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1987年从四川黔江县引进白花泡桐种子,进行两段育苗试验.即地膜覆盖母床培育小苗,二段移植扩床培育大苗.结果表明:1.地膜覆盖后由于水热条件改善,促使早出苗,与露地育苗比,播种期提前6天,种子发芽出土始期提前30天,出苗终期提前39天,提高了出苗整齐度. 相似文献
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为加快银杏造林绿化速度,作者于1989年进行了银杏快速育苗技术研究。本研究选用当地银杏优良品种大圆铃种子进行播种造林,采取大粒种子与小粒种子、覆膜与不覆膜、摘心与不摘心3种对比试验方法。试验结果表明,大粒种子培育出的幼苗优于小粒种子;温室催芽继而覆膜播种比不覆膜的种子育苗,速生期提前10天;采取摘心处理,促进了叶、茎、根的生长。 相似文献
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用植物调节剂ＤＡ和ＤＢ处理水曲柳种子的最佳浓度为５０ｍｇ／Ｌ。种子处理后可提前出苗２０天，成苗率提高８％－１０％，苗木高生长、地茎生长、主根长度和根幅均有显著提高。 相似文献
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核桃种子若不进行处理,不仅出苗缓慢、出苗率差,甚至当年不能出圃。为了探索种子处理的最佳方法,我们开展了核桃种子不同处理方法的试验。通过试验沙藏催芽法效果最好。此法与温水渍泡法相比,出苗期提前了20天,出苗率提高了15.2％,苗高和地径生长量分别提高了35％和25％,值得大力推广。 相似文献
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大兴安岭林区气候嚴寒,桦木种子在八月下旬至九月上旬成熟。其它地区气候比較温暖,可以提前15——20天成熟。 樺木果实成熟时期的特征是:果穗呈黃褐色,用手指一捻立即散开。采种应在种子完全成熟的前几天進行,但不要从幼齡的母樹上采集,因为幼龄母樹所結的种子發芽率很低(只有8——15％);此外,要避免采集帶有僵化病的种子。这样才能保証种子的質量,使采集的种子有較高发芽率(一般可以达到30——40 相似文献
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经调查,陕北黄土区小哭属(Berberis)植物资源有6种,蕴藏量3000担左右。可分为抗旱、中生和湿生3种生态类型。播种育苗试验,种子沙藏处理比热水浸种和干播,平均出苗率分别提高9%和15%,平均提前5天、10天。 相似文献
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不同采收期对黄山松种子品质的影响 总被引：3，自引：0，他引：3
对在霜降日及提早半个月和1个月采收的黄山松种子的播种品质作了比较分析,结果表明霜降日采收的种子其千粒重、发芽率、发芽势和种子活力指数都要比提前采种的高11.4％～175．3％,采种时间越提前,品质越差。因此,分布在高海拔地区的黄山松采种时间应严格掌握在霜降前后,不能提前半月以上,否则将严重影响种子品质。 相似文献
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连翘扦插繁殖技术的研究 总被引：4，自引：0，他引：4
在延边地区３月下旬采条,剪条,催根,４月中下旬扦插,加强插床管理,控制温湿度,其生根成活率可达９８％以上,到６月中下旬起出移植到大田,其当年苗高可达５０－６０ｃｍ,可为第２年绿化提供健壮的苗木。 相似文献
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干旱胁迫对不同种源沙柳苗木水势和水分利用效率的影响 总被引：2，自引：0，他引：2
通过人工模拟方式对5个种源沙柳苗木进行干旱胁迫处理,研究干旱处理不同阶段苗木小枝水势日变化、叶片相对含水量、水分饱和亏缺、保水力及水分利用效率。结果表明:干旱胁迫下5个种源的沙柳苗木小枝水势和叶片相对含水量均下降,而水分利用效率在轻度干旱时呈上升趋势,随干旱胁迫的加剧而下降。干旱处理15天后,民勤种源的沙柳日平均小枝水势下降幅度最大为0.77 MPa,然后依次为达拉特旗0.57 MPa、盐池0.36 MPa、榆林0.25 MPa和乌审旗0.12 MPa,其中民勤种源的苗木在充分供水和干旱胁迫下小枝水势差异达到显著。干旱处理18天后叶片相对含水量分别下降:民勤1.68%、盐池7.03%、达拉特旗7.25%,榆林9.35%和乌审旗11.07%,水分饱和亏缺民勤<盐池<达拉特旗<榆林<乌审旗。结果表明,民勤种源的沙柳抗旱的能力较强,而盐池和达拉特旗沙柳苗木在受到水分胁迫时水分利用效率下降幅度较小,即水分胁迫对苗木干物质的积累影响较小,因此具有更高的经济价值。 相似文献
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Changes in photosystem II (PSII) thermotolerance during drought and recovery were studied under controlled conditions in three Mediterranean cedar species (Cedrus brevifolia Henry, C. libani Loudon and C. atlantica Manetti). The temperature at which the quantum yield of PSII photochemistry was reduced by 15% of its value at 25 degrees C was 3 to 4 degrees C higher in drought-treated plants than in well-watered plants. The drought-induced increase in PSII thermotolerance was already evident 8 days after water had been withheld from the seedlings, when net CO(2) assimilation was still at 80% of its initial value, and was visible for up to 12 days after re-watering. When seedlings of the three species were exposed to temperatures above 45 degrees C for 5 h, both maximal quantum yield of PSII photochemistry and net CO(2) assimilation rate were significantly reduced in unconditioned seedlings, whereas drought-preconditioned seedlings were almost unaffected by the heat treatment. Drought-preconditioned seedlings still exhibited a higher tolerance to heat stress than unconditioned seedlings 60 days after re-watering, although the transient, drought-induced osmotic adjustment had fully disappeared. Among species, C. atlantica was the most heat sensitive, whereas the heat treatment had no significant effect on the parameters measured in C. brevifolia. 相似文献
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水淹胁迫对尖叶杜英和水蒲桃幼苗生理特征的影响 总被引：2，自引：0，他引：2
