人工油松林的化学元素特征

28年生人工油松林的建群种——油松各器官化学元素浓度由叶、小枝、枝和树干逐渐下降。叶内元素浓度高低,以碳、氮、钙、钾、镁、磷为序。地下部分细根较粗根的元素浓度为大。灌木的化学元素的共同特点是碳含量最高,其次为氮、钾和钙。灌木叶片中的元素浓度大于茎。草本植物地上部分元素浓度明显低于灌木叶。灌木根系内化学元素浓度均低于它的地上部分。枯枝落叶的化学成分与活的枝、叶相比,铁的浓度显著增加,其次为铝,其他元素的浓度或多或少有所下降。在人工油松林各层次植物中,以碳素积累量最高,其次为钙和氮。元素的存留量仍以碳素为高,其次在乔木层中存留量以钙较大,在灌木层中以氮、钾较高。元素的年归还量除碳以外,钙较高,钾、磷较低。人工林的吸收量/土壤贮量的比值,以钾和磷较高。土壤中代换性钾、磷的贮量相对不大,为促进人工林生长,增施磷肥和钾肥将是有效的。     

氮、磷、钾对豫麦50旗叶蔗糖和籽粒淀粉积累的影响

以豫麦50为对象,探讨了氮、磷、钾对小麦旗叶中蔗糖的积累及相关酶活性以及籽粒中淀粉含量和组分的影响.结果表明,施氮可以增加灌浆前期旗叶中的糖含量,施钾则提高了灌浆后期旗叶中的糖含量,而施磷则对旗叶中的糖含量影响不大.施氮、磷、钾均能增加蔗糖合成酶活性,但它们的作用时间不同：施氮活性增加在籽粒灌浆中期,施磷在灌浆前期,而施钾在灌浆前、中期.但氮亦可增加花后24 d的磷酸蔗糖合成酶活性,施磷增加了灌浆前、中期磷酸蔗糖合成酶活性,施钾则增加了灌浆后期旗叶磷酸蔗糖酶活性.施氮、磷、钾都提高了籽粒中总糖含量,增加籽粒中淀粉含量,其中施钾效果最为明显.施磷提高籽粒中直链淀粉的积累,而施钾则显著提高了籽粒中支链淀粉的含量.     

氮磷钾肥对地道药材建泽泻生长与品质的影响

通过田间正交试验并结合室内HPLC分析,研究了氮、磷和钾素营养对建泽泻〔Alisma orientale(Sam.)Juzepcz.〕生长和品质的影响。结果表明,施用基肥对建泽泻生长前期的叶片数、株高、叶宽和叶长等农艺性状的影响均大于不施基肥处理;氮、磷和钾施用量对建泽泻产量均无显著影响,当施肥量为纯N 225.0 kg.hm-2、P2O5187.5 kg.hm-2和K2O 225.0 kg.hm-2,总施肥量为637.5 kg.hm-2时,产量最高;氮、磷和钾施用量对建泽泻块茎的粒重均无显著影响;磷的施用量对建泽泻指标性成分23-乙酰泽泻醇B含量有显著影响,而氮和钾均没有显著影响,且影响作用从高至低次序依次为P2O5、N、K2O。     

