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1.
Tadashi Ogawa Chisato Matsumoto Chisato Takenaka Takafumi Tezuka 《Journal of Forest Research》2000,5(2):81-85
The effect of CA(NO3)2 on the active oxygen scavenging system in hinoki cypress (Chamaecyparis obtusa) seedlings cultured in a nutrient solution containing aluminum was examined. The hinoki cypress seedlings were transferred
to nutrient solutions containing 5 mM AlCl3 together with various concentrations of Ca(NO3)2 in pots containing glass beads and Teflon tips. The growth in height and dry matter allocation to each organ was little influenced
over a period of 12 weeks by either Al or the concentration of Ca(NO3)2. The activity of superoxide dismutase (SOD) in the needles was stimulated by Al, and the effect of Al was lowered significantly
by simultaneous application of 25 mM Ca(NO3)2. At week 1, the activity of catalase (CAT) in the needles was increased by Al, but the effect was no longer observed at week
12. The Al concentration in the roots was increased by treatment with Al, whereas the Al concentration in needles was not.
These results indicate that rhizospheric Al stress stimulates antioxidative enzyme activities in hinoki cypress needles and
the activation of the enzymes is suppressed by addition of Ca. The transmission of Al stress to the needles, which induced
a change in the enzyme activity, is not caused by the transfer of the Al ion itself from roots to needles.
This work was supported in part by funding from the Japan Science and Technology Corporation, the CREST program 1996–2001,
and the Center for Forest Decline Studies. 相似文献
2.
Lin Shanzhi Zhang Zhiyi Lin Yuanzhen Liu Wenfeng Guo Huan Zhang Wei Zhang Chong 《中国林学(英文版)》2004,6(3):1-8
To explore the physiological and biochemical mechanism of the occurrence of vitrified shoots of Populus suaveolens in tissue culture, the changes in water, chlorphyll, lignin, H2O2, phenylalanine ammonialyase (PAL), malonaldehyde (MDA), protective enzymatic systems, and some key enzymes involved in the
ascorbate- glutathione cycle were comparatively studied in both normal and vitrified shoots of P. suaveolens. The results show that the lower activities of peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate
reductase (DHAR), glutathione reductase (GR) and PAL, and the less contents of chlorphyll, lignin, ascorbate (ASA) and reduced
glutathione (GSH) as well as the lower ratios of ASA / DHA and GSH / GSSG are observed in vitrified shoots than in normal
ones during the whole culture period. While in comparison with normal shoots, the higher activity of superoxide dismutase
(SOD) and the more concentrations of water, H2O2, MDA, dehydroascorbate (DHA) and oxidized glutathione (GSSG) are found in vitrified shoots. Statistical analysis indicates
that the enhanced activity of SOD and the decreased activities of CAT and POD as well as some enzymes involved in the ascorbate-glutathione
cycle might be closely correlated to the accumulation of H2O2. The less regeneration of ASA and GSH and the lower capacity of the ascorbate-glutathione cycle observed in vitrified shoots
might be due to a significant decrease in APX, MDAR, DHAR and GR activities and a decline in redox status of ASA and GSH.
The decreases in chlorphyll content might result in a decline in photosynthesis. The lower activities of POD and PAL could
result in the decrease of lignin synthesis and cell wall ligination, which might be the key factor leading to the increase
in water content. It is concluded that the deficiency of detoxification capacity caused by the lower capacity of the ascorbate-glutathione
pathway and the decreased activity of protective enzymatic system might lead to the large accumulation of H2O2 and the enhancement of membrane lipid peroxidation, which might be the main cause leading to the occurrence of vitrifying
shoots of P. suaveolens in tissue culture.
[Supported by National Natural Science Foundation of China (Grant No. 30271093) and the Foundation of State-designated Base
for Biology Researching and Teaching in Beijing Forestry University] 相似文献
3.
