedlings was sprayed with suspensions containing Mycostop®, Binab® TF.WP or GlioMix® at concentrations of 0.5, 1 or 0.5 g l^?1, respectively, and/or conidia of B. cinerea (10⁶ spores ml^?1). Binab and GlioMix reduced grey mould in needles by 94 and 92%, respectively, and were as effective as the fungicide Euparen® M 50 WG, while Mycostop reduced disease by 51%. In one trial in a forest nursery, Mycostop, Binab and GlioMix, each applied two and four times during the growing season, suppressed spontaneous B. cinerea infections in needles of first year container-grown P. sylvestris seedlings by 16–57%, and were as effective as recommended fungicidal sprays. It was concluded that biological control has potential to effectively suppress grey mould in seedlings in forest nurseries.     

Metabolism of deuterium- and tritium-labeled gibberellins in cambial region tissues of Eucalyptus globulus stems

Deuterium- and tritium-labeled gibberellins (GAs) were applied to stems of 3-year-old Eucalyptus globulus Labill. saplings and 9-month-old potted seedlings. Cambial region tissues surrounding the application point were collected 6, 24 or 48 h later. Twenty-four hours after application of 5 &mgr;g of [(2)H(2)]GA(20), 7% of the cambial region GA(20) pool, 7% of the GA(1) pool and 58% of the GA(29) pool were labeled with deuterium based on selected ion monitoring of purified extracts subjected to gas chromatography-mass spectrometry. The relatively low percent dilution of endogenous GAs by [(2)H(2)]GAs suggests that the exogenous application of [(2)H(2)]GA(20) did not result in substrate overloading, indicating that these conversions probably occur naturally within cambial region tissues. Extracts from similar cambial region tissues fed tritium-labeled GAs were sequentially fractionated by SiO(2) partition chromatography, C(18) reversed phase HPLC and N(CH(3))(2) HPLC. The radioactivity profiles indicated metabolism of GA(20) to GA(1) and GA(29), GA(1) conversion to GA(8), GA(4) to GA(34) and GA(9) to GA(51). Gibberellins GA(34), GA(51) and GA(29) are C-2beta-hydroxylated catabolites of low biological activity, whereas GA(1) and GA(4) are probably effectors of growth in the Eucalyptus stem and shoot. Evidence for C-13 hydroxylation of GA(4) to GA(1), GA(9) to GA(4) or GA(9) to GA(20) in the stem was inconclusive. Thus, although GA(4) and GA(9) are native to cambial region tissues, GA(1) is probably not produced from them in significant quantities. We conclude that the early C-13-hydroxylation pathway; i.e., conversion of GA(19) to GA(20) to GA(1), is the major pathway of GA(1) biosynthesis.     

Timber quality and volume increment of advance growth and planted Pinus sylvestris

Timber quality and increment of Scots pines were analysed in two adjacent stands in northern Sweden. One stand originated from advance growth, and one from planted seedlings. Height increment of advance growth that was higher than 1.3 m when released was slow compared with advance growth lower than 1.3 m and planted trees. Timber quality of advance growth, > 1.3 m at release, was poor due to high incidence of stem damage, most likely inflicted during the logging operation. Potential timber quality of planted Scots pines was better among dominated than dominating trees. Volume production was more than twice as high in the plantation as in the stand originating from advance growth. Slash burning after clear felling had a positive effect on production in the plantation.     

Comparing volume growth in pure and mixed stands of Pinus sylvestris and Quercus pyrenaica

? In Mediterranean forestry, it is important to improve knowledge about mixed stands dynamics, including their productivity. Previous studies have focused on the interactions between different species (competition, reduction of competition and facilitation) depending on site, species composition and structure.

? At the centre of this research are the possible differences between pure and mixed stands of Pinus sylvestris and Quercus pyrenaica in terms of density-growth relationships and volume growth per species.

? Using data from the second and third Spanish National Forest Inventory (606 plots), volume increment models for these species were fitted. Both species displayed a similar density-growth pattern for pure and mixed stands, with a maximum volume growth at maximum density. Volume increment per occupied area was also found to be greater in mixed stands as opposed to pure stands, suggesting a species interaction with reduced levels of competition in the former. However, the total volume growth was generally lower in mixed stands since the growth rate of oak is much lower.

? The results highlight the expedience of favouring P. sylvestris-Q. pyrenaica mixed stands with higher proportions of pine trees in order to gain the benefits of a more complex forest whilst retaining an acceptable level of wood production.

