Low P (LP) levels in leaves can affect their photosynthetic N-use efficiency (PNUE), internal N allocation, and mesophyll conductance to CO2 (gm). The changes in leaf internal N allocation and gm in N-fixing trees and the consequent changes in PNUE under low soil P treatments are not well understood. In this study, we exposed seedlings of Dalbergia odorifera, Erythrophleum fordii (N-fixing trees), Castanopsis hystrix, and Betula alnoides (non-N-fixing trees) to three levels of soil P. The effects were not consistent among species, and LP had no specific effect on N-fixing species. Saturated net CO2 assimilation rate (Asat) values in D. odorifera and C. hystrix were remarkably lower under LP than under high P (HP) because Cc in D. odorifera and Vcmax and Jmax in C. hystrix were reduced. Narea values in D. odorifera and C. hystrix were also reduced under LP, and the degree of reduction of Narea was larger than that of Asat, which resulted in decreased PNUE in these species. PR and gm in D. odorifera and PR, PB, and gm in C. hystrix significantly decreased under LP and were internal factors affecting the variation in PNUE in these two trees. PCW was significantly and linearly related to PR only in C. hystrix, indicating that more N was invested in the cell walls to resist the damage caused by low soil P, at the expense of Rubisco N. Our results showed that soil P deficiency affected leaf N utilization, photosynthetic efficiency, and seedling growth.

以二年生平欧杂种榛幼苗为试材,采用盆栽控盐法,研究了不同浓度NaCl胁迫(0、50、100、200 mmol·L-1)对植株不同组织生物量和盐离子积累与分配特征的影响,以期明确平欧杂种榛对盐胁迫的响应与适应机制.结果表明:NaCl胁迫后,幼苗根、茎、叶、冠以及整株生物量积累显著下降,但根冠比显著提高.不同浓度NaCl胁迫下,植株生物量分配至根中最多(75.75％),其次为茎(8.34％),叶最少(15.91％).随着NaC1浓度的升高,不同组织Na+含量均呈大幅增加的趋势,其中,50、100 mmol·L-1和200 mmol·L-1 NaCl胁迫下根Na+含量较对照分别显著增加1.12、2.08倍和4.22倍.Na+含量表现为叶(18.46 mg·g-1)＞茎(2.58 mg·g-1)＞根(1.77 mg·g-1).随着 NaCl 浓度的升高,不同组织Na+净积累和相对净积累的变化趋势不尽相同.Na+净积累与相对净积累则表现为叶(70.99 mg·株-1 和 68.53％)＞根(28.03 mg·株-1 和 26.97％)＞茎(4.60 mg·株-1 和4.50％).综合分析表明,盐胁迫下平欧杂种榛通过将大比例生物量分配至根系的方式提高根冠比;同时,根系将吸收的过量Na+转运至叶片,使叶片最终成为Na的主要贮存库,一方面减弱Na+对根系的毒害,另一方面增强地上与地下部分之间的渗透势差,进而维持正常的生理功能.平欧杂种榛具有一定的耐盐性,可作为生态经济型树种在新疆盐碱地区合理开发利用.

为探讨栽植密度对枣园冠层结构特征及果实性状的影响,以新疆阿克苏温宿县10 a生骏枣园为研究对象,利用LAI-2200植物冠层分析仪测定4种栽植密度(A.0.5 m×4.0 m、B.1.0 m×4.0 m、C.1.5 m×4.0 m、D.2.0 m×4.0 m)枣园叶面积指数(LAI)、平均叶倾角(MTA)、冠层开度(DIFN)与相对光合有效辐射(PAR)的物候变化,分析果实性状.结果表明,随着物候推进,枣园LAI和DIFN均呈现出先增大后减小的趋势,与不同物候期叶幕体积大小有关.随着株距不断增大,枣园LAI减小,树冠DIFN增大,相对PAR增强,光能利用率提高.C的单果重、可溶性糖含量、单株产量及每公顷产量均高于A和B,可滴定酸含量则明显低于A和B,糖酸比显著高于其他3种栽植密度.综合以上结果可知,1.5 m×4 m栽植密度能有效改善枣园冠层结构特征与光能利用效率,在稳定枣果产量的前提下提升了枣果品质.