Tomoaki Takahashi Kazukiyo Yamamoto Yosuke Miyachi Yoshimichi Senda Masashi Tsuzuku 《Journal of Forest Research》2006,11(2):117-123
Penetration rates of laser pulses transmitted from a small-footprint airborne light detection and ranging (LiDAR) system in
closed-canopy, middle-aged (40–50 years old) hinoki cypress (Chamaecyparis obtusa Sieb. et Zucc.) and sugi (Cryptomeria japonica D. Don) plantations that had similar levels of canopy openness were studied. The number of transmitted pulses was 107 427
points/ha for the hinoki cypress stand and 122 883 points/ha for the sugi stand. The penetration rates of the first (Pf) and second pulses (Ps) that reached the ground were 0.1% and 1.0% in the hinoki cypress stand, and 2.6% and 5.5% in the sugi stand, respectively.
Penetration rates for the total number of pulses (Pf+s) that reached the ground within each stand were 1.1% and 8.1%, respectively, and values for Pf+s, Pf, and Ps for sugi and hinoki cypress stands were significantly different (P < 0.001). The results of this study indicated that the generation of accurate digital terrain models in dense hinoki cypress
stands with complex topographies using only the data from laser pulses with poor laser penetration rates is likely to be difficult. 相似文献
4.
The role of antioxidant system in freezing acclimation-induced freezing resistance of Populus suaveolens cuttings 总被引：1，自引：0，他引：1
We investigated the changes in the contents of H2O2, malonaldehyde (MDA) and endogenous antioxidants, the activities of protective enzymes and some critical enzymes involved in the ascorbate-glutathione (ASA-GSH) cycle as well as freezing resistance (expressed as LT50) and correlations mentioned above, in detail using Populus suaveolens cuttings. The purpose was to explore the physiological mechanism of the enhancement of freezing resistance induced by freezing acclimation at –20°C, and to elucidate the physiological mechanisms by which trees adapt to freezing. The results showed that freezing acclimation enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), monodehydroascorbate reductase (MDAR), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR). And it increased the contents of reduced ascorbate (ASA), reduced glutathione (GSH), dehydroascorbate (DHA) and oxidized glutathione (GSSG). However, H2O2 and MDA contents and LT50 of cuttings were decreased. LT50 in cuttings was found to be closely correlated to the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, H2O2, MDA, ASA, GSH, DHA and GSSG during freezing acclimation. This suggested that the enhancement of freezing resistance of cuttings induced by freezing acclimation may relate to the distinct increase for the levels of SOD, POD, CAT, APX, DHAR, MDAR, GR, ASA, GSH, DHA, and GSSG. In addition, the observed levels of APX, DHAR, MDAR, GR, ASA, DHA, GSH and GSSG were higher than those of SOD, POD and CAT during freezing acclimation. It indicated that a higher capacity of the ASA-GSH cycle is required for H2O2 detoxification, and growth and development of cuttings. Based on the obtained results, it can be concluded that the ASA-GSH cycle plays an important role in enhancement of freezing resistance of P. suaveolens cuttings during freezing acclimation. 相似文献
5.
