斑苦竹无性系种群克隆生长格局动态的研究

采用“例逐龄级累加法”（ＲＡＡ）研究了缙云山斑苦竹无性系种群的克隆生长格局动态,以及无性系分株克隆生长型的动态趋势．结果表明,作为复轴型的斑苦竹,其无性系种群随时间进程表现为聚集程度逐渐降低的集群分布格局．在自然条件下,斑苦竹更多地表现出单轴型的繁殖趋势．应用ＲＡＡ分析植物种群,尤其是竹类植物种群前期的克隆生长格局的动态,结果可靠,具有重要的应用价值．     

斑苦竹无性系种群克隆繁殖的动态与调节研究

本文依据了JLHarper (1977)的构件生物(madular organism)种群理论,将某一特定生境内的斑苦竹竹子的集合作为一个无性系种群,研究了它的克隆繁殖构件的数量动态,以及克隆繁殖与无性系基株年龄和分株密度的关系。结果表明:斑苦竹以Ⅲ龄级基株形成的克隆繁殖构件(笋芽)数量最多,以后,随龄级的增大而逐渐减少。发笋数、退笋数和成竹数均与无性系分株密度相关,它们的最适密度都为2.5×10株/ha。退笋率和成竹率与繁殖构件的出土时间呈直线相关关系。退笋率模型:D=27.253+0.702t(R²=0.636)成竹率模型:M=72.662-0.701t(R²=0.634)     

斑苦竹(Pleioblastus maculata)无性系种群的数量和年龄结构动态

依据Ｈａｒｐｅｒ（１９７７）提出的构件生物种群理论,将源于同一地下根茎的每一竹子个构件。把斑苦竹竹子构件无性系种各的生活史小循环划分为８个阶段,用Ｌｅｓｌｉｅ矩阵表 预测了四川晋云山该种群的数量和年龄结构变化趋势。结果表明,用Ｌｅｓｌｉｅ矩阵来预测靠无性繁殖来扩大种群数量的竹类植物的年龄结构和数量动态,具有较高的可靠性。     

杨树无性系PV曲线水分参数的研究

采用PV技术对8个杨树无性系(3、6、7、8、9、10、11、12号)的水分参数ψstlp、ψssat、RWCtlp、ROWCtlp、AWC、ξmax和b值等进行了研究,并采用抗旱性指数(DI)和模糊数学反隶属函数两种方法对各个无性系的抗旱性进行了综合评价.结果显示:8个无性系的ψstlp、ψssat、ROWCtlp、ξmax、b值不同,抗旱性也存在一定的差异.其中,11、7和8号维持膨压和渗透调节的能力比其余无性系强;11号具有很强的保持最大膨压和维持低水势的能力;7~9号无性系具有较强的忍耐水分胁迫和抗脱水的能力;3和6号细胞弹性最大,主要依靠其坚硬厚实的细胞保持体内的水分.结果表明,8个无性系分为3个类群:第一类群为无性系7、8、9、11、12号,抗旱性最强;第二类群为无性系10号,抗旱性居中;第三类群为无性系3号和6号,抗旱性最弱.     

白杨无性系秋季水分参数与冬季抗寒性指标关系研究

选用7个白杨杂种无性系1年生苗为材料,采用P-V技术于秋季落叶前测定各无性系枝叶水分参数Ψ0π、Ψ1π00、RWC0、ROWC0、mεax,并于冬季不同时期测定了各无性系相对电导率、钾离子渗漏率、SOD酶活性和POD酶活性的动态变化,对无性系抗寒性进行了综合评定。无性系各项生理指标存在一定变化模式,相对电导率、钾离子渗漏率在12月份降至最低,以后逐步提高,无性系间在2月份变异最大;SOD酶活性和POD酶活性在各时期无性系间差异均较大;无性系抗寒能力评价结果表明,从落叶开始,抗寒能力逐渐提高,12月至翌年1月达到最大,2月份又迅速下降,此时无性系间抗寒能力差异也达到最大。将水分参数与抗寒性指标进行相关分析表明,大部分水分参数与冬季不同时期的抗寒性指标存在不同程度的相关性,特别是与春季指标相关更加显著,其中Ψ0π是相关性最为显著的指标,Ψ1π00相关不明显。     