氮、磷、钾对美洲斑潜蝇寄主选择性的影响

研究了不同浓度的氮、磷、钾营养液处理豇豆叶对美洲斑潜蝇Liriomyza sativae寄主选择性的影响,并探讨了其可能的机理和应用。     

钩梢强度对麻竹生物量分配和生理特性的影响

以不钩梢为对照,对笋期内麻竹进行轻度、中度、重度钩梢处理,研究各钩梢处理立竹构件生物量分配、当年生枝条和商品叶生长,以及净光合速率(P_n)、蒸腾速率(T_r)、水分利用效率(WUE)和叶片水势(LWP)等的变化,分析麻竹对营林措施中钩梢强度的适应机制和生存策略.结果表明: 与对照相比,钩梢处理对麻竹生物量及分配影响显著,3个处理麻竹立竹的叶/枝、叶/秆、枝/秆生物量比均显著高于对照.轻度钩梢和中度钩梢处理当年生枝条数量、基径、长度均显著大于对照,其中,中度钩梢处理当年生枝条基径、数量、长度和商品叶数量分别比对照增加43.0%、53.3%、29.8%和39.5%.各钩梢处理麻竹P_n、T_r、WUE、LWP在笋期内大小为出笋盛期>末期>初期;钩梢后麻竹的P_n、T_r和WUE显著提高,其中,各处理出笋盛期和末期的P_n大小为中度钩梢>轻度钩梢>重度钩梢>对照,且出笋盛期和末期的P_n分别是对照的1.4和1.3倍.各处理出笋初期、盛期和末期的T_r均为重度钩梢>中度钩梢>轻度钩梢>对照.中度钩梢处理对麻竹立竹的生物量分配、商品叶产量和生理特性均有明显优势,并能有效提高麻竹立竹的水分可获得性.     

吊丝单竹笋期叶片特性研究

对3种不同年龄的吊丝单竹株在不同发笋时期、不同竹冠部位的叶片比叶重、光合、呼吸性状及N、P、K含量等进行测定,结果表明:吊丝单竹在不同发笋时期、不同竹冠部位各项指标均有较大差异。比叶重发笋盛期高于初期和末期,随着竹株年龄增大而减小,随着竹冠的升高而增大;净光合速率盛期高于初期,光呼吸速率和暗呼吸速率则初期高于盛期,并且不同竹龄、不同竹冠部位之间均表现出较大的差异;N、P、K含量由发笋初期至盛期逐渐减小,N含量以1a>2a>3a,以竹冠中部最高,P、K含量则随着竹冠的升高而减小,随着竹株年龄的增大而增大。这为经营管理吊丝单竹林提供科学依据。     

茄子无土栽培氮磷钾浓度优化施肥方案

本试验采用三因子二次饱和D-最优设计(310),以蛭石为栽培介质,建立了以氮、磷、钾浓度为变量因子,茄子产量和品质为目标函数的三元二次数学模型,以期得到茄子优质高产最优氮磷钾浓度范围.对模型解析结果表明: 氮、磷、钾浓度对茄子产量和品质均有显著影响.对产量和品质的影响程度均以钾浓度较大,对产量的影响程度以氮浓度次之,磷浓度较小,对品质则为磷浓度次之,氮浓度较小.氮磷、氮钾、磷钾浓度交互对茄子产量均有显著影响;氮钾浓度交互对茄子品质亦有显著影响.在低水平条件下,茄子产量和品质均随氮、磷、钾浓度增加而增加,但超过一定范围后,茄子产量和品质均随之降低.通过计算机模拟运算得出,本试验条件下茄子单株产量达3600 g的施肥方案为:氮16.0～20.0 mmol·L^-1、磷2.2～2.6 mmol·L^-1、钾9.9～12.9 mmol·L^-1;品质综合评分在90分以上的施肥方案为:氮18.0～21.1 mmol·L^-1、磷1.9～2.6 mmol·L^-1、钾10.6～13.3 mmol·L^-1.试验小区茄子产量预期达到43.2 kg(6个月生长期)、品质综合评分高达90分以上的优质高产营养液氮磷钾浓度范围为:氮18.0～20.0 mmol·L^-1、磷2.2～2.6 mmol·L^-1、钾10.6～12.6 mmol·L^-1,适宜的N∶P₂O₅∶K₂O浓度比例约为1∶0.13∶0.62.     

施氮量对小麦氮磷钾养分吸收利用和产量的影响

高产条件下研究了不同施氮量对小麦植株氮、磷、钾养分吸收利用及籽粒产量的影响.结果表明,适量施氮可促进小麦植株对氮素的吸收与积累,较高的施氮量不利于起身期之后的氮素积累,致使成熟期小麦氮素积累量未能显著提高;与不施氮肥相比,施氮显著提高植株磷素积累量;随施氮量增加,植株磷素积累量增加不显著;施氮量增加促进小麦生育前期对钾素的吸收积累,在生育后期降低植株钾素的流失.随施氮量增加,籽粒氮素含量呈先增后降的趋势,氮素向籽粒的分配比例趋于降低,植株氮素利用效率无显著变化,氮素收获指数下降;不同施氮处理之间籽粒磷素含量和钾素含量无显著差异,施氮量增加,营养器官钾素含量、钾素积累量和钾素向叶片的分配比例均呈增加趋势;同时,磷素和钾素利用效率降低;不同施氮处理间,植株磷素、钾素收获指数无显著差异.籽粒产量随施氮量增加呈先增加后降低的趋势,以施氮195 kg/hm2的处理籽粒产量最高.     