Comparative Study on Antioxidative System in Normal and Vitrified Shoots of Populus suaveolens in Tissue Culture 总被引：1，自引：0，他引：1
To explore the physiological and biochemical mechanism of the occurrence of vitrified shoots of Populus suaveolens in tissue culture, the changes in water, chlorphyll, lignin, H202, phenylalanine ammonialyase (PAL), malonaldehyde (MDA), protective enzymatic systems, and some key enzymes involved in the ascorbate- glutathione cycle were comparatively studied in both normal and vitrified shoots of P suaveolens. The results show that the lower activities of peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR) and PAL, and the less contents of chlorphyll, lignin, ascorbate (ASA) and reduced glutathione (GSH) as well as the lower ratios of ASA / DHA and GSH / GSSG are observed in vitrified shoots than in normal ones during the whole culture period, While in comparison with normal shoots, the higher activity of superoxide dismutase (SOD) and the more concentrations of water, H2O2, MDA, dehydroascorbate (DHA) and oxidized glutathione (GSSG) are found in vitrified shoots. Statistical analysis indicates that the enhanced activity of SOD and the decreased activities of CAT and POD as well as some enzymes involved in the ascorbate-glutathione cycle might be closely correlated to the accumulation of H202. The less regeneration of ASA and GSH and the lower capacity of the ascorbate-glutathione cycle observed in vitrified shoots might be due to a significant decrease in APX, MDAR, DHAR and GR activities and a decline in redox status of ASA and GSH. The decreases in chlorphyll content might result in a decline in photosynthesis. The lower activities of POD and PAL could result in the decrease of lignin synthesis and cell wall ligination, which might be the key factor leading to the increase in water content. It is concluded that the deficiency of detoxification capacity caused by the lower capacity of the ascorbate-glutathione pathway and the decreased activity of protective enzymatic system might lead to the large accumulation of H2O2 and the enhancement of membrane lipid peroxidation, which might be the main cause leading to the occurrence of vitrifying shoots of P.suaveolens in tissue culture. 相似文献
6.
Koji Yoshida Shoko Inaba Chisato Takenaka Takafumi Tezuka 《Journal of Forest Research》2005,10(2):157-161
To clarify the nutrient status in momi fir (Abies firma Sieb. et Zucc.) seedlings under complex stress conditions of acid fog with soil acidification or nitrogen loading, we exposed seedling shoots to simulated acid fog (pH 3) and simultaneously loaded the soil with acid or excess nitrogen for 17 months. Proton and nitrogen loading reduced K concentration in soil, but these treatments had little effect on the nutrient status of fine roots in momi fir seedlings. Acid fog exposure resulted in reduced concentrations of Mg, Al, and Fe in current-year needles and Mg, Al, Cu, Fe, and Zn in 1-year-old needles. The complex effects of acid fog exposure with proton or nitrogen loading on nutrient status were relatively slight. However, elements such as Al and Cu notably reflect the effects of proton loading. These results show that the nutrient status of trace elements, rather than major elements, in needles of momi fir seedlings is sensitive to exposure to acid fog or proton loading. 相似文献
7.
We exposed momi fir (Abies firma Sieb. et Zucc.) seedlings to simulated acid fog of pH 3.0 for about 3 years (from July 1999). During the last year of acid fog exposure, half of the seedlings were subjected to rhizosphere Al stress (complex stress) and the nutrient status of seedlings was determined. Chronic acid fog exposure decreased Fe and Zn concentrations in current-year and 1-year needles, and Al in 1-year needles, but had little effect on major element concentrations. Aluminum treatment had a broad impact on nutrient status in fine roots and needles. In fine roots, increases in Al and Cu concentrations and decreases in B, Mn, and Zn concentrations were observed. In 1-year needles, Al treatment increased Al, B, and Mn concentrations and decreased Cu concentration. The complex effect of acid fog with aluminum on nutrient status was relatively slight. These results show that changes in nutrient status under chronic acid fog exposure and/or Al stress are induced before the decline of photosynthesis in momi fir seedlings, mainly due to Al stress. 相似文献
8.
