重庆市四面山不同土地利用类型饱和导水率

[目的]探讨不同土地利用类型和土壤理化性质对饱对导水率的影响。[方法]采用定水头法测定四面山不同土地利用类型的饱和导水率,并运用回归分析,相关分析和主成分分析法分析其与土壤物理因子和有机质的关系,以及影响饱和导水率的主导因子。[结果]各土地利用类型的平均饱和导水率均高于荒地,其顺序为:林地农地草地,林地中天然林饱和导水率大于人工林;饱和导水率随土层深度的增加呈负指数递减规律;饱和导水率与容重呈幂函数关系,与孔隙度呈正相关,与黏粒含量呈负相关;有机质含量的提高对饱和导水率有积极的促进作用。[结论]影响饱和导水率的主导因子是容重、有机质、非毛管孔隙度和毛管孔隙度,其次,土壤机械组成对其也有一定影响。     

乌兰布和荒漠生态系统12种沙生灌木苗期的抗旱性

[目的]建立沙生灌木抗旱性评价指标体系,为沙区优良树种的筛选提供科学依据。[方法]以乌兰布和荒漠生态系统12种沙生灌木的2年生幼苗为材料,测定了7项水分生理指标,采用主成分分析和聚类分析对灌木抗旱性进行了研究。[结果](1)麻黄(Ephedra distachyaLinn.)、白刺(Nitraia tangutorum Bobr)及柠条锦鸡儿(Caragana korshinskii Kom.)的水势低于其他9种灌木;霸王(Zygophyllum xanthoxylon Maxim.)的束缚水含量和束缚水与自由水(Va/Vs)比值较高,分别为64.20%,3.3;沙木蓼(Atraphaxis bracteata A.Los.)、白刺及柽柳(Tamarix chinensis Lour.)的蒸腾速率显著低于其他9种灌木;梭梭(Haloxylon ammodendron(C.A.Mey.)Bunge)与麻黄的恒重时间最长,均为144h;沙冬青(Ammopiptanthus mongolicus(Maxim.ex Kom.)Cheng F.)的残留含水率最高(44.80%)。(2)水势、Va/Vs值、残留含水率、束缚水、恒重时间、蒸腾速率6个指标对植物抗旱性的影响较大,累积方差贡献率达87.59%。[结论]依照抗旱性大小将12种植物分为三类,强抗旱灌木为麻黄;中抗旱灌木为梭梭、白刺、霸王;弱抗旱灌木为花棒(Hedysannn scoparium Fisch)、杨柴(Hedysarum mongolicum Turcz.)、柽柳、柠条锦鸡儿、沙冬青、沙木蓼、沙拐枣(Calligonum mongolicum Turcz.)、小叶锦鸡儿(Caragana microphylla Lam.)。     

Observations on interspecific compatibility and meiotic chromosome behavior of Capsicum buforum and C. lanceolatum

The wild species, Capsicum buforum Hunz. and C. lanceolatum(Greenm. ex J.D. Sm.) Morton and Standl. were hybridized to nine different Capsicum species to understand their taxonomic and genetic relationships. With C. buforum as the male parent, the compatibility to the nine species varied from species to species and ranged from producing under-developed embryo, seed coat, seedless fruit, to no fruit set. When C. buforum was the female parent, it was incompatible (no fruit set) to the nine Capsicum species tested. When C. lanceolatum was the female parent, the hybridizations to the other species ranged from aborted embryo, seed coat, seedless fruit or no fruit. As a pollen parent, C. lanceolatum was incompatible (no fruit set) to the species investigated. In pollen mother cells (PMCs) of C. buforum, 24 chromosomes (n = 12) paired as 12 bivalents with chromosome lagging at meiotic anaphase-I. Twenty-six chromosomes (n = 13) were detected in PMCs of C. lanceolatum. In C. lanceolatum most chromosomes paired as bivalents, but one quadrivalent was observed in some cells. C. buforum was found to be self-incompatible, while C. lanceolatum was self-compatible.     

