Effect of carbon dioxide, fertilization and irrigation on loblolly pine branch morphology

 Foliage and wood parameters of branches of 12-year-old loblolly pine (Pinus taeda L.) trees were characterized after 21 months of exposure to fertilizer, irrigation and elevated CO₂ treatments. Branches of loblolly pine trees were enclosed in plastic chambers and exposed to ambient, ambient +175 and ambient +350 umol mol^–1 CO₂ concentrations. Measurements of foliage and wood at the fascicle, flush and branch levels were made at the end of the 21 month study period. The +350 CO₂ treatment did not significantly increase fascicle radius or length but did increase the number of fascicles on the first flush. Fertilization significantly increased fascicle radius and length, while irrigation significantly increased number of fascicles and flush length of first flush. The +350 CO₂ treatment also significantly increased flush length of the first flush. Significant interaction of fertilization and irrigation with CO₂ was observed for fascicle length. Significant interactions of fertilization and irrigation were also observed for flush length, number of fascicles and fascicle length. Observed increases in fascicle radius, fascicle length, number of fascicles and flush length may have been responsible for the significantly higher flush leaf area observed for the all three treatments. Also, a combination of fertilization and irrigation increased leaf area by 82% compared to that in the control when averaged across CO₂ treatments. At the branch level +350 CO₂ treatment significantly increased shoot length but not the number of flushes on the branch. In general with the exception of bark density and total number of needle scales, neither fertilization nor irrigation had any significant effect on other branch level parameters. Results from this study indicate that with ‘global change’ an increase in CO₂ alone may increase leaf area via an increase in flush length and number of fascicles. Combining increases in CO₂ with fertilization and irrigation could greatly enhance leaf area which when coupled to observed increases in net photosynthesis as a result of elevated CO₂ could greatly increase productivity of loblolly pine trees. Received: 22 August 1996 / Accepted: 5 March 1997     

不同林龄胡杨活立木枯枝生物量和化学计量特征

基于不同林龄胡杨天然林样地活立木枯枝(DBST)生物量调查,探讨不同发育阶段胡杨活立木枯枝化学计量和碳储量的时空变化规律。研究结果表明:(1)不同林龄胡杨林活立木枯枝生物量随着林龄增加呈先增加后减小趋势,其中成熟林活立木枯枝生物量最大(10.93 t/hm~2),占地上生物量的17.79%。对于单株胡杨而言,随林龄增加活立木枯枝生物量增大,年平均活立木枯枝生物量为0.22 kg/株。同时胡杨枝径级越大越易形成枯枝,生物量也随枯枝径级的增加而增加。(2)胡杨活立木枯枝C、N、P、K平均含量分别为491.01、4.13、2.75、1.83 g/kg,活立木枯枝C、N、P元素含量高于活体枝,而活体枝K元素含量高于活立木枯枝。胡杨群落活立木枯枝平均C∶N、C∶P、N∶P比分别为:128.58、232.79、1.95,其活立木枯枝化学计量比均高于活体枝。林龄对化学元素含量和化学计量比影响均差异不显著(P0.05),说明了胡杨活立木枯枝的元素含量随龄级变化不大,具有稳定的特点。(3)活立木枯枝碳密度随林龄的增加先增加后降低,其中成熟林碳密度最大;胡杨群落平均碳密度为2.63 t/hm~2,占地上活立木碳密度的20.74%。研究认为胡杨群落枯枝生物量和碳密度随林龄增加的变化规律明显,胡杨活立木枯枝在荒漠森林生态系统中是不可忽略的C库。     

留营养枝对棉株同化物生产,运转,分配及产量的影响

运用＾１４Ｃ示踪技术研究了留营养支棉株＾１４Ｃ同化物生产运转分配规律。结果表明：留营养枝与否对全株＾１４Ｃ总同化量基本没有影响,但留营养２枝棉株果枝叶的相对光合强度（以放射性比强度表示）降低;主茎叶、果枝叶的＾１４Ｃ同化量显著降低;营养２叶具有较高的光合作用强度和向外输送＾１４Ｃ同化物的转运速率,在＾１４Ｃ同化物生产运转分配中占有很重要的地位。留营养枝棉株＾１４Ｃ同化物的转运速率,在＾１４Ｃ同化     