以尖叶杜英和水蒲桃幼苗为试验材料,人工模拟水淹胁迫环境,共设置水位在土壤表面和土表上5 cm处2种水淹强度,分别水淹7、14、21、28、35天以及水淹35天后恢复正常生长7天,测定幼苗叶片的叶绿素、可溶性糖、可溶性蛋白、超氧化物歧化酶(SOD)、丙二醛(MDA)含量。结果表明:随着水淹深度的增加,尖叶杜英幼苗的叶绿素含量多显著低于对照,水蒲桃幼苗的叶绿素含量一般大于对照;2种幼苗的可溶性糖含量一般都高于对照,水蒲桃叶片可溶性糖含量的增幅大于尖叶杜英。2种幼苗在水淹深度为5 cm时的可溶性蛋白质含量均显著小于对照。除了水淹35天外,2种幼苗其他水淹处理的SOD活性均显著大于对照;尖叶杜英幼苗的MDA含量比对照显著增加,而水蒲桃幼苗的MDA含量保持稳定。由叶绿素、可溶性糖和丙二醛的变化来判断,水蒲桃的抗水淹能力强于尖叶杜英。 相似文献
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The effects of pre-storage CO(2) enrichment on growth, non-structural carbohydrates and post-storage root growth potential of Engelmann spruce (Picea engelmannii Parry) seedlings were studied. Seedlings were grown from seed for 202 days in growth chambers with ambient (340 micro l l(-1)) or CO(2) enriched (1000 micro l l(-1)) air. Some seedlings were transferred between CO(2) treatments at 60 and 120 days. Photoperiod was reduced at 100 days to induce bud set and temperature was reduced at 180 days to promote frost hardiness development for storage at -5 degrees C for 2 or 4 months. Stored seedlings were planted in a growth chamber after thawing for one week at +5 degrees C. At 80, 120, 140 and 202 days, and at each planting time after storage, seedlings were harvested for growth measurements and analysis of starch and soluble sugar concentrations. Planted seedlings were assessed for bud break every two days and new roots > 5 mm long were counted after four weeks. Carbon dioxide enrichment increased root collar diameter and almost doubled seedling biomass, with the most obvious effects occurring after bud set. Stem height was affected only slightly and shoot/root ratios were not affected at all. Carbon dioxide enrichment increased the rate of reserve carbohydrate accumulation, but did not influence the final concentration attained before storage (accounting for 32% of seedling dry weight). Needles were the major storage organ for soluble sugars, whereas roots were the major storage organ for starch. Soluble sugars were not strongly affected by two or four months of storage, but starch was reduced by more than 50% in all plant parts. None of the CO(2) treatments had an impact on bud break or root growth potential. 相似文献
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淹水胁迫对两种栎树生长的影响 总被引：2，自引：0，他引：2
对纳塔栎、南方红栎的2 a生苗在深度淹水约20 cm、浅度淹水(完全水饱和)、对照3种水平下持续76 d的生长进行研究,其中又以抗涝性极强的落羽杉作为参照.主要测定了各树种的生物量和株高,并对外部形态特征及叶片内部解剖结构的变化进行了观察.结果表明:浅淹没有造成苗木死亡,深度淹水第49天南方红栎开始出现枯死植株,第76天纳塔栎出现轻微受害症状,落羽杉没有出现受害症状.与各自对照相比,浅淹水平对落羽杉、纳塔栎的高生长及生物量的累积均具有促进作用,且对落羽杉影响较显著,而对南方红栎影响不显著;深淹水平对落羽杉、纳塔栎的'高生长及生物量的累积影响不显著,但对南方红栎具有显著的抑制作用.同时,发现淹水对落羽杉、纳塔栎的叶片解剖性状影响不显著,而深淹水平下,数据显示南方红栎的叶片内部细胞间隙明显增大.综合表明两种栎树都具有较强的耐水性,而纳塔栎更优于南方红栎,仅次于落羽杉. 相似文献
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Cyclocarya paliurus seedlings of three provenances were treated with three levels of salt (0, 51.0 and 85.0 mmol/L NaCl) in a hydroponic system of a phytotron. The ultrastructural distribution of H+-ATPase activity and ultrastructural variation were investigated in mesophyll cells of C. paliurus seedlings after 12 or 20 days of salt treatment. The results showed that under normal growing conditions, H+-ATPase activity was low and localized mainly in the nucleus. After 12 days of salt treatment and an increase in salinity, we found that the greater the H+-ATPase activity, the lighter the damage suffered by mesophyll subcells after 20 days of salt treatment and the stronger the salt-adaptation ability of seedlings. The location of H+-ATPase, largely in the nucleus, indicated that salt-damage suffered by the seedlings was light, whereas its presence, mainly in the vacuoles, showed that salt-damage was more serious. Our preliminary conclusion is that the salt-tolerance level of C. paliurus seedlings for the three kinds of provenances was in the following order, from high to low: Huangshan seedlings from Anhui Province > Kunming seedlings from Yunnan Province > Jiujiang seedlings from Jiangxi Province. 相似文献
