Seasonal Changes in the Milt Quality of Waigieu Seaperch,Psammoperca waigiensis: Implications for Artificial Propagation

Milt quality of Waigieu seaperch was sampled at the beginning, the middle, and the end of the spawning season to assess if the sampling season has an effect on milt quality parameters. The milt volume and total sperm production were higher at the middle of the spawning season while the sperm concentration in milt was significantly higher at the beginning and the end of the spawning season. Sperm morphology and the major parameters of seminal plasma (pH, total protein, Mg²⁺, or Ca²⁺ concentrations) did not differ throughout the spawning season. The concentrations of Na⁺ and the osmolality increased throughout the spawning season. The percentage of motile cells did not differ during the spawning season while the duration of sperm motility (swimming duration) and velocity (swimming speed) were significantly different during the spawning season. The fertilization rate (75.7 ± 6.8%) and hatching rate (56.5 ± 3.1%) at the middle of the spawning season were higher than at the beginning and end periods. Results indicated that milt quality parameters and fertility success in the middle of the spawning season were higher compared to earlier and later sampling dates. Thus, we recommend collecting milt during this time for maximal fertilization and hatching success.     

黑龙江省国有林区脆弱异质性家庭对停伐政策的态度及影响因素研究

基于2016年黑龙江省重点国有林区348户家庭的微观调查数据,实证分析黑龙江省国有林区脆弱异质性家庭对停伐政策的态度及影响因素。采用因子分析与综合评价法将348户职工家庭分为脆弱性家庭和非脆弱性家庭,描述性分析2组样本家庭对停伐政策的态度及认知情况,利用多元有序logit模型分析脆弱性与非脆弱性家庭对停伐政策态度的影响因素。结果表明:非脆弱性家庭对停伐政策的了解程度及执行情况的评价均高于脆弱性家庭,脆弱性家庭相对非脆弱性家庭对停伐政策的认可度较高,但是应对风险冲击的能力相对较低。脆弱性家庭和非脆弱性家庭对停伐政策的态度受户主特征、家庭特征以及政策认知特征变量的显著影响,但脆弱性家庭变量参数估计绝对值相对更大,因而停伐政策对脆弱性家庭有着更为敏感和强烈的冲击。     

Reproductive biology of the female Japanese mantis shrimp Oratosquilla oratoria (Stomatopoda) in relation to changes in the seasonal pattern of larval occurrence in Tokyo Bay, Japan

ABSTRACT:   The reproductive traits and the monthly larval abundance of the mantis shrimp Oratosquilla oratoria were investigated in Tokyo Bay, Japan, in 2002. The goal of the study was to elucidate the cause of changes in the monthly pattern of larval abundance from the 1980s to the 1990s as these changes relate to variation in the stock size of the adult shrimp. Oogenesis was divided into 10 stages by histological observation. The developmental stage of oocytes in an individual's ovary was synchronous, suggesting that almost all the oocytes in an ovary are spawned at the same time. The size at first maturity was estimated to be 7 ≤ body length ( BL ) < 8 cm. Fecundity was expressed as a function of BL , ranging from 19 300 eggs for 8 cm BL to 92 100 eggs for 14 cm BL . Small female shrimps (<10 cm BL ) spawned around August. Most large female shrimps (≥10 cm BL ) spawned around May, and some large female shrimps also spawned until September. Although most large female shrimps spawned in spring, the larval abundance was low before July and high from August onwards. The results suggest that a substantial decrease in the stock size of large individuals causes the low larval abundance before July.     

小麦矮秆育种中性状间关系的多元分析

以7个株高梯度系列的35个系统及5个亲本品种为材料,采用典范分析和逐步回归分析研究了株高及其构成因子与产量因子、产量生理性状间的关系。结果表明:①株高因子通过产量生理性状影响产量因子,一定的生物学产量是获得高产的基础。②矮秆品种的高化对提高产量、千粒重和收获指数有利,对蛋白质含量的影响不明显;高秆品种矮化能显著提高收获指数,对籽粒的蛋白质含量影响不大。③在主要性状符合育种目标的前提下,选择倒二节间较长、第一和第二叶间距略长、穗颈和穗部较长的类型可能对提高产量有利。     

‘过山香’香蕉多芽体的诱导及其体细胞胚的发生

 以我国重要香蕉种质‘过山香’ (AAB) 为材料, 研究了香蕉多芽体诱导、多芽体茎尖薄切片即分生组织性的表层结构物( scalp) 愈伤组织诱导和体细胞胚发生的合适条件。结果表明, 该品种单个不定芽茎尖在P4培养基(含BAP 100 μmol·L ^{- 1}和IAA 1 μmol·L ^{- 1} ) 中继代5个周期后可诱导获得类似花椰菜结构的多芽体。从30 μmol· m ^{- 2} ·s^{- 1}光强, 光/暗周期(16 h /8 h) 培养的多芽体所获得的scalp在添加2,4-D 5μmol·L ^{- 1}和Zeatin 1 μmol·L ^{- 1}的愈伤组织诱导培养基中黑暗培养, 45 d后愈伤组织诱导率可达97.6%。诱导20 d后黄色分生小球体类结节状愈伤组织开始发生, 90～120 d后在分生小球体局部可获得白色或浅黄色松散的胚性愈伤组织(诱导率为17.5% ) 。从胚性愈伤组织诱导的体细胞胚在成熟培养基上培养60 d后体胚萌发率和植株转化率分别为14.5%和11.1%。     