     

Root growth capacity and field performance of Pinus sylvestris and Picea abies seedlings

Correlations between root growth capacity (RGC), at the time of planting, and field performance were studied for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings. Before planting a gradient in seedling viability was generated through exposure to low root temperatures and different winter storage regimes. The hypothesis that high RGC values would improve field performance was to some extent verified for pine seedlings while no correlations could be registered for spruce. Reasons for these results are discussed.     

Lightwood induction in Pinus sylvestris by means of mechanical wounding

In a field experiment the influence of different girdling patterns like wide girdling, longitudinal debarking, debarking with one or several bridges, narrow girdling and bark crushing on resin soaked wood formation (lightwood) in Pinus sylvestris L. trees was investigated. Four years after treatment the concentrations of total extractives and resin acids were measured. It is shown that treatment methods differently affected concentrations of total extractives and resin acids. Longitudinal debarking with a wide bridge and debarking with several narrow bridges were the most successful methods for lightwood induction.     

Effects of temperature on shoot growth in northern provenances of Pinus sylvestris L

Effects of temperature on shoot growth in northern provenances of Pinus sylvestris L. were studied under natural long-day conditions (Lat. 69 degrees 39' N) at controlled temperatures. The optimum constant temperature for formation of stem unit primordia in the terminal resting bud was 18 to 21 degrees C. Stem unit number decreased linearly with temperature between 15 and 9 degrees C. Temperature during bud formation had a significant effect on final stem unit length achieved in the following year. Final shoot length was significantly affected by temperature during shoot elongation. The optimum constant temperature for elongation growth was 18 to 21 degrees C. The rate of shoot elongation was positively correlated with the number of stem units.     

毛乌素沙地气候因子对樟子松、油松生长的影响

调查了毛乌素沙地沙漠研究中心樟子松、油松人工林的生长状况,选取可能影响其生长的气候因子并运用双重筛选逐步回归的方法,对樟子松和油松高生长与气候因子间的关系进行了逐步判别分析.结果表明：影响樟子松树高生长量的主导气候因子依次是前一年的降雨量、≥10℃积温、年蒸发量;影响油松生长的气候因子主要是前一年降雨量与当年降雨量;该区樟子松的生长表现明显好于油松,并且在干旱年份表现出更强的抗旱特性,所以该地区的气候条件更适合樟子松的生长.     

Effects of growth regulators on germination of picea abies and Pinus sylvestris seeds

Nine seed lots each of Norway spruce (Picea abies L.), and Scots pine (Pinus sylvestris L.) were treated with combinations of the growth regulators: Indole‐3‐acetic acid, indole‐3‐butyric acid, etephone, kinetin, fusicoccin, and the gibberellins A₁ A₃ A_4/7, and A₉. GA₉ GA_4/7 and fusicoccin significantly promoted the germination of five Norway spruce, and three Scots pine, seed batches. Independent of species, the germinability of seeds treated with auxins, etephone, kinetin, GA₁ and GA₃ were unaffected or reduced. The rate of germination was stimulated for both species when treated with GA₉ or GA_4/7. The germination percentage for Scots pine seeds was enhanced by GA₉ but not by GA_4/7. Neither of the two GAs enhanced the germination percentage of Norway spruce seeds.     

Intraspecific variation in Heterobasidion annosum for growth in sapwood of Picea abies and Pinus sylvestris

Two greenhouse experiments were conducted to study intraspecific variation in growth of the root rot fungus Heterobasidion annosum in living host sapwood. In experiment 1, Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) seedlings were inoculated with H. annosum isolates, 14 each of the S-and P-intersterility groups, collected from various parts of Sweden. In pine, the P-group isolates were more virulent than the S-group isolates both in terms of infection frequency, induced mortality rate (p < 0.05), and fungal growth in sapwood (p < 0.05). In spruce, the P-group isolates were also more virulent on average, but the difference was not statistically significant. Both S and P isolates had a higher infection frequency and a significantly longer sapwood growth on spruce than on pine. The P-group caused higher mortality on pine than on spruce. The length of the lesion in the inner bark was strongly correlated with fungal growth in spruce, but not in pine where the lesions were short or absent. In experiment 2, ten Norway spruce clones were inoculated with 18 S-isolates, originating from nine live-decayed trees and from nine spore-infected stumps in a single Norway spruce stand. The objective was to test whether any selection for growth rate in sapwood was detectable among individuals of H. annosum originating either from stumps or trees. The results gave no support for such selection since no difference in sapwood growth between the two groups of isolates was found.