国产柽柳科3属6种植物营养枝的解剖观察

对国产柽柳科3属6种植物(琵琶柴、沙生柽柳、山川柽柳、多枝柽柳、刚毛柽柳、疏花水柏枝)营养枝解剖结构的比较研究表明：其当年生营养枝在表皮是否具毛、皮层细胞的形态结构、维管束排列方式、形成层的发生、髓部面积及内含物等性状上存在差异,并根据这些差异列出了分属检索表。所选6种植物生态型各不相同,其中琵琶柴为地带性超旱生小半灌木,柽柳为非地带性的潜水性旱、中生灌木,疏花水柏枝为湿、中生灌木。通过比较这6种植物的解剖结构,发现随着生境由湿生向旱生变化,营养枝解剖结构也发生了相应的变化,并与生境形成了良好的适应。     

松树内含物与松墨天牛种群数量的关系

对不同林分松墨天牛种群密度进行解剖调查,黑松为32.63头/株,马尾松为16.69头/株,湿地松为12.44头/株,黑松与湿地松之间差异显著;对黑松、马尾松、湿地松枝条及韧皮部中蛋白质、可溶性糖、水分、N、P、K、S、Cl、Ca、Mg、Cu、Zn、Fe、Mn、16种游离氨基酸和16种水解氨基酸进行测定,并与黑松、马尾松、湿地松上的松墨天牛种群数量(y)之间关系进行数学分析。蛋白质(x1)、可溶性糖(x2)与y的关系为y=-44.07-1.5601x1+6.9355x2,复相关系数为0.8374*;游离氨基酸与y的关系为y=63.24-1.1775x5-0.0680x11+0.1665x12-0.1257x15,复相关系数为0.9999**。x5为甘氨酸、x11为酪氨酸、x12为苯丙氨酸、x15为脯氨酸;水解氨基酸与y的关系为y=37.59-0.1146x10-0.5741x11+0.0112x15+0.1468x16,复相关系数R为0.9955**,x11为酪氨酸、x15为脯氨酸、x16为精氨酸、x10为亮氨酸;矿质元素与y的关系为y=-67.94+409.4696x3+37.4746x6-1004.4480x7+4.2958x8,复相关系数R为0.9826*,x3为K、x6为Ca、x7为Mg、x8为Cu。综合分析14种入选的内含物与y的关系为y=19.94+0.0114x2+0.0457x4-0.5317x5+62.5214x9,复相关系数R为0.9966**,x2为水解酪氨酸、x4为水解脯氨酸、x5为游离酪氨酸、x9为K,综合分析表明水解和游离的酪氨酸、水解脯氨酸和K的含量对松墨天牛种群有重要影响。     

林木非同化器官树枝（干）光合功能研究进展

尽管多数林木非同化器官树干、树枝内都存在绿色组织（Chlorenchyma）,但是其生态学意义很少为人注意。综合前人研究结果,得出以下结论：（1）树枝的光合速率（暗呼吸与饱和光照下呼吸之差）的在0～10μmolm^-2s^-1之间,而大部分的结果认为光合速率在0．5～3．Oμmolm^-2s^-1之间。而且多数研究认为其是对自身呼吸的再固定,而不是对外界大气CO2的吸收,对再固定率（光合／呼吸比值）分析表明80％以上的研究结果认为树干光合作用能够固定40％～100％呼吸所释放的CO2。但其对个体乃至林分整体碳平衡的影响报道的较少。（2）不仅非同化器官光合作用直接影响其呼吸作用,冠层叶片光合产物对非同化器官的气体代谢也产生显著影响,但新形成光合产物和储藏碳水化合物是否存在功能上的差异不同学者意见不一。（3）尽管叶绿素含量多在80～450mgm^-2之间,低于相应叶片叶绿素含量340～620mgm^-2,但其叶绿素a／b平均值（2．5）显著低于叶片的平均值（3．6）（P〈0．0001）,说明更加适应于阴生环境。（4）有关类胡萝卜素在非同化器官的功能,比较传统的观点认为其单位质量或者单位面积含量远低于叶片,是一种适应于低光照环境的表现,但最近研究表明其单位叶绿素含量远高于叶片,可能是在高浓度CO2条件下、叶绿体片层结构酸性化导致光合过程中光化学淬灭能力低下,需要以叶黄素循环为主导能量淬灭过程保证其功能正常。（5）在树皮光学特性方面,大部分光照被吸收,而有少部分被反射和透射。在透光率方面,70％左右的结果认为树皮的透光率在5％～15％之间,而超过85％的结果认为透光率在0％～20％之间。而且光照可以在木质化树干导管、纤维及管胞有效进行轴向导光,树干内部的光以红外和远红外光为主,其它低波长光的透射能力远低于红外光。（6）尽管已有研究表明某些草本植物茎具有C4特征,但对于多数、特别是木本植物未见报道,特别是对于茎内高浓度CO2、高红／蓝光比、低氧特征对光合机构的影响尚需要深入研究。     