Polymorphism of high molecular weight glutenin subunits in three species of Aegilops

A collection of 136 accessions of Aegilops umbellulata (39), Ae. comosa (75) and Ae. markgrafii (22) was analysed for high-molecular-weight (HMW) glutenin subunits composition. The homogeneity of the accessions was studied and 55.1% of the collection was homogeneous for HMW glutenin subunits (29 Ae. umbellulata, 33 Ae. comosa and 14 Ae. markgrafii). The HMW glutenin subunits of Ae. umbellulata are encoded by the Glu-U1 locus; in Ae. comosa results showed that this proteins are encoded at the 1M chromosome, and the locus was named Glu-M1. In Ae. markgrafii it was assumed that HMW glutenin subunits were encoded by an homoeologous locus and it was named Glu-C1. All the accessions of Ae. umbellulata and Ae. markgrafii expressed both, x-type and y-type subunits. Among the Ae. comosa accessions, only one expressed an x-type subunit alone. All the accessions of Ae. umbellulata and some of Ae. comosa had x-type glutenins of higher molecular weights than those commonly present in bread wheat. A total of 8 alleles were detected at the Glu-U1 locus, 11 at the Glu-M1 and 4 at the Glu-C1. The new HMW glutenin variation found in this work suggests their possible utilisation in breeding for wheat quality.     

两种退耕还林模式对土壤微生物优势类群的影响

以两种退耕还林模式的桦木林地、苦竹林地和农耕地(对照)为对象,对各样地土壤微生物优势类群数量的季节性动态变化、垂直分布特征及其与土壤酶活性的相关性进行了研究。结果表明,土壤微生物的优势类群为微球菌属(Micrococcus)、芽孢杆菌属(Bacillus)、链霉菌属(Streptomyces)、游动放线菌属(Actinoplanes)、酵母菌(未定属)、木霉菌属(Trichoderma)这6类。两种退耕还林模式下土壤优势微生物类群数量存在差异,春、夏、秋三季均为苦竹林所占比例最大,冬季为桦木林最大。两种林地和农耕地土壤微生物优势类群数量季节性变化规律为微球菌和酵母菌在夏、冬季较大,春、秋季较少;芽孢杆菌在秋季最大,夏季最小;游动放线菌与木霉菌数量在四季中变化不大;链霉菌是夏季最高,冬季最少。各优势微生物类群数量的垂直分布特征表现为微球菌、游动放线菌、木霉菌随土壤层的加深其数量逐渐降低,芽孢杆菌、链霉菌数量则随土壤层的加深而逐渐增加,酵母菌随土壤层的加深其数量减少,但趋势不明显。两种林地对各优势微生物类群数量的根际效应为:链霉菌和木霉菌的R/S值大于1,酵母菌的R/S值小于1,微球菌和游动放线菌在桦木林的R/S值大于1而在苦竹林小于1。在优势微生物类群和土壤酶之间,微球菌与转化酶,芽孢杆菌与纤维素酶,木霉和游动放线菌与过氧化氢酶,酵母与脲酶呈显著正相关关系。     

Cytological and genetic mapping of the gene for four-awned phenotype in <Emphasis Type="Italic">Triticum carthlicum</Emphasis> Nevski

A striking feature of Triticum carthlicum Nevski (2n = 4x = 28, AABB genome) is an awn-like appendage on the glume, so all the spikelets appear four-awned. From the word “tetraaristatus” (four-awned), the locus was named “t” to distinguish it from the b ₁ locus on chromosome 5A and b2 locus on chromosome 6B for awn formation. The aims of present study was to determine the chromosomal location of the t locus in tetraploid wheat T. carthlicum, and (2) to assess linkage relationships of t, Rht12 using microsatellite markers in T. carthlicum. Combined cytological evidence and microsatellite mapping showed that t was located on the chromosome 5AL. The alignment of the gene was Xgwm291–(6.4 cM)–t–(6.7 cM)–Xgwm410 in F₂ of T. carthlicum #521/LD222, and Xhbg219–(12.4 cM)–t–(5.1 cM)–Xgwm410–(6.2 cM) –Rht12 in F₂ of ANW 16C/#521 on the 5AL. The t locus was different from b1 locus, because it was known that the semi-dwarf Rht12 gene was completely linked with b1 gene. We discussed that the four-awned phenotype of T. carthlicum was introduced from Triticum aestivum L. ssp. carthlicoides.     

