Effects of simulated nitrogen deposition on fine root morphology,nitrogen and phosphorus efficiency of Pinus massoniana clone under phosphorus deficiency

Aims In forest ecosystems with phosphorus (P) deficiency, the impact of atmospheric nitrogen (N) deposition on nutritional traits related to N and P uptake potentially affect plant growth and vegetation productivity. The objective of this study was to explore the effects of simulated N deposition on fine root morphological characteristics and effiency of N and P absorption in Pinus massoniana under under low P stress.
Methods Two clones of P. massoniana seedling with different P efficiency (high P efficiency 19-5 vs. low P efficiency 21-3) were used. A two-year pot experiment was applyed with treatments of two P conditions, (i.e. homogeneous low P availability vs. heterogeneous low P availability) and three N deposition levels (0, 30 and 120 kg N·hm^-2·a^-1; i.e., N0, N30, or N120, respectively) .
Important findings 1) The growth of P. massoniana seedling was interactively affected the three factors: simulated N deposition, P condition and genotypes. Simulated N deposition increased the seedling height and dry mass under heterogeneous P deficiency, but did not significantly affect those traits under homogeneous P deficiency. Under heterogeneous P deficiency and N120 treatment, the seedling height and dry mass of clone 19-5 were 1.1 times and 1.6 times higher than that of clone 21-3, respectively. 2) Fine root length and surface area decreased as root diameter increased. N deposition significantly stimulated proliferation of fine root with diameter ≤1.5 mm, while roots with diameters ranged from 1.5 to 2.0 mm and over 2.0 mm were not influenced. The length of fine root ≤1.5 mm in diameter accounted for 90.4%-92.8% of the total root length and was not affected by N deposition. 3) Under the heterogeneous low P condition, clone 19-5 was found to respond to the simulated N deposition with increased root length and surface area in fine-root diameter class of ≤1.5 mm. Additionally, in compared with control, its N and P absorption efficiency were significantly enhanced 93.3% and 148.4%, respectively under N120 treatment. However, the N and P absorption efficiency of clone 21-3 was less affected by the simulated N deposition. The N and P use efficiency had no notable variation. Finally, we found that the proliferation of fine-root ≤1.5 mm in diameter and high N (P) absorption efficiency maybe the adaptive mechanisms of P. massoniana responding to atmospheric N deposition under P deficiency.     

5种栎树幼苗对铅锌尾矿砂的耐性与植被恢复前景

通过盆栽试验,评价栎属植物在铅锌尾矿中的生长响应及植被恢复前景.分析比较了覆瓦栎、猩红栎、樱皮栎、舒玛栎和白栎5种栎树幼苗在铅锌矿砂中生长30个月后的生物量、根系形态及其对营养元素和重金属的吸收及转移特征.结果表明: 5种栎树在矿砂中均能生长,其中,猩红栎和白栎的生物量较对照有下降趋势,其他3种栎树的生长与对照相比无显著差异;栎树根系生物量均较对照有不同程度增加(猩红栎除外),且仅猩红栎侧根形态学参数较对照有所减少.重金属胁迫下,栎树根系和茎中营养元素浓度较对照无显著变化.5种栎树体内重金属浓度均较低,且其生物富集系数和转移系数均小于1.但樱皮栎叶片和茎中Cd浓度分别为22.4和15.1 mg·kg^-1,转移系数为2.3,显著高于其他4种栎树.除猩红栎以外,其他参试栎树均可作为有潜力的污染土壤修复树种.其中舒玛栎的耐性较高、生物富集系数和转移系数较低,是适合在尾矿区造林和生态修复的优选树种.     

不同温度条件下香水文心兰花香气的成分分析及感官评定

Flower aromatic components and their relative contents of Oncidium Sharry Baby ‘Sweet Fragrance ’ at full flowering stage under conditions of 10 ℃, 20 ℃ and 30 ℃ were analyzed by solid phase micro-extr...     