花粒期光照对夏玉米干物质积累和养分吸收的影响

选用登海605(DH605)为试验材料,在大田条件下通过花粒期遮阴(S)和增光(L)研究不同光照对花后夏玉米产量、干物质积累和氮、磷、钾养分吸收与运转特性的影响.结果表明: 遮阴后夏玉米产量、干物质积累量及氮、磷、钾养分吸收量均显著降低;而增光有利于夏玉米干物质积累量及氮、磷、钾养分吸收量和产量的提高.2011-2013年,遮阴处理的产量较对照(自然光下)分别降低了59.4%、79.0%、60.6%;增光后产量分别增加16.3%、12.9%、6.8%.遮阴对干物质积累的影响大于其对植株氮、磷吸收量的影响,植株体内氮、磷等养分含量有所上升,而钾吸收量的下降幅度大于干物质积累,钾素相对含量降低,氮、磷、钾向籽粒的分配比例降低.增光后干物质积累和氮、磷吸收量显著上升,但对氮、磷吸收的影响更大;增光条件下,氮、磷、钾等养分向籽粒的分配比例增加.
     

3种林木凋落物分解特征及其对赤红壤酸度及养分含量的影响

在实验室条件下对黧蒴锥[Castanopsis fissa(Champ.ex Benth.)Rehd.et Wils.]、湿地松(Pinus elliottii Engelm.)和尾叶桉(Eucalyptus urophylla S.T.Blakely)凋落物的分解特征及其对华南赤红壤的pH值、有机质和碱解氮、速效磷和速效钾含量的影响进行了研究.结果表明:经过1 a的分解后,黧蒴锥、湿地松和尾叶桉凋落物的失重率分别为26.48％、13.80％和28.15％;3种凋落物中全氮均为净释放模式,全磷为富集模式,黧蒴锥和尾叶桉凋落物中全钾和有机碳为净释放模式,湿地松凋落物中全钾和有机碳为富集模式.随凋落物分解时间的延长,土壤pH值呈现逐渐上升至第8个月达到峰值、之后略有下降的变化趋势;有机质含量呈波动的变化趋势;碱解氮含量呈先升高后降低的变化趋势;速效磷含量呈略有波动但总体下降的趋势;速效钾含量呈“逐渐上升—急剧下降—急剧上升—趋于平稳”的变化趋势,且均在第8个月最低.与实验初期相比,实验结束时对照组及各处理组的土壤pH值和碱解氮含量均不同程度增加、有机质含量不同程度降低、速效磷含量显著下降,对照组速效钾含量下降而各处理组速效钾含量明显提高.与对照相比,实验结束时3种凋落物均导致土壤酸度减弱、速效钾含量增加、但有机质和速效磷含量没有明显提高.3种凋落物对土壤pH值及土壤养分含量的影响有明显差异,总体上看,黧蒴锥凋落物覆盖可明显减弱土壤酸度,增加土壤有机质、碱解氮和速效钾含量,对土壤的改良效果最好.研究结果揭示:不同凋落物对土壤pH值及养分含量的影响与凋落物的成分及生物学特性有关.     