Genetic mapping of the gene for brittle rachis in a <Emphasis Type="Italic">Triticum aestivum</Emphasis>—<Emphasis Type="Italic">Aegilops triuncialis</Emphasis> introgression line

Aegilops triuncialis L. (2n = 4x = 28, genome formula UUCC) has been used to obtain one of the “Arsenal collection”, the distant hybridization of Triticum aestivum L. The introgression line 124/00ⁱ, which was derived from the cross of T. aestivum ‘Rodina' with γ-irradiated pollen of an accession of Ae. triuncialis. However, undesirable genes can be incorporated into the cultivated varieties from Ae. triuncialis. The spikes of Ae. triuncialis disarticulate from stems at a single node at the bottom of the spikes. It was defined as a synaptospermic diaspore. However, the spike of 124/00ⁱ unexpectedly disarticulate below each spikelet showing wedge type of disarticulation. The brittle rachis gene Br ¹²⁴ (B rittle r achis of 124 /00 ⁱ ) of 124/00ⁱ was allelic to Br2 located on the short arm of chromosome 3A. From the microsatellite mapping, the Br ¹²⁴ gene was bracketed by Xbarc19 (20.3 cM) and Xgwm779.1(14.3 cM) on the short arm of chromosome 3A. The present study suggested that the dominant mutation from synaptospermic diaspore to wedge type disarticulation occurred in the gamete of Ae. triuncialis when Ae. triuncialis pollen was treated with γ-irradiation.     

太行山典型区域不同林分类型枯落物水文效应

采用样地调查和室内浸泡法,对河北易县洪崖山自然保护区葫芦峪林场6种不同林分类型枯落物的水文效应进行研究。结果表明:6种林分类型枯落物的蓄积量范围为5.25～15.70 t/hm~2,蓄积量总体为阔叶林刺槐最大,针阔混交林次之,针叶林最小,各林分半分解层蓄积量总体大于未分解层(油松纯林、黑枣和油松混交林未分解层大于半分解层);最大持水量范围为10.55～25.04 t/hm~2,阔叶林栓皮栎(25.04 t/hm~2)最大,刺槐纯林(23.66 t/hm~2)次之,针叶林油松(10.55 t/hm~2)最小;最大持水率范围是171.19%～260.20%,针叶林油松最大,侧柏最小;有效拦蓄量范围为6.25～17.60 t/hm~2,阔叶林栓皮栎(17.60 t/hm~2)最大,刺槐纯林次之(17.30 t/hm~2),针叶林侧柏(6.25 t/hm~2)最小;有效拦蓄率略有不同,针叶林油松最大,其值为180.29%,阔叶林栓皮栎(162.98%)次之,针阔混交林黑枣和油松最小,其值为77.22%。综合研究分析表明,栓皮栎和刺槐的枯落物层持水能力较佳,该地区栓皮栎林和刺槐林枯落物层水源涵养能力优于其他4种林分类型的枯落物。     

不同灌溉条件下不同类型冬小麦产量水分利用效率差异原因分析

以旱地品种"西峰20"和"晋麦47"、水旱兼用型品种"石家庄8 号"、高水肥地品种"石4185"和"科农9204"5 个冬小麦品种为材料, 通过田间不同灌溉处理试验研究了不同抗旱类型冬小麦品种收获指数和群体水分利用效率对产量水分利用效率的影响差异。结果表明: 不同抗旱类型的小麦在不同灌溉处理下, 产量水分利用效率(WUE_y)以及变化趋势存在显著差异。旱地冬小麦品种WUE_y 和收获指数(HI)显著低于水地品种和水旱兼用型品种。不同品种间WUE_y 最大相差42.01%, HI 相差25.91%。HI 和群体水分利用效率(WUE_bm)与WUE_y 呈显著正相关关系。株高与HI 呈显著负相关关系(R²=0.574)。在不灌溉条件下, 品种间WUE_y 差异源自HI 的差异; 而在补充灌溉条件下, 品种间WUE_y 的差异源自WUE_bm 和HI 的共同作用。说明不同抗旱类型的小麦对不同灌溉处理的响应方式和适应策略不同。旱地品种在干旱胁迫条件下, 主要靠增加WUE_bm 来提高WUE_y; 而水地品种和水旱兼用型品种在补充灌溉中凭借较高的WUE_bm 和HI 共同作用提高WUE_y。     