文心兰浅绿条纹突变体的生理生化及叶绿素荧光特性研究

以文心兰浅绿条纹突变体为材料,分析叶片光合色素含量和组成、叶绿素合成前体物质含量以及叶绿素荧光参数的变化,观察突变体叶绿体超微结构的改变,以探寻其叶色变异的生理基础。结果表明:(1)突变体叶绿素a(Chl a)、叶绿素b(Chl b)、类胡萝卜素(Car)和总叶绿素(Chl)含量分别比叶色正常植株显著降低了37.1%、34.0%、30.8%和36.3%。(2)突变体叶绿素生物合成受阻于胆色素原(PBG)到尿卟啉原Ⅲ(UrogenⅢ)的反应步骤。(3)突变体叶绿体发育存在明显的缺陷,基粒数目及基粒片层的垛叠层数明显减少,嗜锇颗粒及囊泡较多。(4)突变体初始荧光(Fo)比正常植株高39%,最大荧光(Fm)、最大光化学效率(Fv/Fm)、PSⅡ有效光化学效率(Fv′/Fm′)和PSⅡ实际光化学效率(ΦPSⅡ)均显著低于正常植株,但光化学淬灭系数(qP)和非光化学淬灭系数(NPQ)与正常植株无显著差异。研究结果说明,文心兰叶绿素生物合成受阻和叶绿体结构发育不良,导致叶绿素的含量下降,致使突变体叶片呈现浅绿条纹,光能利用率降低。     

不同养分环境下木荷种源生长和根系发育对邻株竞争响应的差异

研究同质和异质养分环境中邻株竞争对3个木荷种源生长和根系发育的影响,揭示了不同种源木荷生长竞争能力差异原因.结果表明: 与同质养分环境相比,3个木荷种源在异质养分环境中具有苗高生长量大、干物质积累量高和根系增生明显等特点.在异质养分环境下,福建建瓯种源木荷苗木生长量显著高于浙江龙泉和江西信丰种源,与杉木混植时尤为突出,这与其根系形态可塑性高和拓殖能力强有关,混植时,福建建瓯种源木荷的根长、根表面积和根体积等根系生长量较单植显著增长20.4 %～69.0%,其根系在富养表层大量增生的同时快速向深层贫养层拓殖,占有了更多的空间和资源,提高了觅养能力,使其生长优势更为明显,而浙江龙泉和江西信丰种源根系生长和深层土壤根系分布受邻株竞争影响不同程度的降低.纯植时,可能由于根系自我识别作用,3个木荷种源的根系生长发育均受到抑制,导致福建建瓯种源苗木生长量显著减小,而浙江龙泉种源苗高和干物质积累增长明显,这与其根系生理可塑性有关.建议生产上选用觅养效率高和竞争能力强的福建建瓯种源木荷,采用混交造林的方式提高木荷人工林生产力.     

Effects of localized nitrogen supply treatments on growth and root parameters in Pinus massoniana families under phosphorus deficiency

Aims A heterogeneous spatially distribution of nutrients in natural soil may affect plant growth. The objective of this study was to determine the effects of localized nitrogen (N) supply treatments on growth traits and root parameters among different families in Pinus massoniana.Methods Five families of P. massoniana seedlings from full-sib progenies were used as test materials (1, 25, 49, 52, and 57). This study included two conditions, (i.e. homogeneous phosphorus (P) deficiency vs. heterogeneous P efficiency) among soil layers in combination with four N supply treatments in a one-year pot experiment. These N supply treatments were: (1) Homogeneously high N along the soil profile (HHH); (2) high N-high N-low N (HHL); (3) low N-low N-high N (LLH); (4) low N-low N-on side with N addition and the other side without N supply (LLH/L).Important findings This study indicated that localized N supply treatment did enhance the growth of P. massoniana, and this enhancement mainly happened in the pattern of N applied to deep soil. The results showed: 1) Compared to the homogeneous low P condition, there were increase in the growth traits and root parameters of P. massoniana under heterogeneous low P condition. Particularly, the root length and root surface area under the heterogeneous P deficiency condition were 1.95 times and 2.11 times higher than that subjected to the homogeneous P deficiency. 2) Localized N supply treatment affected seedling growth, and there was a significant interaction among N supply pattern and P condition. In compared with homogeneous N supply treatment, the height, basal diameter and dry weight of seedlings increased significantly by localized N supply treatments (LLH and/or LLH/L) under both two P deficiency conditions. But when the seedlings parameters were enhanced under homogeneous P deficiency, they were inhibited under heterogeneous P deficiency subjected to HHL. 3) Within the two P conditions, LLH and LLH/L stimulated root proliferation significantly, and root parameters were significantly enhanced under the heterogeneous P deficiency condition. Specifically, the root length and root surface area subjected to LLH/L rather than HHH were significantly enhanced by 29.2% and 32.3%, respectively. However, the length and surface area of the roots were suppressed by HHL treatment. 4). There were significant differences in response to different N supply treatments among P. massoniana families Seedlings in the families of 49, 52, and 57 responded to the localized N supply treatments with increased root proliferation, which enhanced seedling dry mass. On the other hand, the seedling growth in the family of 25 were stimulated by N and (or) P concentration, while the response of seedlings in the family of 1 to local nitrogen supply was relatively slow and exhibited growth retardation.     