果树枝条栽培灵芝的品质特性分析

【目的】研究果树枝条作为栽培基质对赤灵芝(菌株:金地灵芝)子实体品质的影响。【方法】比较果树(苹果、桃树、梨树)枝条和常规杂木屑栽培灵芝的农艺性状、营养成分及活性成分含量的变化,进一步对其改善睡眠的功能进行评价。【结果】果树枝条栽培的灵芝品质具有较大的差异。3种果树枝条栽培的灵芝菌丝体生长速度显著低于常规组(P0.05),发菌时间延长7-13 d,同时产量有不同程度的下降。各组间的营养成分含量无明显差异,而果树枝条组的矿质元素含量均显著大于常规组。此外,虽然果树枝条组的灵芝多糖含量较常规组低,但是均能够有效延长小鼠注射戊巴比妥钠后的睡眠时间,并且梨树枝条组能够有效缩短睡眠潜伏期,增加小鼠的入睡率(P0.05),改善睡眠功能显著。【结论】利用果树枝条栽培灵芝对其产量和农艺性状指标有一定影响,但是具有较好的改善睡眠的功能。因此,通过果树枝条配方优化,栽培高品质灵芝是切实可行的。     

中国长蠕孢属的分类研究Ⅱ.四川省的两个新种

报道生于四川省枯树枝上的长蠕孢属两个新种,假喙长蠕孢Helminthosporium spurirostrum和四川长蠕孢Helminthosporium sichuanense。假喙长蠕孢的分生孢子可产生假喙,这是首次报道长蠕孢属的一个新的特征。四川长蠕孢与黄檀长蠕孢H.dalbergiae较相似,但是黄檀长蠕孢的分生孢子大(长58-125μm,宽12-14μm),分生孢子梗细(宽10-12μm)。研究标本保存在山东农业大学植物病理学标本室(HSAUP)。     

Gene tree quality affects empirical coalescent branch length estimation

Assessing effects of gene tree error in coalescent analyses have widely ignored coalescent branch lengths (CBLs) despite their potential utility in estimating ancestral population demographics and detecting species tree anomaly zones. However, the ability of coalescent methods to obtain accurate estimates remains largely unexplored. Errors in gene trees should lead to underestimates of the true CBL, and for a given set of comparisons, longer CBLs should be more accurate. Here, we furthered our empirical understanding of how error in gene tree quality (i.e., locus informativeness and gene tree resolution) affect CBLs using four datasets comprised of ultraconserved elements (UCE) or exons for clades that exhibit wide ranges of branch lengths. For each dataset, we compared the impact of locus informativeness (assessed using number of parsimony-informative sites) and gene tree resolution on CBL estimates. Our results, in general, showed that CBLs were drastically shorter when estimates included low informative loci. Gene tree resolution also had an impact on UCE datasets, with polytomous gene trees producing longer branches than randomly resolved gene trees. However, resolution did not appear to affect CBL estimates from the more informative exon datasets. Thus, as expected, gene tree quality affects CBL estimates, though this can generally be minimized by using moderate filtering to select more informative loci and/or by allowing polytomies in gene trees. These approaches, as well as additional contributions to improve CBL estimation, should lead to CBLs that are useful for addressing evolutionary and biological questions.     

黔金丝猴昼间休息团抱模式

2008年12月至2009年4月在梵净山国家级自然保护区东北部岩高坪片区对黔金丝猴（Rhinopithecus brelichi）昼间休息行为进行了研究。采用随机取样法（ad libitum sampling）,观察记录黔金丝猴个体的休息姿势、休息位置的林层高度、休息时利用支撑物树枝的粗细与倾斜角度以及团抱组合的个体数量等休息行为相关参数。研究发现黔金丝猴昼间休息行为主要选择利用林层的树冠中位,占总频次的52%;黔金丝猴的休息姿势主要为坐姿,占总频次的99%,偏好利用直径介于5 ~ 10 cm之间中等粗细树枝作为支撑物;选择支撑物树枝的倾斜角度趋近于水平;昼间休息多采用2只个体组成的团抱模式;猴群休息位置支撑物树枝直径与树冠层高度呈显著负相关;黔金丝猴在树冠各层间休息时的平均团抱大小差异显著。树冠层支撑物资源在树冠的垂直分布可能是黔金丝猴昼间休息行为利用树冠层高度与团抱模式的主要影响因子。