[目的]研究低磷胁迫对杉木幼苗各种抗氧化酶等生理指标的变化影响,探讨抗氧化酶活性与杉木耐低磷能力的关系,揭示低磷胁迫下杉木养分吸收的适应机制,阐明杉木体内生物大分子对低磷胁迫的响应。[方法]通过设置不同磷浓度(0、0.25、0.50、1.00 mmol·L~(-1))Hoagland营养液,模拟低磷胁迫试验,测定低磷胁迫对杉木幼苗的生理指标的影响,研究低磷胁迫对杉木幼苗养分吸收的影响机制以及测定杉木幼苗不同部位的光谱特性。[结果]随着缺磷程度的增加,杉木幼苗中SOD活性、CAT活性以及叶绿素a、叶绿素b和叶绿素总量均先升后降,根系中POD活性呈现出升高的趋势、MDA含量先降再升后降,叶片中POD活性和MDA含量先降后升。低磷胁迫对杉木幼苗根系和叶片吸收利用营养元素有显著影响。杉木苗根系所含的Mn随着缺磷程度的增加呈上升趋势,而Al和Cu先降后升,Fe和K则有所下降,Ca先升后降。此外,杉木叶片中Fe和Mn的积累量呈降低的趋势,Cu和K先升后降。低磷胁迫对杉木幼苗根系和叶片组织在3 367、2 924、1 736、1 630、1 380、1 150 1 000 cm~(-1)处特征峰吸光值影响不同。[结论]低磷胁迫下,杉木幼苗的根系和叶片会通过改变保护酶(SOD、CAT和POD)活性抑制MDA形成,降低膜脂过氧化对细胞膜系统的破坏,通过增加对其他养分元素的吸收来规避损伤以及通过改变不同部位糖类、氨基酸和蛋白质等物质含量来适应低磷环境。 相似文献
9.
We investigated the short-term and long-term mitigation of Al toxicity by Ca and Mg in pot trials of Japanese cedar (Cryptomeria japonica D. Don). We found that in the initial stages of treatment, Al toxicity at high Al concentration (5mM) was mitigated by Ca and Mg through the stimulation of antioxidant enzyme activities in needles. However, growth reduction occurred after 11 months exposure to Al despite the coexistence of Ca and Mg. Growth reduction was related to Al3+ activity in solution rather than the concentration of Ca and Mg. Therefore, when considering the influence of soil acidification on Al toxicity in forest ecosystems, it is important to consider not only the potential for mitigation of Al toxicity by base cations, but also the potential for factors in the soil solution to change the chemical form of Al. 相似文献
10.
Katsuaki Ishii 《Journal of Forest Research》2002,7(2):99-104
Hinoki cypress (Chamaecyparis obtusa) is one of the most important timber resource forest trees in Japan. Because seed production from a seed orchard of hinoki
cypress is not constant every year, micropropagation from a limited amount of material is useful. Up to now, the conventional
tissue culture method using solid medium has been used. Here a new method using liquid culture in tubes rotated vertically
is described. Shoot primordium of hinoki cypress was inoculated in Campbell and Durzan’s (CD) liquid medium containing different
cytokinins (6-benzylaminopurine (BAP), Zeatin, thidiazurone (TDZ)), and the container tubes were rotated vertically around
the axis at 2 times / min. Culture room temperature was 25°C and light condition was 16 h photoperiod per day of fluorescent
lamps. Zeatin at 1μM concentration was the best for maintaining the shoot primordium production and TDZ induced callus on the surface of the
shoot primordia. After shoot primordium multiplication in the liquid culture, they were transplanted to agar medium for shoot
elongation. A high concentration of agar (up to 16 g/L) or AVF (anti vitrification factor from Dr. Nairn, 1995) was effective
to prevent vitrification of the shoots. Transformation of shoot primordium was done using particle bombardment with vectors
containingβ-glucuronidase (GUS) gene or herbicide resistance gene (bar). Positive result for transient transformation was observed with the histo-chemical study for transformation with GUS. Integration
of a useful herbicidebar gene into the shoot primordium culture system was also tried and stably transformed plants were obtained. This is the first
report of stable transformation of Japanese conifer using practically useful gene.
The generous supply of AVF-B from Dr. B.J. Nairn, Tasman Forestry, NZ is also appreciated. 相似文献
11.