解磷菌肥不同施用方式对马尾松家系苗木根系生长及磷素营养的影响

为了探讨解磷菌肥分区施入对低磷胁迫下马尾松磷营养状况的影响，该文设置了局部和均匀施用解磷菌肥(PSB肥)的盆栽接种试验，并利用WinRHIZO Pro STD1600+根系图像分析软件、H₂SO₄-H₂O₂消煮和钼锑抗比色法研究了马尾松不同家系根系形态参数和苗木磷素吸收量对PSB肥不同施用方式的响应。结果表明：(1)局部和均匀施用PSB肥均对马尾松生长影响显著，局部施用较均匀显著增加了苗木苗高、地径、根冠比、根系和整株干物质量等主要生长指标。(2)局部施用PSB肥苗木根长、根表面积、根体积和根尖数显著增加，而均匀施用根系各参数有所增加但差异不显著；局部施用较均匀0<根系直径(D)≤0.5 mm的细根根长增加了近2倍。两种处理根系生长的差异与局部施用PSB肥造成了土壤磷素的异质性分布有关。(3)与均匀施用PSB肥相比，局部施用显著增加了苗木根、茎、叶及整株磷素吸收量。相关性分析表明，苗木磷素吸收量与根系形态参数、D≤1.0 mm根系根长呈显著正相关。说明局部施用PSB肥通过诱导根系的生长促进苗木...     

模拟氮沉降对低磷胁迫下马尾松无性系细根形态和氮磷效率的影响

根系是植物吸收土壤营养的关键部位, 不同径级根系的形态和功能差异不仅与植株自身的遗传因素有关, 而且受到土壤中营养元素分布和水平的影响。在我国亚热带高氮沉降和酸性红壤磷匮乏及不均一的土壤环境下, 研究林木不同径级根系对外界营养环境变化的响应有利于深入了解林木根系的觅养机制及规律。该文以马尾松(Pinus massoniana)无性系19-5 (高磷效率)和21-3 (低磷效率)为材料, 在同质低磷和异质低磷两种盆栽处理下, 设置3个氮水平(对照、中氮和高氮)的模拟氮沉降实验。结果表明: 1)马尾松无性系苗木的生长受磷环境、氮水平和无性系三因素共同影响, 模拟氮沉降显著促进了异质低磷下马尾松苗高和整株干物质量的增加, 而在同质低磷下氮效应不显著; 在异质低磷、高氮下, 无性系19-5的苗高和整株干物质量分别是无性系21-3的1.1倍和1.6倍。2)马尾松各径级细根长度和表面积随径级增大而减小, 模拟氮沉降促进了直径≤1.5 mm的细根的增生发育, 直径1.5-2.0 mm的细根和>2.0 mm的较粗根无明显变化; 另外, 直径≤1.5 mm的细根长度占总根长的比例保持在90.4%-92.8%范围内, 受氮影响较小。3)模拟氮沉降显著提高了异质低磷下无性系19-5≤1.5 mm的细根长度和表面积, 同时, 其根系氮、磷吸收效率较对照分别高出93.3%和148.4%; 无性系21-3的根系氮、磷吸收效率受氮影响较小; 根系氮、磷利用效率均无显著变化。上述结果表明, ≤1.5 mm的细根的增生发育和氮、磷吸收效率的提高可能是磷高效马尾松无性系应对高氮低磷环境的重要响应机制。     