山地麻竹林生态系统养分分配格局

通过对不同年龄和器官山地麻竹养分垂直分布及生态系统现存养分分配格局研究 ,结果表明 :麻竹地上器官各养分浓度随高度的升高有增加的趋势 ;在竹林层中 ,各年龄单株麻竹地下器官含量低于地上部分 ,但 N、Ca、Si O2 养分现存总量高于地上部分 ,P、K低于地上部分器官总量 ;各养分在竹秆不同高度含量不同 ,呈现随高度增加而减少的变化规律 ,竹枝和竹叶养分量随高度的分配呈现“小 -大 -小”的变化规律 ,但两个年度麻竹养分量最大值出现的高度不同 ;不同年龄麻竹单株养分含量都以幼竹为最小 ,1年生麻竹 N、P、K含量高于 2年生麻竹 ,但 Ca、Si O2 含量低于 2年生麻竹 ;地下器官中 ,竹蔸各种养分含量高于根。在群落中 ,各种养分都以麻竹林层占绝对优势 ,N、P、K、Ca、Si O2 分别占群落养分的 89.0 931%、89.0 2 4 7%、89.5 0 2 7%、93.186 7%和 88.4 135 % ,凋落物层养分其次 ,林下植被层最低     

The functional ecology of shoot architecture in sun and shade plants of Heteromeles arbutifolia M. Roem., a Californian chaparral shrub

The functional roles of the contrasting morphologies of sun and shade shoots of the evergreen shrub Heteromeles arbutifolia were investigated in chaparral and understory habitats by applying a three-dimensional plant architecture simulation model, YPLANT. The simulations were shown to accurately predict the measured frequency distribution of photosynthetic photon flux density (PFD) on both the leaves and a horizontal surface in the open, and gave reasonably good agreement for the more complex light environment in the shade. The sun shoot architecture was orthotropic and characterized by steeply inclined (mean = 71^o) leaves in a spiral phyllotaxy with short internodes. This architecture resulted in relatively low light absorption efficiencies (E _A) for both diffuse and direct PFD, especially during the summer when solar elevation angles were high. Shade shoots were more plagiotropic with longer internodes and a pseudo-distichous phyllotaxis caused by bending of the petioles that positioned the leaves in a nearly horizontal plane (mean = 5^o). This shade-shoot architecture resulted in higher E _A values for both direct and diffuse PFD as compared to those of the sun shoots. Differences in E _A between sun and shade shoots and between summer and winter were related to differences in projection efficiencies as determined by leaf and solar angles, and by differences in self shading resulting from leaf overlap. The leaves exhibited photosynthetic acclimation to the sun and the shade, with the sun leaves having higher photosynthetic capacities per unit area, higher leaf mass per unit area and lower respiration rates per unit area than shade leaves. Despite having 7 times greater available PFD, sun shoots absorbed only 3 times more and had daily carbon gains only double of those of shade shoots. Simulations showed that sun and shade plants performed similarly in the open light environment, but that shade shoots substantially outperformed sun shoots in the shade light environment. The shoot architecture observed in sun plants appears to achieve an efficient compromise between maximizing carbon gain while minimizing the time that the leaf surfaces are exposed to PFDs in excess of those required for light saturation of photosynthesis and therefore potentially photoinhibitory. Received: 8 June 1997 / Accepted: 2 November 1997     

Acclimation of Myrtus communis to contrasting Mediterranean light environments - effects on structure and chemical composition of foliage and plant water relations

Leaf anatomical and chemical characteristics, water relations and stomatal regulation were studied in the shrub Myrtus communis growing under two contrasting Mediterranean light environments (full light versus 30% of full light) during the spring-summer period. These studies aimed to assess plant response to the combined effects of light and water availability. Foliar morphology, anatomy and chemistry composition acclimated positively to light conditions. Leaves of sun-exposed plants were thicker (38.7%) than those of shaded plants, mainly due to increased palisade parenchyma thickness, had a higher nitrogen concentration and stomatal density than the shade ones, which maximized foliar area (>SLA) and Chl/N molar ratio to improve light interception. Chlorophyll concentration per leaf area (Chl(a)) was always higher in sun leaves while, as expressed on dry mass (Chl(m)), significant differences were only apparent in September, shade leaves presenting higher values. During the summer period Chl(a) and Chl(m) markedly declined in sun leaves and remained unchanged in shade ones. The ratio of chlorophyll a/b was not affected either by the light intensity or by the season. Shade leaves presented generally a higher concentration of soluble carbohydrates per dry mass. No significant differences in starch concentration were apparent between sun and shade leaves and a gradual depletion occurred during the water stress period. Maximum stomatal conductances correlated positively with predawn water potential. Throughout the season, sun plants always presented higher leaf conductance to water vapour and lower minimum leaf water potentials, indicating an interaction of light-environment on these water relation parameters. Stomatal closure constitutes a mechanism to cope with diurnal and seasonal water deficits, sun plants presenting a more efficient control of water losses during water deficiency period. In addition, both sun and shade plants evidenced leaf osmotic adjustment ability in response to water stress, which was greater in sun ones.     

