Upscaling as ecological information transfer: a simple framework with application to Arctic ecosystem carbon exchange

Transferring ecological information across scale often involves spatial aggregation, which alters information content and may bias estimates if the scaling process is nonlinear. Here, a potential solution, the preservation of the information content of fine-scale measurements, is highlighted using modeled net ecosystem exchange (NEE) of an Arctic tundra landscape as an example. The variance of aggregated normalized difference vegetation index (NDVI), measured from an airborne platform, decreased linearly with log(scale), resulting in a linear relationship between log(scale) and the scale-wise modeled NEE estimate. Preserving three units of information, the mean, variance and skewness of fine-scale NDVI observations, resulted in upscaled NEE estimates that deviated less than 4% from the fine-scale estimate. Preserving only the mean and variance resulted in nearly 23% NEE bias, and preserving only the mean resulted in larger error and a change in sign from CO₂ sink to source. Compressing NDVI maps by 70–75% using wavelet thresholding with the Haar and Coiflet basis functions resulted in 13% NEE bias across the study domain. Applying unique scale-dependent transfer functions between NDVI and leaf area index (LAI) decreased, but did not remove, bias in modeled flux in a smaller expanse using handheld NDVI observations. Quantifying the parameters of statistical distributions to preserve ecological information reduces bias when upscaling and makes possible spatial data assimilation to further reduce errors in estimates of ecological processes across scale.     

Rapid seedlings regeneration from seeds and vegetative propagation with sucker and rhizome of Eremospatha macrocarpa (Mann & Wendl.) Wendl and Laccosperma secundiflorum (P. Beauv.) Kuntze

To develop efficient seedling production methods for Laccosperma secundiflorum and Eremospatha macrocarpa, a study was conducted to examine regeneration using offsets combined with several physical and chemical treatments of seeds. Offsets categorized into small, medium and large diameters, were planted in three conditions: shaded and open nursery, and greenhouse. We tested sucker from E. macrocarpa, and sucker and rhizome from L. secundiflorum. For both species, high viability percentage (ranging from 55% to 100%) were observed for small and medium suckers planted in shaded nursery and greenhouse, against less than 49% for sucker planted in open nursery. The mean seedling emergence times were estimated to 84, 77 and 75 days after planting (DAP) for small, medium and large sucker of L. secundiflorum, respectively under open nursery condition, and 76, 75, 95 DAP for small, medium and large suckers of the same species, respectively in shaded condition. Greenhouse has a significant positive effect on E. macrocarpa seedlings emergence time. For this species, the mean seedling emergence times were estimated to 43 DAP for small sucker and 76, 93 DAP for medium and large suckers. No seedling was obtained from rhizome planted in all the growing conditions tested. Concerning seed dormancy breaking, germination percentages and rates were determined for 13 treatments. The best treatments were pre-soaking unscarified seeds for 4 days in 1.01 g l⁻¹ and 0.10 g l⁻¹ KNO₃, with 79% and 68% of germination, respectively and in 3.46 × 10⁻³ g l⁻¹ GA₃ for 68% of germination. These methods are suggested to improve germination of L. secundiflorum seeds. Successful and recommended methods for E. macrocarpa are pre-soaking scarified seeds in 3.46 × 10⁻³ g l⁻¹ and 3.46 × 10⁻⁴ g l⁻¹ GA₃, 96% and 94% of germination, respectively. Dormancy, probably a combination of mechanical and chemical dormancy, is present in the two species.     

黄瓜游离小孢子培养诱导成胚和植株再生

 以10个不同基因型黄瓜为试材进行游离小孢子培养,通过对成胚条件的系统研究,从‘7447’和‘Poinsett97’中获得了子叶形胚和再生植株。研究结果表明：基因型和小孢子发育时期是限制黄瓜游离小孢子成胚的关键因子。不同品种间胚状体产量差异显著,每皿产胚1.5～33.4个。单核靠边期是进行黄瓜游离小孢子培养的最佳时期。低温预处理有利于胚状体的诱导,4 ℃预处理2～4 d为宜,以处理2 d时胚状体产量最高。外源激素在诱导胚状体时并非必需,但低浓度的外源激素（0.5 mg·L^-1 2,4－D、0.2 mg·L^-1 6－BA）更能促进小孢子成胚。NLN和B5两种基础培养基在诱导胚状体上无显著差异。子叶形胚易分化成苗,而其它类型的胚状体不能获得再生植株。     

菊苣子叶离体培养与植株再生的研究

以菊苣无菌苗的子叶为外植体,研究其在附加不同浓度NAA和6-BA的培养基上的分化情况.结果表明:在不同培养基上,菊苣子叶均能诱导出淡黄色的愈伤组织和分化形成不定芽,但不同基因型菊苣的出愈率和不定芽诱导存在明显差别.诱导Rossa di Verona tardiva selez prelude和Rossa di treviso菊苣愈伤组织形成和芽分化的最佳培养基为MS+NAA 0.5 mg/L+6-BA 2 mg/L;而诱导In miscuglio菊苣愈伤组织和芽分化的最佳培养基为MS+NAA 0.5 mg/L+6-BA 3 mg/L.     