不同生境对苦竹鞭根形态结构及其异速生长的影响

鞭根作为竹子吸收养分和水分的主要器官,其形态结构性状与鞭根对养分斑块的敏感性及养分获取能力紧密相关。该研究选取相邻连续的苦竹(Pleioblastus amarus)纯林和苦竹-杉木(Cunninghamia lanceolata)混交林2种林分类型,将其分为苦竹林中心区、苦竹林界面区、混交林界面区和混交林中心区4种生境,测定4种林区生境的苦竹鞭根形态结构性状指标及生物量,比较其间的连续性变化规律,以明确竹子异质性环境下的生态适应策略。结果表明:(1)不同生境下,纯林界面区的苦竹拥有更高的鞭根节点数、根尖数以及更小的根直径;纯林界面区和混交林界面区的苦竹鞭根比根长、比根面积均显著高于纯林中心区,但两个界面区的苦竹鞭根根直径则表现相反。(2)从苦竹纯林中心区至混交林中心区方向,苦竹鞭根生物量呈逐渐降低的趋势,但苦竹林界面区和混交林界面区间差异不显著。(3)生境对苦竹主要鞭根形态结构性状异速增长速率无明显影响,但显著提高了苦竹林界面区鞭根主要形态结构性状的差异性位移量;不同生境下苦竹鞭根形态结构存在显著差异,苦竹纯林界面区的鞭根形态结构可塑性较强,拥有更高的鞭根活性以及更活跃的生理功能。研究发现,生境对苦竹主要鞭根形态结构性状有显著影响,但对其异速增长速率无明显影响;鞭根直径是苦竹获取资源的重要影响因子,异质生境下苦竹趋向于采取增加鞭根面积和降低鞭根直径的策略以最大化地获取资源。     

羊草种群无性系生长格局的研究

 本文根据野外实测数据和采用数学分析方法,在研究羊草种群无性系营养扩散和生长过程的基础上,建立了符合描述羊草种群无性系生长格局的相关随机走动模型和简单扩散模型。对模型进行检验,结果表明,所建模型可以定量地描述羊草种群无性系的生长格局。     

樟子松无性系生长性状与结实量变异研究

为选育高产、优质的樟子松种质资源,本研究以吉林省白城市林木种子园的304个樟子松无性系为材料,对其生长性状（树高、地径、胸径、3 m处直径、冠幅、分枝角度和侧枝粗度）和结实性状（2015、2016和2017年的结实量）进行调查分析。方差分析结果表明除冠幅外无性系间各性状差异均达极显著水平（P<0.01）;各指标表型变异系数的变化范围为3.79%~65.22%,重复力变化范围为0.24~0.70;相关性分析结果表明除侧枝粗度与3 m处直径相关未达到显著水平外,树高、胸径、地径、冠幅与侧枝粗度间相关均达极显著水平,不同树龄的结实量与大部分生长性状相关未达显著水平。依据生长性状,以5%的入选率对无性系进行综合评价,15个无性系入选,入选无性系在树高、地径、胸径、3 m处直径、分枝角度和侧枝粗度等指标的遗传增益分别为5.47%、4.48%、15.18%、11.78%、2.38%和6.66%;依据3年结实量,以5%的入选率对无性系进行综合评价,15个无性系入选,入选无性系在2015年、2016年和2017年的平均结实量的遗传增益分别为2.89%、46.32%和13.88%。该研究为樟子松种子园优良无性系的选择提供材料,也为吉林西部樟子松良种选育提供基础。     

新疆伊犁河谷平原狗牙根无性系构件的生长

采用随机挖掘整个无性系的方法,在新疆伊犁河谷平原2年无人工管理的葡萄园撂荒地,对狗牙根无性系进行了大样本取样,定量分析了构件生长的规律.结果表明：在30个狗牙根无性系中,分株数平均为（272.6±186.6）个,其中营养分株占总分株数的82.3%,是生殖分株的4.3倍;无性系总生物量为(45.4±40.0) g,其中根茎占总生物量的54.4%,营养分株占21.0%,匍匐茎占14.8%,生殖分株占9.4%;根茎与匍匐茎的累计长度分别为(5.1±4.7) m和(3.3±3.4) m、着生的芽数分别为(291.5±246.8)和(78.8±87.4)个.根茎和匍匐茎芽数与无性系的营养分株、生殖分株、根茎和匍匐茎的数量性状之间均呈极显著的正相关关系(P<0.01),表明在新疆伊犁河谷平原,狗牙根无性系主要以根茎芽实现其持续更新.     