SONG Fu-nan YANG Chuan-ping LIU Xue-mei LI Gong-bin 《林业研究》2006,17(1):13-16
The injury tolerance of cell plasma membrane and the correlative enzymes activities of plasma-membrane protection system in the Ulmuspumila leaves treated by nine concentrations （0.3%, 0.6%, 0,9%, 1,2%, 1.5%, 1.8%, 2,1%, 2.4%, 3.0%） of Na2CO3 and NaHCO3 mixtures were studied in a greenhouse of Northeast Forestry University, Harbin, China. The rate of electrolyte leakage （REL） and SOD （Superoxide dismutase） activity in leaves of different samples were determined. Results showed that the REL in leaves of U. pumila presented a slowly increasing trend at the salt concentrations less than 1.5%, which indicated that cell plasma membrane of U. pumila leaves had rather strong resistance to the injury of salt ion, and had a significant increase at the salt concentrations more than 1.5%. The SOD activities in leaves of U, pumila presented an increased trend at salt concentrations less than 1.5%, the growth of seedlings did not decline, and tress and leaves had no symptom of injury, while the salt concentrations exceeded 1.5%, SOD activities sharply decreased and REL increased promptly. 相似文献
12.
The cutting seedlings ofLiriodendron chinense xtulipifera were treated with the different concentrations of auxin (treatment1: IBA of 50 g·kg−1+NAA of 300 g·kg−1; treatment2; IBA of 100 g·kg−1+NAA of 300 g·kg−1). The biomass nutrient element contents for different organs (root, stem, leaf) of cutting seedling ofLiriodendron chinense xtulipifera were measured by the dry method, Kjeldahl method and Atomic Absorption Spectroscopy method. The result showed that the biomass
of root, stem, and leaf of the cutting seedling treated with auxin was all remarkably increased. The contents of element C
in root, stem and leaf had no significant difference between the control and auxin treatments, while the contents of N, P,
K and Ca in stem were much lower than that in leaf and root. Variance analysis showed that for the same organ with different
concentration treatment of auxin, the four nutrient elements (N, P, K, and Ca) had no significant difference in contents,
while there existed significant or very significant difference in contents of the four nutrient elements in different organs
with the same concentration auxin treatment. The N, P, K and Ca contents were very low in cutting seedlings; as a result,
additional fertilizer should be applied to the seedlings when they were planted in the field.
Foundation item: This paper was supported by Jiangsu Province Science Foundation (BE96350).
Biography: ZHANG Xiao-ping, (1972-), female, Ph. Doctor in Nanjing Forestry University. Nanjing 210037, P. R. China.
Responsible editor: Zhu Hong 相似文献
13.
[目的]在不同供Ca2+水平下对马尾松幼苗生长及生理特性进行研究,以确定适宜马尾松生长的钙浓度,为马尾松人工林培育及合理施用钙肥提供参考。[方法]以半年生马尾松幼苗为试材,采用温室内砂培,研究不同供Ca2+水平(0.0、0.4、1.0、2.0、3.0、4.0 mmol·L~(-1)(CK))对马尾松生长及生理指标的影响。[结果]不同供Ca2+水平处理5个月后,在Ca2+水平为1.0、2.0 mmol·L~(-1)时,马尾松幼苗的株高增量和地径增量较高,其中,2.0 mmol·L~(-1)Ca2+水平的株高增量和地径增量最高。马尾松幼苗对Ca2+水平适应能力强弱顺序为2.01.00.43.00.04.0 mmol·L~(-1)(CK)。在不同生长期内,随着供Ca2+水平的增加,马尾松针叶中ROS(O2-产生速率、H2O2浓度)、MDA含量、抗氧化酶(SOD、POD、CAT和APX)活性、抗氧化物质(GSH、As A)含量、脯氨酸含量均先降低后增加,最小值均在1.0 mmol·L~(-1)或2.0 mmol·L~(-1)处理中;类胡萝卜素含量先增加后降低,其最高值均在2.0 mmol·L~(-1)处理中。马尾松幼苗的株高增量和地径增量与类胡萝卜素含量关系不明显,而与其他生理指标均呈显著负相关。[结论]马尾松幼苗适宜在1.0 2.0 mmol·L~(-1)Ca2+水平的环境中生长。在马尾松林地中,应对土壤有效钙含量进行测定,并结合植株的生长和生理特征进行综合评价后,科学合理施肥以提高生产力。 相似文献
14.