不同遮光处理对平茬后厚朴萌蘖株部分形态及生理指标的影响

以自然光照(遮光率0.0%)为对照,对遮光率20.0%、52.5%和78.6%条件下平茬后厚朴(Magnolia officinalis Rehd.et Wils)萌蘖株的部分形态和生理指标进行比较.结果表明:随遮光率提高,3个遮光处理组萌蘖株的株高呈现逐渐增大的趋势,萌蘖株叶中的叶绿素a、叶绿素b、类胡萝卜素和总叶绿素含量也基本上呈现逐渐增大的趋势,但萌蘖株的地径却呈现逐渐减小的趋势.萌蘖株的冠幅,单桩的萌蘖株数、叶片总数和叶芽总数,叶长和叶宽,单叶的干质量和叶面积,叶中叶绿素a含量与叶绿素b含量的比值(Chla/Chlb)和可溶性糖含量均在遮光率52.5%条件下最大,但仅冠幅、单桩叶片总数、单叶面积和叶中可溶性糖含量显著大于对照,分别较对照增加156.21%、28.18%、129.02%和64.31%;并且,多数指标在遮光率20.0%条件下居中、在遮光率78.6%条件下最小.然而,萌蘖株的叶长宽比、比叶质量及叶的相对含水量和可溶性蛋白质含量则在遮光率52.5%条件下最小,但仅比叶质量显著小于对照,较对照减少37.43%;并且,多数指标在遮光率20.0%条件下居中、在遮光率78.6%条件下最大.研究结果显示:适当的遮光处理能够促进平茬后厚朴萌蘖株的生长,遮光率52.5%为最优的遮光处理条件.     

基于芽苗砧嫁接油茶砧穗创伤后内源激素动态变化分析

为研究油茶(Camellia oleifera A)嫁接时穗条和砧木创伤后内源激素动态变化规律,解析影响砧穗嫁接面愈合的生理机制,为油茶砧穗愈合生长机理提供理论支持。以树龄6年的长林18号和53号的穗条和实生砧木为材料,按照芽苗砧嫁接方法切割穗条S0(0 min)、S10(10 min)、S40(40 min)和砧木茎段Z0(0 min)、Z10(10 min)后,利用液质联用法(HPLC-MS)测定吲哚乙酸(IAA)、脱落酸(ABA)、反式玉米素(TZR)、玉米素(Zeatin)、水杨酸(SA)和茉莉酸(JA)含量,分析不同时间段内源激素变化及品种间差异的关系。结果显示:创伤后18号的TZR、Zeatin和SA含量总体高于53号;18号IAA、SA和JA逐渐下降;TZR和Zeatin分别在S10和S0达最高值后下降;ABA在S10达最高值。53号IAA和JA爱S10达最高值后下降;TZR、Zeatin和SA在S10达低值后逐渐上升;ABA在S0达高值后逐渐下降。砧木茎段创伤前后激素含量除JA外18号高于53号;两品种Z0时激素含量下降,Z10后上升,仅53号ABA和SA含量在Z0达高值后下降。砧木茎段和根部激素含量在品种间除JA外18号高于53号,茎段的IAA、ABA高于根部,其他激素为根部高于茎段。激素比值在品种间和部位间差异明显;IAA/ABA、IAA/TZR、IAA/Zeatin和IAA/JA、ABA/TZR、ABA/Zeatin和ABA/JA比值为53号高于18号;穗条内SA/IAA为18号高于53号,SA/JA和SA/ABA为53号高于18号;砧木茎段均为18号高于53号;TZR/SA、TZR/JA比值在穗条和砧木茎段为18号高于53号。两品种创伤后IAA与JA极显著正相关,而IAA与SA,SA与JA在18号极显著正相关,53号极显著或显著负相关;53号TZR、Zeatin、SA间极显著或显著正相关,JA与TZR、Zeatin和SA极显著负相关。砧木茎段创伤后18号激素间为极显著或显著正相关;53号TZR和Zeatin与IAA、JA极显著正相关,与SA存在显著负相关,SA与JA有显著负相关。砧木茎段和根部间品种间仅在SA与各激素间相关性存在差异,其他激素间存在极显著正相关或负相关。综上所述,砧穗创伤后激素水平上18号在创伤面易于愈伤组织发育,而53号抗逆激素水平较高且与细胞分裂增殖类激素负相关,可能影响53号嫁接后愈合生长;嫁接应在创伤后10 min内较为适宜;砧穗间激素含量及比值的差异可能会影响后期嫁接部位形态重建以及穗条生长。