光辐射强度对侧柏油松幼苗光合特性与水分利用效率的影响

 探讨不同土壤水分条件下光辐射强度对侧柏和油松苗木光合特性与水分利用效率的影响规律,可为林木栽培和管理提供科学依据。在黄土半干旱区,采用人工控制土壤水分的方法,利用模拟光源研究了侧柏和油松苗木的净光合速率、蒸腾速率、水分利用效率和胞间CO2浓度随模拟光辐射增强的变化规律。结果表明:在模拟光辐射为0～2200μmol/（m2.s）的范围内,侧柏和油松叶片的净光合速率、蒸腾速率和水分利用效率均随光辐射强度的增强而增大,但光辐射强度进一步增强,侧柏和油松净光合速率和水分利用效率呈下降趋势;在同样土壤水分条件下,侧柏净光合速率、蒸腾速率和水分利用效率高于油松,侧柏光饱和点高于油松,而侧柏光补偿点低于油松,侧柏光能利用率高于油松;随着土壤水分的增加,侧柏与油松净光合速率、蒸腾速率和胞间CO2浓度升高,而水分利用效率降低。在土壤含水量为7.90%、13.00%和19.99%条件下,侧柏光饱和点分别为1275、1 450和1 675μmol/（m2.s）,光补偿点分别为4225和13μmol/（m2.s）,由光饱和点对应最大净光合速率分别为3.04、4.06和5.53μmol/（m2.s）;在土壤含水量为7.83%1、3.04%与20.15%条件下,油松光饱和点分别为11001、325和1500μmol/（m2.s）,光补偿点分别为60.30和23μmol/（m2.s）,由光饱和点对应最大净光合速率分别为1.08、3.35和4.36μmol/（m2.s）。     

晋西黄土区典型林分枯落物层水文生态特性研究

选择山杨栎类次生林（以下简称次生林）、刺槐林、侧柏林、油松林为研究对象，通过样地调查，结合室内浸泡方法，对比分析枯落物（未分解层、半分解层）的水文特征指标，研究典型林分枯落物层水文生态特性。结果表明：（1）枯落物厚度为3.93~4.95 cm，刺槐林最大，油松林最小；蓄积量为次生林最大（19.28 t/hm²），侧柏林（18.03 t/hm²）和刺槐林（17.57 t/hm²）次之，油松林最小（14.73 t/hm²），未分解层蓄积量小于半分解层。（2）枯落物最大持水量（率）为30.92~61.31 t/hm²（197%~320%），次生林最大，依次为刺槐林、侧柏林，最小为油松林。（3）枯落物有效拦蓄存在显著差异（P>0.05），表现为次生林（31.29 t/hm²） > 刺槐（22.20 t/hm²） > 侧柏（18.19 t/hm²） > 油松（13.94 t/hm²），有效拦蓄率为107%~173%。（4）在浸水2 h内，枯落物持水量和吸水速率变化以次生林与刺槐林最为迅速，半分解层较未分解层变化迅速；持水过程中，两者与时间分别呈对数函数（R²>0.89）和幂函数关系（R²>0.99）。在4种林地中，次生林林下枯落物水文生态潜力最优，油松纯林最差，表现为次生林 > 刺槐 > 侧柏 > 油松。刺槐是除次生林外的3种人工林中最优林种。建议研究区内合理优化恢复树种配置，以提高水文生态功能。     