Zaizhi Zhou Kunnan Liang Daping Xu Yuchen Zhang Guihua Huang Huaming Ma 《New Forests》2012,43(2):231-243
Many teak plantations are established on acidic soils with low nutrient availability. There is also poor documentation of
nutrient budgets for teak, therefore, a pot experiment with optimal hybrid regression design (Roquemore R311A) was implemented
with calcium, boron and nitrogen treatments with teak seedlings (Tectona grandis L.f.) planted in acidic lateritic red soil substrate. Seedling growth, biomass production and root development, and soil
pH, and exchangeable Ca and Al concentration were measured. Plant height, root collar diameter, biomass of leaves, stems and
roots, root volume, taproot length, number of lateral roots of teak seedlings were significantly and positively correlated
with soil exchangeable Ca, pH and Ca/Al molar ratio, and negatively correlated with exchangeable Al. All growth traits were
significantly affected by calcium, nitrogen and their interaction, but B fertilizer and other interactions had insignificant
effects. To effectively cultivate teak seedlings in acidic soil substrates, 1.68 g kg−1 quicklime (CaO) and 0.65 g kg−1 urea was suggested to be added to neutralize soil acidity, and enhance soil exchangeable Ca content and Ca/Al molar ratio.
Urea should not be added without quicklime. 相似文献
15.
Asami Nakanishi Yoshiyuki Inagaki Naoya Osawa Shozo Shibata Kei’ichi Hirata 《Journal of Forest Research》2009,14(6):388-393
Leaf nitrogen nutrition of hinoki cypress (Chamaecyparis obtusa Endlicher) was investigated at three positions along a slope over a period of 3 years. At each slope position, nitrogen properties
were compared in patch-cut plots (0.06–0.09 ha) and uncut control plots (0.04 ha). Nitrogen cycling at the lower slope was
characterized by a higher rate of soil nitrogen mineralization, and higher nitrogen concentration in fresh leaves and leaf-litter.
The soil nitrogen mineralization rate and fresh-leaf nitrogen concentration in the patch-cut plots were higher than those
in the control plots. However, leaf-litter nitrogen concentration did not differ between the patch-cut and control plots.
The results suggest that slope position strongly affects leaf nitrogen nutrition of hinoki cypress and soil nitrogen availability.
By contrast, patch cutting does not affect leaf-litter nitrogen concentration. These findings indicated that hinoki cypress
would not enhance forest nitrogen cycling through changes in leaf-litter nitrogen concentration after patch cutting. 相似文献
16.
This study was conducted to investigate the potential for modifying drought tolerance of Japanese cypress (Chamaecyparis obtusa Endl.) and Japanese red pine (Pinus densiflora Sieb. et Zucc.). Three-year-old seedlings were controlled for five-months at three different soil water potentials ({ie73-1}).
Japanese cypress exposed to high {ie73-2} was able to maintain higher photosynthesis (Phn), transpiration (Tr) and stomatal conductance to H2O (gH2O) in comparison to low {ie73-3} pretreatments, however, there was no significant difference in Phn for Japanese red pine. Soil water potential at the threshold from the maximum to limited Phn was higher in high {ie73-4} pretreatments than in low {ie73-5} pretreatments. Net photosynthesis, Tr and gH2O decreased more rapidly in high {ie73-6} pretreatments than in low {ie73-7} pretreatments. Transpiration decreased more significantly
than Phn, thus, resulted in increased water use efficiency. All these factors are likely to result in significant improvements in
the drought tolerance. Japanese red pine seems more drought-tolerant than Japanese cypress. Japanese cypress is suitable to
soil of −0.05 MPa water potential, and Japanese red pine is suitable to −0.16 MPa and even dryer soils. 相似文献
17.