茄子的组织培养和植株再生体系研究

以2个茄子品种：红茄和紫长茄的子叶和下胚轴为外植体,探讨了不同生长调节物质对外植体分化的影响和不同品种、不同外植体的分化能力差异,并建立了茄子的高频率离体再生体系。结果表明：培养基MS＋2,4-D 1.0 mg/L＋6-BA 0.5 mg/L诱导愈伤组织效果最好;诱导不定芽方面,培养基MS＋4-PU 0.1 mg/L诱导效果最好;1/2MS培养基较MS培养基更适合植株生根。     

金光杏梅叶面积回归测算研究

以金光杏梅成熟叶片为试材,研究了叶长、叶宽与叶面积的关系.结果表明:叶长、叶宽与叶面积均呈正相关关系.叶长、叶宽与叶面积之间的相关系数分别为0.7084、0.8546,叶长和叶宽与叶面积的复相关系数为0.9868,在0.01水平下均达到了极显著水平.在此基础上建立了叶长(x1)、叶宽(x2)、叶长和叶宽与叶面积(y)之间的回归方程y=61.4140x1-2 480.6、y=28.7600x2-0.8546、y=17.6276x1+41.2594x2-1 078.4906,3个回归方程均可用于测算金光杏梅的叶面积,其中以叶长和叶宽与叶面积的二元回归方程测算结果更为精确.在具体应用中,可根据所要求的精确度进行选择.     

云南枇杷野生种质资源叶片性状多样性分析

对147份云南枇杷野生资源叶片表型性状进行了调查分析,结果表明,这一群体枇杷种质资源的叶姿、叶形、叶片长度、叶片宽度、叶形指数、叶背茸毛、叶面形态、叶片横切面形状、叶面光泽、叶片颜色等性状均存在丰富的多样性。其中,叶背无茸毛的种质占77.62%,初步断定这个群体中的多数种质不是普通枇杷类型。     

地膜覆盖栽培对春小麦叶片衰老特性的影响

为了揭示春小麦在地膜栽培条件下是否早衰的问题,采用管栽模拟试验的方法,研究了地膜覆盖和露地栽培条件下春小麦叶片的叶绿素、蛋白质、叶片丙二醛(M DA)含量和细胞质膜相对透性的变化。结果表明,采用地膜覆盖栽培方法,在春小麦生长前期能明显提高叶片叶绿素和蛋白质的含量(日均增加量分别比露地春小麦高31.49%和7.94%),但后期又会加速其降解速率;M DA含量和细胞质膜相对透性均表现为覆膜处理高于露地处理(日均增加量分别比露地春小麦高71.96%~11.78%和2.42%~9.57%)。说明覆膜栽培可使春小麦提前进入正常衰老阶段,但由于其增温、保湿等效应,使春小麦生长量增加,穗粒数和穗粒重比露地春小麦提高22.95%和27.68%,表现出良好的增产效应。     

钾肥不同施入量对水稻产量及钾肥利用率的影响

以超级稻“盐丰47”为材料,采用小区对比试验方法,探讨了钾肥不同施量对水稻生育性状、产量及钾肥利用率的影响。结果表明,施人钾肥（K20）4．5kg／667m。的处理K1．5获得单产613．6kg／667m2,比K2、K3、Kl、K4、K0处理分别增产了0．1％、0．8％、1．1％、2．6％、2．7％;其单位面积有效穗数、颖花数以及干物质产量、齐穗后干物质积累量占籽粒产量的百分比、钾肥利用率均较高。试验条件下的适宜施钾量（I（20）为3．0-4．5kg／667m2。     

不同灌水次数和施氮量对冬小麦群体动态和产量的影响

为了明确灌水次数和施氮量对高产冬小麦群体动态和产量的影响,分别于2006-2007、2007-2008年度在保定市和藁城市用当地冬小麦推广品种河农822和石新616研究了不同灌水次数(在保证底墒基础上全生育期灌0、1、2和3水,分别用W0、W1、W2和W3表示)和施氮量(0、112.5和225 kg/ha,分别用N0、N1和N2表示)对小麦群体动态和产量的影响.结果表明,2006-2007年度灌水次数和施氮量对小麦总茎(穗)数的影响较显著.W1、W2和W3的成穗数显著高于W0,W1、W2、W3之间差异不显著.3个施氮水平间各生育时期的总茎数均差异显著,且随施氮量增加而增大.大部分生育时期不同灌水次数的LAI差异不显著,而不同施氮量的LAI差异显著,N2的LAI显著高于N1和N0.灌水次数对穗数和千粒重影响显著,施氮量对穗数和穗粒数影响显著,以致灌水次数和施氮量对小麦产量的主效应均达到显著标准.4种灌水水平的产量以W3最高,W0最低;3个施氮量中N1产量最高,N0最低.灌水次数和施氮量对小麦产量和各产量构成因素的交互作用显著,W0和W1条件下产量随施氮量增加而提高,而W2和W3条件下N1产量最高,且与N0差异显著.2007-2008年度试验中,灌水次数和施氮量对各生育时期的总茎数、LAI和产量的影响均不显著.根据本研究结果可知,在河北平原地区常年降水(小麦全生育期100 mm左右)和中等肥力条件下全生育期灌溉3次,施氮量为N 112.5～225 kg/ha以及丰水降雨年份和较高肥力条件下全生育期灌溉1或2次,相应地施氮225或112.5 kg/ha,可以分别取得较理想的产量.