桂平市竹笋资源及其开发利用

桂平市食用竹笋资源丰富,有大头竹笋、吊丝竹笋、浦竹笋、毛竹笋等十余种,年产鲜笋８５００ｔ以上。原有的加工方法比较落后,现已注意引进新技术,今后还需进一步开发利用。     

CHANGES IN NUTRIENT CONTENT OF PALMARIA PALMATA IN RESPONSE TO VARIABLE LIGHT AND UPWELLING IN NORTHERN SPAIN1

Light has been identified as one of the main factors affecting seaweed ecophysiology. We investigated the dependence of nutrient metabolism on sun and shade light conditions and whether episodes of upwelling of nutrient‐rich subsuperficial water could reduce the summer nutrient limitation driving physiological changes in Palmaria palmata (L.) Kuntze. We measured the major nutrient pools, photosynthetic pigments, and light curves, under sun and shade conditions during a summer period when one upwelling was recorded. The redundancy analysis (RDA) produced two clear groups: sun‐ and shade‐acclimated algae. Light was the major predictive factor. Sun‐acclimated algae exhibited higher carbon (C) and lower nitrogen (N) and phosphorus (P) content in association with the storage of floridoside (main C reserve) to benefit from higher irradiance (under nutrient limitation). Among N pools, N reserves (phycoerythrin, nitrate) were a lower proportion of the total N in sun‐acclimated algae, suggesting their degradation to fulfill the N demands of the cell. The orthophosphate content was also lower in sun‐acclimated algae, indicating its utilization as a nutrient reserve. In contrast, N within cell walls and membranes and chl a contributed to a similar proportion of the total N in sun‐ and shade‐acclimated algae, suggesting a response to sustain cell integrity. Transient high nutrient concentration due to the upwelling was unrelated to the nutrient content of the thallus. The storage of C as floridoside from high light exposure was shown to be the driving force for the metabolic adjustment of P. palmata at the end of summer before the onset of dormancy.     

Effect of local irradiance on CO(2) transfer conductance of mesophyll in walnut

The acclimation responses of walnut leaf photosynthesis to the irradiance microclimate were investigated by characterizing the photosynthetic properties of the leaves sampled on young trees (Juglans nigraxregia) grown in simulated sun and shade environments, and within a mature walnut tree crown (Juglans regia) in the field. In the young trees, the CO(2) compensation point in the absence of mitochondrial respiration (Gamma*), which probes the CO(2) versus O(2) specificity of Rubisco, was not significantly different in sun and shade leaves. The maximal net assimilation rates and stomatal and mesophyll conductances to CO(2) transfer were markedly lower in shade than in sun leaves. Dark respiration rates were also lower in shade leaves. However, the percentage inhibition of respiration by light during photosynthesis was similar in both sun and shade leaves. The extent of the changes in photosynthetic capacity and mesophyll conductance between sun and shade leaves under simulated conditions was similar to that observed between sun and shade leaves collected within the mature tree crown. Moreover, mesophyll conductance was strongly correlated with maximal net assimilation and the relationships were not significantly different between the two experiments, despite marked differences in leaf anatomy. These results suggest that photosynthetic capacity is a valuable parameter for modelling within-canopies variations of mesophyll conductance due to leaf acclimation to light.     

