中国亚热带高大竹类植物毛竹竹笋克隆生长的密度调节

对许多多年生克隆植物来说,大量的研究表明：当光是限制因子时,随着立地密度的不断增加,克隆分株的出生率逐渐减小、死亡率逐渐增加。本文观测了乔木状高大竹类植物毛竹竹笋的出生与存活过程,结果表明：竹笋的出生率,即每样方的出笋数,明显地随着成竹立竹度的增加而增加。更确切地说,竹笋的数量,不管是出笋数还是活笋数,都明显地随着带新叶（１龄叶）的成竹立竹度的增加而增加,而与带老叶（２龄叶）的成竹立竹度相关性不显著。并且竹笋的死亡率是非密度制约的。这可能是由于对毛竹来说,其立地总是比较开敞,而且,其竹笋的生长在很大程度上是不直接需光的。     

中国亚热带高大竹类植物志竹竹笋克隆生长的密度调节

对许多多年生克隆植物来说,大量的研究表明：当是限制因子时,随着立地密度的不断增加,克隆分株的出生率逐渐减小,死亡率逐渐增加。本文观测了乔木状高大竹类植物毛竹竹笋的出生与存活过程,结果表明：竹笋的出生率,即每样方的出笋数,明显地随着成竹立竹度的增加页增加。更确切地说,生笋的数量,不管是出笋数还是活笋数,都明显地随着带新叶的成竹立竹度的增加而增加,而与老叶的成竹立竹度相关不显著。     

毛竹的无性系生长与立竹密度和叶龄结构的关系

毛竹为单轴型散生竹,属典型的无性系植物,原产我国亚热带地区。由于其个体高大、生长迅速、产量高、材质好、分布广,长期以来,一直是我国最为重要的经济竹种。本文应用无性系生长生理整合的理论,从种群统计学的角度,探讨了毛竹林立竹密度与叶龄结构对其无性系生长潜力的影响。结果表明：由于毛竹叶的生活期为两年,１龄新叶的光合能力比２龄老叶高,每样地的出笋数、活笋数与带１龄新叶的立竹数呈正相关,而与带２龄老叶的立竹数相关性不显著。另外,竹笋的死亡率是非密度制约的。本研究结果合理地解释了常见的毛竹林产量大小年交替变化的现象。     

毛竹的无性系与立竹密度和叶龄结构的关系

毛竹为单轴型散生竹,属典型的无怀系植物,原产我国亚热带地区,由于其个体高大,生长迅速,产量高、材质好、分布广、长期以来,一直是我国最为重要的经济竹种。本文应用无性生长生理整合的理论,从种群统计学的角度,探讨了毛竹林立竹密度与叶龄结构对其无性系生长潜力的影响,结果表明：由于毛竹叶的生活期为两年,１龄新叶的光合能力比２龄老高,每样地的出笋数,活笋数与带１的龄新叶的立竹数呈正相关,而与带２龄第的立竹数相     

慈竹母株大小对克隆生长的影响

 克隆生长在慈竹种群更新中占有重要地位。本文以基径和生物量两个指标同时衡量慈竹(Neosinocalamus affinis)的母株大小,并分析了母株大小对新竹笋产生、竹笋大小和根茎大小的影响。结果表明：1）慈竹的成竹基径与一级母株基径、二级母株基径以及与2龄和3龄母株平均单株生物量呈正相关,但是成竹基径随一级母株基径增加比随二级母株基径增加而增加的速率快得多;2）慈竹母株大小与各样方中出笋数、活笋数和死笋数无显著的正相关;3）发笋母株的基径显著大于未发笋母株,但发一个笋母株与发两个以上笋母株的基径无显著差异;4）母株基径、2龄和3龄母株平均单株生物量都与根茎的长度和粗度呈显著正相关,且竹笋基径与根茎粗度也呈显著的正相关。母株大小对慈竹竹笋的影响是通过影响根茎实现的。总之,慈竹的克隆生长在个体水平受母株大小制约。     