Effects of moisture availability on clonal growth in bamboo Pleioblastus maculata

The effects of moisture availability on clonal growth and biomass investment in the bamboo Pleioblastus maculata were investigated over a four-year period by transplanting Pleioblastus maculata clones into soils with different levels of moisture availability in the field. The results showed that: (1) The higher the moisture availability, the greater the total biomass of P. maculata clones. Although fewer culms are produced at the higher moisture levels, mean tiller biomass is greater. (2) Under different levels of moisture availability, obvious differences in the total rhizome length (p < 0.01), spacer length (p < 0.05) and the sizes of bamboo culms (height, p < 0.01; diameter, p < 0.01) were observed. Thus, the higher the moisture availability, the shorter the rhizomes and the larger ramets. (3) In microhabitats with low moisture availability, bamboo allocated more biomass to underground organs, which promotes elongation of rhizomes and increases root production, thereby helping to capture underground resources essential to growth. In microhabitats of high moisture availability, the biomass is primarily allocated to the aboveground growth of ramets. (4) We suggest that soil moisture availability effects the foraging strategies of bamboo, that bamboo plants growing with low moisture availability produce longer rhizomes (that is, more, although shorter, spacers) with more biomass allocation than plants in high moisture and have a better ability to forage to increase the probability of locating adequate moisture patches. Also, longer length distance between shoots (that is, longer spacers) in high soil moisture than in low is adapted to avoid intense competition from faster growing aboveground growth in high moisture patches.     

Differential effects of water depth and sediment type on clonal growth of the submersed macrophyte <Emphasis Type="Italic">Vallisneria natans</Emphasis>

The response of clonal growth and ramet morphology to water depth (from 60 to 260 cm) and sediment type (sand versus organic clay) was investigated for the stoloniferous submersed macrophyte Vallisneria natans in an outdoor pond experiment. Results showed that water depth significantly affected clonal growth of V. natans in terms of clone weight, number of ramets, number of generations, clonal radius and stolon length. V. natans showed an optimal clonal growth at water depths of 110–160 cm, but at greater depths clonal growth was severely retarded. A high allometric effect was exhibited in ramet morphology. Along the sequentially produced ramet generations, ramet weight and plant height decreased while stolon length and the root:leaf weight ratio increased. When using ramet generations as covariate, sediment type rather than water depth more strongly affected the ramet characteristics. For plants grown in clay, ramet weight, ramet height and stolon length were greater, and plants exhibited lower root:leaf weight ratio. These data suggest that water depth and sediment type have differential effects on clonal growth of V. natans: Water depth appears primarily to affect numerical increase in ramets and spatial spread, whereas sediment type mainly affects biomass accumulation and biomass allocation. Handling editor: S. M. Thomaz     

Honeybee males use highly concentrated nectar as fuel for mating flights

Honeybees use nectar held in the crop as their main source of energy for flight but the mass of the crop nectar load may be a cost burden. This study investigated whether males of the honeybee Apis mellifera adjust their nectar fuel load and concentration to enhance the success of mating flights. When the crop content was compared between males staying in the hive and those departing, the latter group had the larger volume (median, 5.0 μl; range, 0.0–17.8 μl) and higher concentration (median, 71.6%; range, 49.0%–77.6%), indicating that departing males load concentrated nectar as fuel before mating flights. Moreover, the crop nectar concentration was significantly higher in departing males than in departing workers. These results suggest that concentrated nectar is advantageous to males because it provides more sugar for energy at lower mass and secures longer or more effective mating flights for higher chance of reproductive success. No significant effect of age was detected in crop volume, and concentration and amount of dissolved sugars in the crop content. In addition, laboratory experiments showed that males had only about 5 μl of nectar in the crop soon after feeding, irrespective of fed volume (5–15 μl), suggesting they do not hold much nectar in the crop but send it rapidly to the midgut, unlike workers.     

试论东北地区农业节水与农业水资源可持续利用

针对振兴东北老工业基地大背景下的东北地区水资源紧缺状况,通过对农业水资源和农业节水潜力的系统分析,提出了东北地区的系统农业节水战略．根据东北地区农业生产特点和农业发展需求,进行节水农业分区,确定不同农业类型区节水高效栽培模式与关键集成技术体系．论述了东北地区农业水资源可持续利用系统学方略和实施系统节水治水工程的必要性,以及农业节水研究的发展趋势．     

松嫩草地两种趋异型羊草克隆构型特征比较

This paper studied the clonal architecture of two divergent Leyrnus chinensis types (grey-green type and yellowgreen type) in Songnen grassland, and compared their internode length, spacer length, interbranching length, interbranching angle, and ramet population density and height under the same habitat. The results showed that there was no significant difference in these clonal characteristics except spacer length and ramet population density between the two types of L. chinensis, and yellow-green type, with less spacer length and more ramet density than grey-green type, should be more adaptable to the resourceful habitat. Moreover, the V-indices of the clonal architecture of two divergent L. chinensis types were all close to 1, and the difference was not significant. Therefore, both of the two types belonged to typical guerilla clonal plant.