Soil greenhouse gas (GHG) fluxes relate to soil carbon and nitrogen budgets and have a significant impact on climate change. Nevertheless, the temporal variation and magnitude of the fluxes of all three major GHGs (CO2, CH4 and N2O) and their influencing factors have not been elucidated clearly in primary forests on the eastern Qinghai-Tibetan Plateau. Herein, field chamber GHG fluxes from May to November, soil microbial community and enzyme activity were analyzed in a fir-dominated (Abies fargesii var. faxoniana) primary forest. The emission rates of CO2 and N2O ranged between 64.69–243.22 mg CO2 m−2 h−1 and 1.69–5.46 ug N2O m−2 h−1, exhibiting a temporally unimodal pattern with a peak in July. The soil acted as a CH4 sink, and the uptake rate varied between 52.96 and 84.67 μg CH4 m−2 h−1 with the higher uptake rates in June and November. The temporal variation in the CO2 flux was significantly correlated with the geometric mean of enzyme activities, suggesting that the soil CO2 flux was determined by microbial activity rather than soil microbial biomass. The soil N2O flux was positively related to nitrate concentration with marginal significance, probably because N2O was a byproduct of nitrification and denitrification processes. The soil CH4 uptake was closely associated with methanotrophic biomass (18:1ω7c). The results highlight divergent temporal dynamics of GHG fluxes owing to different driving mechanisms and an important CH4 sink in the primary forest soil, helping to evaluate the carbon and nitrogen budgets of primary forests on the eastern Qinghai-Tibetan Plateau.

Floral zygomorphy (monosymmetry) is a key innovation in flowering plants and is related to the coevolution of plants and their animal pollinators. The molecular basis underlying floral zygomorphy has been analysed, and two regulatory pathways have been identified: one determines the dorsoventral (DV) asymmetry along the floral plan, and the other controls organ internal (IN) asymmetry during petal development. While strides have been made to understand the molecular mechanism controlling DV asymmetry, which mainly involves an interplay between TCP and MYB transcription factors, the molecular pathway regulating IN asymmetry remains largely unknown. In this review, we discuss what is known about regulators and the molecular pathway regulating IN asymmetry. Our analysis revealed that the regulation of IN asymmetry occurs at the cellular, tissue, and organ genesis levels during petal development and that the regulatory mechanism is likely integrated into different developmental paths, such as floral and root nodule development. Although the molecular regulation of IN asymmetry is not be a linear path, a key hub for the regulatory network could be vascular patterning during petal organogenesis.

研究盐胁迫下3个品种平欧杂种榛幼苗叶片解剖结构和离子代谢特征,以揭示盐胁迫响应与适应机制及不同品种的耐盐性差异.以'达维'、'辽榛7号'、'玉坠'2年生压条苗为材料,在盆栽条件下经轻度、中度、重度(分别为50、100、200 mmol/L NaCl)盐胁迫处理,设对照为0,研究幼苗叶片显微解剖结构参数和Na+、K+、Cl-、Ca2+含量的变化及其在根、茎、叶中的吸收、运输和分配特征.不同品种平欧杂种榛叶片厚度、上表皮厚度、下表皮厚度、栅栏组织和海绵组织厚度随着盐胁迫程度的增强呈现出先增加后降低的特点,轻度和中度胁迫下各参数显著高于对照.中度盐胁迫显著提高了各品种叶片结构紧密度.盐胁迫导致平欧杂种榛根、茎、叶Na+和Cl-含量明显高于对照.盐胁迫下,Na+和Cl-在叶中的绝对含量明显高于茎和根,但二者的增幅以根中最大,叶中最小,表明平欧杂种榛根系首先会吸收并截留一定数量的Na+和Cl-,然后将其运输至茎和叶中.与对照相比,轻度和中度盐胁迫下根、茎对K+和Ca2+的吸收保持稳定或减少,叶对K+和Ca2+的吸收则有所增加,重度胁迫下根、茎、叶K+含量以及茎、叶中Ca2+含量显著减少.盐胁迫导致不同品种平欧杂种榛根、茎、叶K+/Na+比和Ca2+/Na+比显著降低.随着盐胁迫程度的增强,不同品种平欧杂种榛从根到叶以及从茎到叶的SK+,Na+和SCa2+,Na+均表现为先升高后降低的趋势,盐胁迫对'辽榛7号'和'玉坠'从根到茎的SK+,Na+影响不显著.盐胁迫下,平欧杂种榛叶片通过一系列形态结构的调整来适应盐渍化生境,在积累盐离子的同时,通过加强对K+和Ca2+的选择性吸收和运输能力来维持体内的离子平衡以及较高的K+/Na+和Ca2+/Na+比,进而维持盐胁迫下机体正常的生理代谢活动.盐胁迫下'辽榛7号'表现出更强的形态与生理适应性,其耐盐性强于'达维'和'玉坠'.