糙花少穗竹生物学特性观察

糙花少穗竹是福建优良乡土竹种,笋材两用,其竹鞭、竹笋、幼竹生长节律与单轴散生竹毛竹相似。竹鞭垂直分布多数在土层20 cm范围,4~15 m长的鞭系占78.1%,发笋期较集中在3月中下旬,单个笋重为盛期笋> 初期笋> 末期笋。从笋出土到幼竹高生长停止,可分为初期、上升期、盛期和末期。但竹鞭垂直分布比毛竹浅,出笋期比毛竹早,且出笋没有明显的大小年,具有较高的开发利用价值。在自然分布区可根据其生物学特性、竹鞭生长与发笋成竹规律采取相应技术措施,垦复改造荒芜野生竹林,2~3年即可郁闭成林。     

施肥对毛竹（Phyllostachys pubescens）竹笋生长的影响

 毛竹(Phyllostachys pubescens)为具有重要经济价值的高大乔木状竹种。本文通过完全随机化区组施肥试验,探讨了施肥量及施肥方式对毛竹竹笋生长的效应。结果表明：在毛竹林内施肥可使出笋数和活笋数提高3倍以上,但对竹笋(幼竹)的个体大小却几乎没有改良效果。竹笋的存活率基本上是恒定的,不随施肥量的改变而改变。当地下茎(竹鞭)穿越养分分布不均的环境时,竹笋能有选择地大量长于养分丰富的地段而避开养分贫乏的地段。另一方面,跨越于有利地段和不利地段的竹(笋)株间有明显的生理整合作用,而且这种生理整合在显著增加了长在不利地段的竹笋数(高收益)的同时,基本上没有减少长在有利地段的竹笋数(低耗费)。9m×9m的样方已足以观测到显著的施肥效果,这比传统的毛竹研究中使用的1亩的样方面积效率要高。在竹林培育方面,不均匀施肥如带状或点状施肥要比均匀施肥效率高。     

土壤铅胁迫对地被竹出笋成竹的影响研究

以6种地被竹(菲黄竹、菲白竹、铺地竹、美丽箬竹、白纹椎谷笹和狭叶倭竹)为材料,设计3个土壤铅浓度处理(0、300、1500mg·kg^-1),研究土壤铅胁迫对地被竹出笋成竹数量和新竹抗逆生理特性的影响,并采用隶属函数法对地被竹出笋成竹期的土壤铅耐受性进行综合评价。结果表明:(1)土壤铅胁迫对地被竹笋期节律的影响主要出现在出笋盛期(4~5月),发笋数的降低会导致多数竹种退笋率下降,以稳定新竹数量,只有菲白竹、白纹椎谷笹、狭叶倭竹的新竹数在高浓度土壤铅胁迫下显著低于CK,降幅分别为15.87%、23.64%和31.25%。(2)土壤铅胁迫会普遍引起地被竹新竹超氧阴离子和丙二醛含量的增加,在高浓度铅胁迫下铺地竹中二者含量最低(9.96μg·g^-1、0.016μmol·g^-1),狭叶倭竹的超氧阴离子含量最高(15.99μg·g^-1),菲黄竹的丙二醛含量最高(0.021μmol·g^-1)。(3)与其余4个竹种不同,在土壤铅胁迫下白纹椎谷笹和狭叶倭竹不能显著积累游离脯氨酸,细胞渗透调节作用弱。(4)6种地被竹在出笋成竹期对高浓度土壤铅的耐受性排序为:美丽箬竹(0.79)>铺地竹(0.75)>菲白竹(0.70)>狭叶倭竹(0.49)>白纹椎谷笹(0.39)>菲黄竹(0.38),其中美丽箬竹、铺地竹和菲白竹出笋成竹数量正常,且具有较强的抗逆生理特性,具有在高浓度土壤铅污染地区应用的潜力。     