农业景观格局对玉米害虫-捕食性天敌定性食物网结构的影响

农业过度集约化带来的农业景观均质化已成为农田生物多样性降低的主要原因之一。为研究农业景观格局对害虫-捕食性天敌定性食物网结构的影响,本文选择辽宁省昌图县为研究区,选取8个典型田块为样区,在分析定性食物网结构的基础上,采用回归分析和最优模型确定食物网参数与景观指数之间的关系。结果表明:1)互作丰度(IR)与各景观指数无显著相关性。2)连接密度(LD)与蔓延度指数(CONTAG, x1)、聚集度指数(AI, x2)呈显著正相关(P0.05),最优模型为:LD=-64.621+0.780x1+0.739x2。农业景观中非耕作斑块越聚集,玉米害虫-捕食性天敌定性食物网结构越复杂。3)连接性(C)与CONTAG(x1)、香农多样性指数(SHDI, x3)呈显著正相关(P0.05),而与香农均匀度指数(SHEI,x4)呈显著负相关(P0.05),最优模型为:C=-178.500+1.831x1-106.808x4。景观类型越多样,且同类斑块连接度越好,害虫与捕食性天敌的相互作用越频繁,也越有利于复杂食物网结构的维持。4)普遍性(G)与景观形状指数(LSI, x5)、斑块结合指数(COHESION, X7)、AI(x2)呈显著正相关(P0.05),而与斑块密度(PD,x6)呈显著负相关(P0.05),最优模型为:G=-2 994.798+26.891x2+27.090x5-0.491x6+2.851x7。非耕作斑块破碎化程度越低,天敌的搜寻行为和聚集行为越强,越有利于食物网结构的稳定。5)易损性(V)与SHEI(x4)呈显著正相关,而与CONTAG(x1)呈显著负相关(P0.05),最优模型为:V=8.411+5.351x4。斑块类型在景观中分布越均匀,害虫多样性越高,群落结构也越复杂。总体而言,农业景观异质性越强越有利于玉米害虫-捕食性天敌定性食物网的构建和抗干扰性的增强。而利用田间数据构建食物网矩阵的方法可以成为研究如何增强农业景观异质性的有力工具。     

贺兰山10种典型植物固碳释氧能力研究

为探讨贺兰山典型植物固碳释氧能力,运用Li-6400XT便携式光合仪对贺兰山10种乔灌草进行了光合生理指标的测定,计算10种乔灌草不同尺度的日固碳释氧量,并分析其固碳释氧能力.结果表明:(1)青海云杉的单株叶面积、单株叶干重、叶面积指数显著高于其他植物;苔草的比叶面积最高,且呈现出草本>灌木>乔木的规律;披针叶黄华的日...     

Contributions of root respiration to total soil respiration before and after frost in Populus euphratica forests

Temporal changes in soil CO₂‐efflux rate was measured by a canopy‐gap method in a Populus euphratica forest located at the both sides of Tarim River banks (W China). Soil CO₂‐efflux rates in situ were correlated with key soil biotic (e.g., fungal, bacterial, and actinomycetes populations) and abiotic (e.g., soil moisture, temperature, pH, organic C) variables. Two kinds of measurement plots were selected: one under the crown of a living Populus euphratica tree and the other under a dead standing Populus euphratica tree. Diurnal variations in soil respiration in these plots were measured both before and after the occurrence of the first frost. Soil respiration of the dead standing Populus euphratica (Rd) was assumed to be a measure of heterotrophic respiration rate (Rh), and root respiration rate (Rr) was estimated as the difference between soil respiration under living (Rl) minus soil respiration under dead standing Populus euphratica. Daily variation of Rr contribution to the total soil respiration in Populus euphratica forests were analyzed before and after the frost. The contribution of root respiration to total soil respiration before and after frost varied from 22% to 45% (mean 30%) and from 38% to 50% (mean 45%), respectively. In addition, Rh was significantly correlated with soil temperature both before and after frost. In contrast, Rr was not significantly correlated with soil temperature. Change in Q₁₀ of Rr was different from that of Rh from before the frost to after the frost. Variation of Q₁₀ of Rr from before the frost to after the frost was larger than that of Q₁₀ of Rh. Thus, the results indicate that different soil respiration models are needed for Rr and Rh because different factors control the two components of soil respiration.     