Enhancing pedotransfer functions with environmental data for estimating bulk density and effective cation exchange capacity in a data‐sparse situation

Soil bulk density (BD) and effective cation exchange capacity (ECEC) are among the most important soil properties required for crop growth and environmental management. This study aimed to explore the combination of soil and environmental data in developing pedotransfer functions (PTFs) for BD and ECEC. Multiple linear regression (MLR) and random forest model (RFM) were employed in developing PTFs using three different data sets: soil data (PTF‐1), environmental data (PTF‐2) and the combination of soil and environmental data (PTF‐3). In developing the PTFs, three depth increments were also considered: all depth, topsoil (<0.40 m) and subsoil (>0.40 m). Results showed that PTF‐3 (R²; 0.29–0.69) outperformed both PTF‐1 (R²; 0.11–0.18) and PTF‐2 (R²; 0.22–0.59) in BD estimation. However, for ECEC estimation, PTF‐3 (R²; 0.61–0.86) performed comparably as PTF‐1 (R²; 0.58–0.76) with both PTFs out‐performing PTF‐2 (R²; 0.30–0.71). Also, grouping of data into different soil depth increments improves the estimation of BD with PTFs (especially PTF‐2 and PTF‐3) performing better at subsoils than topsoils. Generally, the most important predictors of BD are sand, silt, elevation, rainfall, temperature for estimation at topsoil while EVI, elevation, temperature and clay are the most important BD predictors in the subsoil. Also, clay, sand, pH, rainfall and SOC are the most important predictors of ECEC in the topsoil while pH, sand, clay, temperature and rainfall are the most important predictors of ECEC in the subsoil. Findings are important for overcoming the challenges of building national soil databases for large‐scale modelling in most data‐sparse countries, especially in the sub‐Saharan Africa (SSA).     

基于环境变量的中国土壤有机碳空间分布特征

研究中国土壤有机碳(Soil Organic Carbon,SOC)的空间分布特征对SOC储量估算以及农业生产管理具有重要意义。以全国第二次土壤普查2473个土壤典型剖面的表层(A层)SOC含量为研究对象,探寻地形、气候和植被等环境因素对SOC空间异质性分布的影响;以普通克里格法为对照,利用地理加权回归、地理加权回归克里格、多元线性回归和回归克里格模型建立SOC空间预测模型;并分别绘制了中国SOC的空间分布预测图。结果表明:(1)SOC含量与年均降水量、年均温、归一化植被指数、高程以及地形粗糙指数呈极显著相关关系;(2)平均绝对估计误差、均方根误差、平均相对误差和皮尔逊相关系数等模型验证指标表明地理加权回归的预测精度优于其他模型,可以更好地绘制SOC在大尺度上的空间分布特征;(3)较高SOC含量主要分布在研究区东北部、西南部以及东南部,而西北部SOC含量普遍偏低。本文以期从大尺度上探讨土壤属性与环境变量之间的相关关系,为全国土壤属性的空间制图提供一定的解决方案和思路。     

番茄绿果与橙果间果实颜色及主要色素含量的遗传研究

对番茄组合绿樱(绿果)×金珠1号(橙果)的6个世代遗传群体(P1、P2、F1、BC1、BC2和F2)进行果色性状、番茄红素含量、叶绿素含量和胡萝卜素含量等的遗传规律分析。结果表明:正反交F1的果色性状无明显差异,而色素含量存在显著差异;说明番茄果色性状受核基因控制,而色素含量遗传除受核基因控制外还可能存在胞质效应。采用多世代联合分析法的分析结果表明,番茄绿果与橙果间的果色性状符合2对加性主基因+加性-显性多基因(MX2-A-AD)遗传模型,其BC1、BC2和F2主基因遗传率分别为73.42%、78.25%和61.41%,多基因遗传率分别为22.87%、15.35%和34.94%,即果色性状遗传的主基因遗传力较强;叶绿素含量符合1对负向显性主基因+加性-显性多基因(MX1-AEND-AD)遗传模型,其BC1、BC2和F2主基因遗传率分别为0、1.73%和0.65%,多基因遗传率分别为45.47%、0和37.82%,即主基因遗传力在BC2群体中最高,多基因遗传力在BC1群体中最高;番茄红素含量与胡萝卜素含量均符合2对加性-显性-上位性主基因+加性-显性多基因(MX2-ADI-AD)遗传模型,其BC1、BC2和F2主基因遗传率分别为75.74%、1.79%、84.26%和61.53%、87.21%、81.05%,多基因遗传率分别为20.32%、74.12%、12.68%和0.68%、0、0,表明番茄红素含量和胡萝卜素含量的主基因遗传力较强。