撑绿杂交竹和硬头黄竹克隆生长特性比较

以撑绿杂交竹(Bambusa pervariabilis × Dendrocalamopsis daii)和硬头黄竹(Bambusa rigida)为研究对象, 探讨了两种丛生竹生物量分配及克隆生长特性。结果表明, 硬头黄竹秆生物量比例显著高于撑绿杂交竹, 枝和叶生物量比例显著低于撑绿杂交竹, 硬头黄竹具有更高的养分同化效率。硬头黄竹与撑绿杂交竹的繁殖率无明显差异, 但其退笋率显著低于撑绿杂交竹, 表明硬头黄竹具有更高的繁殖效率。此外, 与撑绿杂交竹相比, 硬头黄竹的成竹根茎更长, 资源开拓性更强。两种丛生竹的新竹生长与母竹数量、大小和年龄结构具显著相关性。硬头黄竹产生的竹笋质量高, 具有较高的成竹率, 生长策略类似K对策; 撑绿杂交竹产生的竹笋数量多, 但退笋率较高, 类似r对策。硬头黄竹和撑绿杂交竹的成竹数(成竹胸径)与母竹数量(母竹胸径)间存在线性相关关系, 可以用线性模型模拟。     

冠层高度对毛竹叶片光合生理特性的影响

借助LI-6400便携式光合作用系统,研究了冠层高度对不同林龄毛竹(Phyllostachys pubescens)叶片光合生理特性和水分利用效率(WUE)的季节性影响,为促进毛竹林碳汇能力和生产力提升的林分结构调整等可持续栽培技术提供理论依据。结果表明:(1)出笋期,不同竹龄毛竹叶片净光合速率(Pn)和蒸腾速率(Tr)的日均值呈现出冠层上部小于冠层下部的梯度变化趋势,且2a生毛竹不同冠层Pn日均值大于3a生毛竹;孕笋行鞭期,不同林龄毛竹各时间点Pn值和日均值、以及2年生毛竹各时间点的Tr值均为冠层上部大于冠层下部。各生长季节,不同林龄毛竹个体叶片的气孔导度(Gs)均与Tr的变化趋势一致。(2)2年生毛竹各季节仅冠层上部叶片会出现"光合午休",而3年生毛竹仅于出笋期时各冠层叶片出现"光合午休"现象。(3)出笋期毛竹叶片WUE日均值随着冠层高度增加而增加,这种变化趋势不受竹龄影响;而孕笋行鞭期,仅2年生毛竹叶片WUE日均值随着冠层高度增加而下降。不同冠层高度的孕笋行鞭期毛竹叶片WUE日均值都显著高于出笋期;冠层高度对毛竹叶片气体交换特性和WUE的影响受生长发育关键期的季节因素影响,且毛竹叶片WUE与Gs之间存在负相关关系,其不受毛竹个体年龄和叶片冠层高度影响。(4)不同生长季节各冠层叶绿素a/b值均随着冠层高度下降而降低,不同林龄毛竹叶片叶绿素含量基本随着冠层自上而下呈逐渐增加的趋势。各生长季节,不同林龄个体叶片氮素含量、比叶重随冠层高度垂直变化趋势与叶片Pn日均值的垂直变化趋势一致。研究认为,毛竹不同冠层部位叶片通过改变形态、氮素含量来适应不同生长季节生长环境的变化,以便充分利用光能提高光合能力。     

Interactions Between Shoot Age Structure, Nutrient Availability and Physiological Integration in the Giant Bamboo Phyllostachys pubescens

Abstract: The age structure of adult shoots, the nutrient availability of the habitat, and their interaction, are important factors influencing the productivity of bamboo groves. In a field fertilization experiment over two years we examined the impact of physiological integration on the emergence, growth, and survival of new shoots of Phyllostachys pubescens, a giant woody bamboo. Impacts of physiological integration were compared using uniform and patchy fertilization treatments. The number of new shoots emerging per plot significantly increased with the application of fertilizer (NPK), but the increase was constrained by the age structure of adult shoots. In a year with a high proportion of shoots with new (first-year) leaves many more new shoots emerged than in a year with a low proportion of new leaves. Mean survivorship of the new shoots was constant at 20 % for all treatments in both years of study. Surprisingly, fertilization did not increase DBH or height of the new shoots, suggesting that shoot size was fixed early in ontogeny. The pattern of fertilizer application, either uniform or patchy, did not affect the total number of new shoots produced. In the case of patchy application, more new shoots developed in unfertilized patches in comparison to uniformly unfertilized plots, probably because these parts of the clone received resources via the rhizomes from the adult shoots in adjacent fertilized patches. The production of new shoots in fertilized patches, in turn, was lower than that in uniformly fertilized plots as a result of this physiological integration. The results are discussed in the general context of the impact of integration on clonal plant performance in dense stands.     