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Schaberg PG Shane JB Hawley GJ Strimbeck GR DeHayes DH Cali PF Donnelly JR 《Tree physiology》1996,16(6):567-574
We evaluated net photosynthesis, respiration, leaf conductance, xylem pressure potential (XPP) and cold hardiness in red spruce (Picea rubens Sarg.) seedlings exposed to either a continuous thaw (CT) or a daytime thaw with freezing nights (FN) for 8 days during mid-winter. Physiological differences between CT and FN seedlings were evident for all measured parameters. However, the temporal expression of treatment differences varied among parameters. When compared to FN seedlings, CT seedlings had higher rates of respiration following 24 h of treatment, and a higher net photosynthetic rate, leaf conductance and XPP after 48 h of treatment. The CT seedlings were significantly less cold tolerant than the FN seedlings following 4 days of thaw, whereas FN seedlings did not deharden over the 8 days of treatment. Examination of temporal trends among thaw-associated changes in physiology suggested that, although greater carbon exchange occurred as stomatal conductance increased, the transition from negative to positive net photosynthesis was not the result of increases in conductance, but may have been associated with thaw-induced increases in XPP. Because thaw-associated changes in gas exchange and cold hardiness were offset in time, we conclude that, if changes in these processes are physiologically linked, the linkage is indirect. 相似文献
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In vivo chlorophyll fluorescence kinetics was observed in naturally regenerated and planted Scots pine (Pinus sylvestris L.) seedlings growing at two adjacent sites in northern Sweden. Some seedlings were shaded from direct solar radiation and some were protected from frost at night. Air temperature and solar radiation were monitored. In vivo chlorophyll fluorescence kinetics of current-year needles was measured at both room temperature and 77 K. On clear days during August, variable fluorescence of photosystem II of needles from exposed, naturally regenerated seedlings was reduced by night frosts, whereas frost caused little change in fluorescence of needles from shaded seedlings. Overnight frost-protection reduced the inhibition of photosystem II by direct sunlight. Recovery from photoinhibitory damage occurred on cloudy days. In September, the decline of variable fluorescence of photosystem II was more pronounced in unshaded than in shaded seedlings, and coincided with frosts at night. In addition, the reduction in variable fluorescence was larger for planted seedlings than for naturally regenerated seedlings. It is suggested that the inhibition of photosystem II activity was caused by an interaction between low temperatures and light. Natural night frosts are proposed to increase the susceptibility to photoinhibition in the following day(s). 相似文献
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《Scandinavian Journal of Forest Research》2012,27(1-4):271-284
The time constant of the dehardening of one‐year‐old Scots pine (Pinus sylvestris L.) seedlings was studied in three experiments started at different times of the year. The seedlings were transferred from outside to the different controlled conditions in January (Exp. 1), March (Exp. 2) and April (Exp. 3). Changes in the frost resistance of the seedlings were followed on the basis of the temperature response of the specific impedance difference in the shoot. The time constant for dehardening at a temperature of 7.5°C was found to be about 12 days in Exp. 1, about 8 days in Exp. 2, and about 5 days in Exp. 3. the terminal bud burst when the frost resistance of the shoot had risen to about ‐10°C. 相似文献