[目的]在新疆伊犁对8年生达维平欧杂种榛的茎流速率进行一年的定点监测,同时观测了平欧杂种榛的果实不同发育期内气象和光合因子对茎流的影响,为榛树在干旱区的科学灌溉提供理论依据.[方法]利用包裹式茎流仪对盛果期的平欧杂种榛茎流速率进行连续测定,并监测样地的大气温度、太阳辐射、大气相对湿度和风速等气象因子并测定不同果实发育期的光合变化,研究气象、光合等因子对不同发育期榛树茎流变化的影响.[结果]整个果实生长发育期茎流速率昼夜变化差异较大,白天茎流速率变化曲线呈倒"U"形.茎流日累积量在不同发育期存在差异,果壳硬化期最大,为2.57L·d-1,坐果期最小,为1.65 L·d-1.太阳辐射、大气温度和叶片温度是果实生长发育期茎流速率的主要影响因子.对榛树不同果实发育期的茎流速率与气象因子、光合参数建立多元线性回归模型,经过回归系数和相关系数检验,多元线性回归方程均达到显著水平.[结论]在新疆伊犁地区,7月是榛果发育的果壳硬化期,榛树不仅自身生长旺盛,而且受太阳辐射、温度等因子的影响,导致果园蒸腾耗水量大,应及时补充灌水.

[目的]建立枣树花叶病毒病的分子检测方法,追踪检测与分析枣树花叶病毒病田间侵染动态,研究病害防治的关键时间节点,为新疆枣树种植区枣树花叶病毒病的流行监测和早期防治,以及枣树花叶病毒病的高效防治奠定基础.[方法]在前期准确获取病毒全基因组序列的基础上,以病毒基因组序列RNA5为靶标设计序列特异性引物,通过RT-PCR技术进行引物特异性验证与灵敏度检测,优化反应体系,建立枣树花叶病毒病分子检测技术,追踪检测与分析枣树花叶病毒病田间侵染动态.[结果]该检测技术对枣树花叶病毒病检测的最低浓度为4.79 pg/μL,可在叶片显症之前检测到该病毒.5月下旬至6月上旬是预防枣树病毒病的关键时间节点.[结论]建立的枣树花叶病毒病检测技术能够快速准确的检测和鉴定病原,可应用于枣树花叶病田间侵染动态的追踪检测.