Density-dependent growth responses in two clonal herbs: regulation of shoot density

Summary It has been shown in clonal perennial herbs that shoot natality decreases, and shoot mortality increases, in stands of increasing density. In a two-year garden experiment, we have tested Hutchings' (1979) hypothesis that these responses are the result of physiological integration, i.e. the exchange of resources and growth substances between shoots of a single clone. Dense monocultures of two rhizomatous graminoids, Brachypodium pinnatum and Carex flacca, were created that differed more than 10-fold in the density of clones (genets), but that had similar densities of shoots. A more effective shoot density control was expected in stands with the smaller clone densities (larger clones) due to more extensive clonal connections. Shoot turnover was evaluated by counting living and dead shoots at different times. In the summer of the second year, when shoot densities and stand structure were similar between treatments, shoot natality (the number of shoots born per plot) and shoot mortality (the number of shoots that died per plot) were usually unrelated to clone density in either species. If there was a significant treatment effect, it could be attributed to (small) differences in shoot density. Over the whole range of shoot densities, natality was negatively density-dependent. The number of shoots that died in a given growth period was proportional to the number of shoots present, suggesting that mortality rates were density independent. In Carex, however, there were some indications that mortality rate increased with increasing density. Our study confirms that clonal herbaceous species can effectively prevent an overproduction of shoots, but in contrast to Hutchings' (1979) propositions, we found no evidence that physiological integration may be the responsible mechanism. An alternative explanation for the observed patterns is proposed.     

Variation in shoot mortality within crowns of severely defoliated <Emphasis Type="Italic">Betula maximowicziana</Emphasis> trees in Hokkaido,northern Japan

To clarify mortality patterns of current-year shoots within the crown of Betula maximowicziana Regel after severe insect herbivory in central Hokkaido, northern Japan, we investigated the degree of defoliation, pattern of shoot development, shoot mortality, and leaf tissue-water relations. One hundred current-year long shoots growing in a B. maximowicziana plantation were observed for defoliation and mortality in June 2002. An outbreak of herbivorous insects (Caligula japonica and Lymantria dispar praeterea) occurred in the stand in mid-to-late June, and the monitored shoots were defoliated to various degrees. Within 1 month of defoliation, some of the severely defoliated shoots had produced new leaves on short shoots that had emerged from axillary buds. Stepwise logistic regression revealed that the probability that current-year long shoots would put out axillary short shoots with leaves is closely related to the degree of defoliation. To evaluate the water relations of the leaves, we determined pressure–volume curves for the leaves that survived the herbivorous insect outbreak and the new leaves that emerged after defoliation. The water potential at turgor loss (Ψ_l,tlp) and the osmotic potential at full turgidity (Ψ_π,sat) were higher for the new leaves than for the surviving leaves, indicating a lower ability to maintain leaf cell turgor against leaf dehydration in the new leaves. Of the 100 shoots, 13 died after the emergence of new leaves. Stepwise logistic regression revealed that the probability that the long shoots would die generally increased with the emergence of new leaves, with increasing shoot height. This result suggests that the combined effect of the vulnerability of newly emerged leaves and low water availability, associated with higher shoot positions within the crown, caused shoot mortality. Based on our results, some possible mechanisms for mortality in severely defoliated B. maximowicziana are discussed.     

毛竹（Phyllostachys pubescens）竹笋群动态的研究

 本文从克隆植物生长的调节与适应的角度,研究了毛竹竹笋群的时空动态。竹笋的单位面积产量及个体大小在年际之间变化很大。环境有利的年份出土的竹笋要比条件恶劣的年份多得多、高得多、壮得多。而且,自始至终较早的同生群的竹笋总比较晚的同生群的要高得多、壮得多。较早的同生群的竹笋刚出土时要经历一段生长缓慢的时期,而较晚的同生群的竹笋一出土生长就十分迅速。不管竹笋何时出土,它们几乎都同时进入最快生长期。竹笋高度日增量最快时可达每天100cm左右。本文解释了亚热带竹子在春季不同时间出土的竹笋为何及如何几乎同时抵达林冠顶部。最后,提出了一些有利于竹林经营管理的建议。     