在CO_2浓度升高和对照处理的两个开顶式气室(OTC-Ⅰ型)内,研究分析了高浓度CO_2对落叶松针叶抗氧化系统酶活力的影响。结果表明:短期内(2个月左右)CO_2浓度升高条件下,超氧化物歧化酶(SOD)、抗坏血酸(ASA)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)含量上升,且SOD与O_2·~-产生速率之间呈极显著负相关;但长期高浓度CO_2处理下,ASA含量与SOD、APX、GR活性略有下降,可见,较长期高浓度CO_2处理可能使此效果发生逆转。在CO_2浓度升高条件下,植物可能通过抗氧化能力的增强来减轻胁迫造成的细胞损伤,从而增强植物的抗性。 相似文献
18.
Fall nutrient loading of deciduous forest nursery seedlings is of special interest because of foliage abscission and varied translocation patterns. For non-deciduous seedlings in the nursery, fall fertilization typically can reverse nutrient dilution and possibly increase nutrient reserves; however, this technique has received little attention with deciduous conifer trees that translocate nutrients before abscising foliage. We evaluated how fall nitrogen (N) fertilization affected N storage and translocation in the deciduous conifer Olga Bay larch (Larix olgensis Henry) seedlings during the hardening period. Seedlings were supplied with 25 mg N seedling?1 for 15 weeks before hardening and fall fertilization treatments began with a three week application period of K15NO3 at 0, 5, 10 and 15 mg N seedling?1. During the hardening period, fall N fertilization had little effect on seedling morphology. The N concentration and content of needles decreased dramatically as needles abscised, while that of stems and roots increased. Six weeks after fall N fertilization ceased, all seedlings translocated similar net N from their needles. For the control seedlings, this accounted for 84 % of the N stored in stems and roots. For fall fertilized seedlings, however, the proportion of N stored in stems and roots translocated from needles accounted for only 41–61 % of the total because of absorption of fall fertilizer that was translocated directly to stems and roots. Six weeks after fall fertilization, the distribution pattern of N concentration and content in seedlings was found in this order: stems > fine roots > coarse roots > needles. Our results suggest that providing deciduous conifer seedlings N during hardening, in this case Olga Bay larch, is a way to promote nutrient loading during nursery production. 相似文献
19.
Cold hardened, dehardened, and newly flushed foliage of one year old white spruce (Picea glauca [Moench.] Voss) seedlings were exposed to various sub-zero temperatures (--2 to --22.5°C) either in the dark or light. The freezing treatment had no significant effect on the variable fluorescence to maximal fluorescence ratio (Fv/Fm) of hardened seedlings, either in the light or dark. Also, no visible damage or increase in electrolyte leakage were evident in either the light or the dark treated seedlings. Both dehardened and newly flushed foliage were significantly affected by the freezing treatment, and light enhanced the effect. A decline in Fv/Fmincreased electrolyte leakage and visible damage were observed at warmer temperatures in newly flushed needles than in dehardened needles. Seedlings exposed to sub-zero treatments in the light also had lower Fv/Fm, increased electrolyte leakage and showed more visible damage than seedlings exposed to the same sub-zero treatments in the dark. The temperature where 50% of the needles were damaged (LT50) as estimated from visible damage data was --10.8°C in the light and --12.1°C in the dark for dehardened, one year old needles. The LT50in newly flushed needles was --4.8°C in the light and --6.2°C in the dark. Recovery of Fv/Fmvalues 3 days after freezing exposure was only evident in treatments where little visible damage was present. Both Fv/Fmand electrolyte leakage were strongly correlated with visible damage. 相似文献
20.
We estimated the water status of six 31-year-old hinoki cypress (Chamaecyparis obtusa) trees that were struck by a large typhoon. Measurements were made of the trunk water-conduction area of xylem, leaf water potentials, and diurnal changes in trunk diameters. The secondary woodboring insects, Callidiellum rufipenne and Ovalisia vivata, on the trees were captured by the sticky-trap banding method. In trees on which these wood borers were captured, water conduction areas were reduced, leaf water potentials were lower, and trunk diameter changes (R) fluctuated during the day, suggesting that the trees had been damaged by the typhoon and were under water stress. The secondary woodboring insects attacked the water-stressed trees. 相似文献