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。     

Phenotypic plasticity in response to light in the coffee tree

Phenotypic plasticity to light availability was examined at the leaf level in field-grown coffee trees (Coffea arabica). This species has been traditionally considered as shade-demanding, although it performs well without shade and even out-yields shaded coffee. Specifically, we focused our attention on the morpho-anatomical plasticity, the balance between light capture and excess light energy dissipation, as well as on physiological traits associated with carbon gain. A wide natural light gradient, i.e., a diurnal intercepted photon irradiance differing by a factor of 25 between the deepest shade leaves and the more exposed leaves in the canopy, was explored. Responses of most traits to light were non-linear, revealing the classic leaf sun vs. leaf shade dichotomy (e.g., compared with sun leaves, shade leaves had a lower stomatal density, a thinner palisade mesophyll, a higher specific leaf area, an improved light capture, a lower respiration rate, a lower light compensating point and a limited capacity for photoprotection). The light-saturated rates of net photosynthesis were higher in sunlit than in shade leaves, although sun leaves were not efficient enough to use the extra light supply. However, sun leaves showed well-developed photoprotection mechanisms in comparison to shade leaves, which proved sufficient for avoiding photoinhibition. Specifically, a higher non-photochemical quenching coefficient was found in parallel to increases in: (i) zeaxanthin pools, (ii) de-epoxidation state of the xanthophyll cycle, and (iii) activities of some antioxidant enzymes. Intracanopy plasticity depended on the suite of traits considered, and was high for some physiological traits associated with photoprotection and maintenance of a positive carbon balance under low light, but low for most morpho-anatomical features. Our data largely explain the successful cultivation of the coffee tree in both exposed and shade environments, although with a poor resource-use efficiency in high light.     

Responses of leaf structure and photosynthetic properties to intra-canopy light gradients: a common garden test with four broadleaf deciduous angiosperm and seven evergreen conifer tree species

Spectra of leaf traits in northern temperate forest canopies reflect major differences in leaf longevity between evergreen conifers and deciduous broadleaf angiosperms, as well as plastic modifications caused by within-crown shading. We investigated (1) whether long-lived conifer leaves exhibit similar intra-canopy plasticity as short-lived broadleaves, and (2) whether global interspecific relationships between photosynthesis, nitrogen, and leaf structure identified for sun leaves adequately describe leaves differentiated in response to light gradients. We studied structural and photosynthetic properties of intra-tree sun and shade foliage in adult trees of seven conifer and four broadleaf angiosperm species in a common garden in Poland. Shade leaves exhibited lower leaf mass-per-area (LMA) than sun leaves; however, the relative difference was smaller in conifers than in broadleaves. In broadleaves, LMA was correlated with lamina thickness and tissue density, while in conifers, it was correlated with thickness but not density. In broadleaves, but not in conifers, reduction of lamina thickness was correlated with a thinner palisade layer. The more conservative adjustment of conifer leaves could result from a combination of phylogenetic constraints, contrasting leaf anatomies and shoot geometries, but also from functional requirements of long-lived foliage. Mass-based nitrogen concentration (N(mass)) was similar between sun and shade leaves, and was lower in conifers than in deciduous broadleaved species. Given this, the smaller LMA in shade corresponded with a lower area-based N concentration (N(area)). In evergreen conifers, LMA and N(area) were less powerful predictors of area-based photosynthetic rate (A (max(area))) in comparison with deciduous broadleaved angiosperms. Multiple regression for sun and shade leaves showed that, in each group, A (max(mass)) was related to N(mass) but not to LMA, whereas LMA became a significant codeterminant of A (max(mass)) in analysis combining both groups. Thus, a fundamental mass-based relationship between photosynthesis, nitrogen, and leaf structure reported previously also exists in a dataset combining within-crown and across-functional type variation.     

土壤垦复对山地麻竹林地表养分流失动态的影响

为了比较山地麻竹笋用林不同土壤垦复措施对养分流失动态的影响,在福建南靖国有林场设置径流场,进行了1年的观测、取样和氮磷钾浓度分析.结果表明,3种土壤垦复措施的氮、磷、钾流失量具有明显的季节性,4～9月3种养分流失量占全年90%以上,且都呈现全翻>带翻>对照,但3种经营措施间氮、磷的年流失量差异均不显著,全翻的钾流失量差异水平达显著,带翻与对照间差异不显著.