大豆幼苗光合特性对锰营养的响应

采用溶液培养方法,设Mn2+浓度为0、0.05、0.50、5、30、50.mg/L,探讨了2种大豆品种(浙春2号、东北大豆854-11)的幼苗光合特性对不同锰浓度的响应。结果表明,低锰浓度提高了大豆叶片的初始荧光(Fo)、最大荧光(Fm)、PSⅡ原初光能转化效率(Fv/Fm)、潜在光化学活性(Fv/Fo)和光化学猝灭系数(qP),高锰降低了Fo、Fm、Fv/Fm、Fv/Fo、qP。随着锰营养的增加,非光化学猝灭系数(qN)增大。适量的锰浓度显著提高了大豆的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs),降低了气孔阻力(Rs)和细胞间CO2浓度(Ci),随着锰浓度的逐渐增大,降低了Pn、Tr、Gs,提高了Rs、Ci。0.50.mg/L下的锰浓度有最大的Fo,5.mg/L下的锰浓度有最大的Fm、qP、Fv/Fm、Fv/Fo,表明0.505～mg/L的锰浓度有利于大豆的光合作用。在50.mg/L的锰浓度下,两个大豆品种有最大的qN、Rs、Ci和最小的Tr、Pn,此时两个品种大豆耗散了过剩的激发能,降低了大豆叶片的光合速率,对大豆已产生了一定的伤害。两个品种大豆光合特性对锰的响应存在着基因型差异,浙春2号较东北大豆耐锰胁迫。     

The origin of the A genome donor of wheats (Triticum: Poaceae) – a perspective based on the sequence variation of the 5S DNA gene units

In a prior study on the haplomes of wheat using the 5S rRNA gene we assigned the long A1 and short A1 unit classes to the A haplome in the diploid T. monococcum. The short A1 unit class is absent in the tetraploids T. turgidum and T. timopheevii and in the hexaploid T. aestivum, although present in the hexaploid T. zhukovskyi. Both T. turgidum and T. aestivum contained a different 5S DNA unit class labeled the short A2.The purpose of this paper was to study the short A2 units in the two diploid species to shed light on the theory that the A haplome donor of T. turgidum and T. aestivum was T. urartu. Fifty eight clones were obtained from 12 accessions, sequenced and analyzed. As expected T. baeoticum, which is often classified as a subspecies of T. monococcum, contained the long A1 and the short A1 5S DNA units. Unexpectedly, T. urartu had the long A1 and the short G1 unit classes instead and other units not found so far in Triticum. These findings support the hypothesis that the donor of the A genome in T. zhukovskyi was T. monococcum, as identified by the short A1 units. However, the short A1 units are absent in T. timopheevii, also a carrier of the A genome. The short G1 units found in T. urartu also identify it as a possible donor of the G genome to T. timopheevii. The short G1 units were also found in T. aestivum in our prior study. The long G1 unit class was not found in T. urartu but reported from T. timopheevii and T. zhukovskyi. The implications of these and related findings on the evolution of wheats are discussed.     

遗传算法率定参照作物腾发量相关参数的研究

用气象资料计算参照作物腾发量(ET0)的方法需要各种气象(候)和物理参数,净辐射是其中的重要数据之一,而专业测量净辐射的设备在农业气象站里很少安装。为解决计算ET0时缺少太阳净辐射(Rn)测量值这一实际问题,该文采用浑善达克沙地东南缘南沙梁草甸草原区气象站观测的气象资料,用遗传算法模型对联合国粮农组织56号文本(FAO56)推荐值(as和bs)进行率定,计算了对应夏半年(4—9月)和冬半年(1—3月和10—12月)的太阳净辐射和参照作物腾发量,并将率定前后的模拟太阳辐射进行对比分析,用残差估计指数法对该方法模拟的参照作物腾发量模拟精度进行了分析。结果表明:在缺少太阳净辐射测量值的地区,采用FAO56参数(as和bs)推荐值与遗传算法模型率定参数(as和bs)相比,净辐射年内变化趋势一致,采用率定后参数计算的净辐射相对更不稳定,波动更大,但能有效提高参照作物腾发量计算精度。误差较大的模拟值均出现在降雨日前后,降雨虽然并未直接出现在Penman-Monteith公式中,但是降雨必然会对湿度和温度等气象条件造成一定影响,而as和bs是受湿度等因素影响而变化的,其深层次的原因有待进一步分析。