相岭山系大、小熊猫主食竹类峨热竹的生长发育与环境因子间的相互关系

1994～1996年,在相岭山系冕宁县治勒自然保护区设点,对大熊猫和小熊猫主食竹类峨热竹与其它环境生态因子间的相互关系进行了长达3a的研究。研究结果表明,峨热竹的生长发育与环境生态因子如海拔、郁闭度、坡度和坡向之间有极其显著的相关关系,环境因子对其株高、基径、密度、发笋率、老笋比例和成竹死亡率等有较大的影响。随海拔高度的增加,竹子变矮变细,老笋比例下降;上层乔木郁闭度增加,竹子变稀,发笋率、老笋比例和成竹死亡率均降低。坡度增大,竹子变稀并且细而矮。阳坡的竹子率发笋高于阴坡。     

Carbon and nutrient dynamics in relation to growth rhythm in the giant bamboo Phyllostachys pubescens

The carbon and nutrient dynamics in relation to growth rhythm in the giant bamboo Phyllostachys pubescens on Mount Jinyun, Chongqing, China, was studied during 1993–1996. Concentrations of TNC (total non-structural carbohydrates), N, P, and K all showed the same distribution pattern among organs: leaves > branches rhizomes stems roots. The rapid spring growth of new shoots noticeably reduced the concentration of TNC in the rhizomes, in which a large amount of carbohydrates was stored. The N concentration of the rhizomes did not decrease, however. Nutrient concentration of new (1st-year) leaves was significantly higher than that of old (2nd-year) leaves. Although the density of adult shoots was almost the same during 1994–1996, the low ratio of the number of adult shoots with new to that with old leaves from June 1994 to April 1995 resulted in a low TNC concentration in the rhizomes in early spring (April) 1995. This led to a low production of new shoots in the spring of 1995, their number being only ca. 10% of that in 1994 and 1996. Before old leaves were shed, a large amount of nutrients was remobilized and translocated to other plant parts to support further growth. Fertilization with NPK significantly increased the concentrations of N and P in leaves and subsequently increased the number of emerging new shoots.     

Ambulatory migration in mites (Acari: Tetranychidae, Phytoseiidae) to new leaves of moso bamboo shoots

The migratory behaviour of two tetranychid pest species, Aponychus corpuzae and Schizotetranychus nanjingensis, and one phytoseiid, Typhlodromus bambusae, was studied in several monocultural bamboo forests in Fujian Province, China. The aim of the study was to assess how the ambulatory immigration of tetranychid and phytoseiid mites from the ground to new leaves is affected by a sticky barrier around the stem, by the age of bamboo shoots or by shoot density. The results show that while the sticky barrier is particularly effective at disrupting the ambulatory immigration from the ground to new leaves of S. nanjinigensis to 1-year-old shoots and of A. corpuzae to 3-year-old shoots, it has no significant effect on the immigration of the phytoseiid mite.     

Clone-specific response of Festuca rubra to natural variation in biomass and species composition of neighbours

A long-term implant experiment with four clones of Festuca rubra was performed to identify fine-scale spatial variation in a competitive environment within a grassland sward of natural composition and density variation. Total above-ground biomass and shoot counts of all species were recorded in 10×10 cm neighbourhoods of each implant, and their effect on the growth response of the implant was tested. Two types of response were recorded: (1) shoot sizes and vertical shoot growth dynamics, and (2) horizontal space encroachment by means of new shoot natality, mortality and their mode of formation (intravaginal or extravaginal). The vertical growth of individual shoots showed the strongest response to neighbourhood composition; it responded to the overall aboveground biomass of the neighbours, but not to their species composition. The responses in parameters of horizontal growth of individuals (natality, mortality, proportion of extravaginal shoots) were much weaker and not consistent over the observation period; however, both total biomass of the neighbours and species composition affected the response of the target plants.
The overall response was rather weak in spite of a tenfold variation in neighbouring density and a thirtyfold variation in neighbouring biomass. This indicates that the response to this variation is rather flat under field conditions, either due to high overall values of density or due to interactions with below-ground processes. Consequently, though the plant is capable of remarkable plastic responses in both vertical growth and morphogenetic change, under field conditions this capacity for plastic response is expressed only to a limited degree.