研究了38个榛种质资源叶功能性状与光合特征参数的变异特征及其相关关系,为优良种质资源的选择以及进一步理解叶功能性状对光合特征的影响机制提供科学依据.结果表明:38个种质资源的叶面积(LA)、叶形指数(LI)、叶干重(LDW)、比叶面积(SLA)和叶干物质含量(LDMC)平均值分别为78.39 cm2、1.24、0.73 g,109.95 cm2·g-1和38.31％, LDW变异最大,其次为LA和SL4,LI和LDMC变异最小;净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(gs)、胞间CO2浓度(Ci)、气孔限制值(Ls)和水分利用效率(WUE)平均值分别为9.92 μmol ? m-2 ? s-1、3.88 mmol·m-2·s-1、153.04 μmol ? m-2 ? s-1、238.73 μmol ? mol-1、0.41和2.54 μmol·mmol-1,gs变异最大(27.89％),Pn、Ci、Ls和WUE 次之(10.37％～15.14％),Tr最小(9.99％).不同种质资源叶功能性状与光合特征参数之间均存在极显著差异.Pearson相关分析表明:Pn与LA、LDW、LDMC均呈显著正相关,与SLA则呈显著负相关;Tr与LA呈显著正相关;gs和Ci与LDMC分别呈显著负相关和正相关;WUE与LDW、 LDMC均呈显著正相关,与SLA则呈显著负相关.冗余分析表明:第1、2排序轴共同解释了叶片光合特征总变异的88.6％,其中,对光合特征产生显著影响的叶功能性状因子为SLA和LDMC.平欧210号、F-03、平欧11号、平欧88号、平欧119号、85-162、平欧48号、玉坠、平欧110号表现出较高的水分和光能利用效率.

Low light intensity can lead to a decrease in photosynthetic capacity. However, could N-fixing species with higher leaf N contents mitigate the effects of low light? Here, we exposed seedlings of Dalbergia odorifera and Erythrophleum fordii (N-fixing trees), and Castanopsis hystrix and Betula alnoides (non-N-fixing trees) to three irradiance treatments (100%, 40%, and 10% sunlight) to investigate the effects of low irradiance on leaf structure, leaf N allocation strategy, and photosynthetic physiological parameters in the seedlings. Low irradiance decreased the leaf mass per unit area, leaf N content per unit area (N-area), maximum carboxylation rate (V-cmax), maximum electron transport rate (J(max)), light compensation point, and light saturation point, and increased the N allocation proportion of light-harvesting components in all species. The studied tree seedlings changed their leaf structures, leaf N allocation strategy, and photosynthetic physiological parameters to adapt to low-light environments. N-fixing plants had a higher photosynthesis rate, N-area, V-cmax, and J(max) than non-N-fixing species under low irradiance and had a greater advantage in maintaining their photosynthetic rate under low-radiation conditions, such as under an understory canopy, in a forest gap, or when mixed with other species.

The dynamic effects of forest regeneration pattern after clear-cutting primary forest on soil N mineralization (Nmin) have not been well investigated and whether the effects vary with season is unclear in eastern Tibetan Plateau. In this study, we compared soil net Nmin, i.e. net ammonification rate (net Ra) and net nitrification rate (net Rn) among Picea asperata-broadleaf mixed forest (natural regeneration after planting P. asperata, MF), natural secondary forest (natural without assisted regeneration, NF) and P. asperata plantation (reforestation after clear-cutting primary forest, PF) from June to November, and measured soil microbial community and enzyme activities. Forest regeneration pattern significantly altered net Ra as well as net Nmin in June and November. Net Ra of MF, NF and PF in June was −0.29, −0.52 and 0.04 mg kg−1 d-1, respectively. NF was likely to have higher net NH4+ consumption in June presumably by the greater microbial utilization (biomass and enzymes) directly drove by the larger initial NH4+ concentration. NF had higher net NH4+ production (0.30 mg kg−1 d-1) in November than MF (0.15 mg kg−1 d-1) and PF (0.03 mg kg−1 d-1). Net Rn was insignificantly different among the regenerated forests and ranged between −0.13 and 0.39 mg kg−1 d-1 with a unimodal seasonal pattern. Nitrate dominated the inorganic N pool in PF while it was similar to ammonium in MF and NF in the middle of growing season, possibly suggesting an alteration of N preferences among the regenerated forests. Independent edaphic factors (including soil organic matter and available N) had greater explanations of net Ra variability (19.0%), while net Rn variability was more determined by enzyme activities (21.8%) and microbial community (13.1%). Overall, our results highlighted that the variations in soil net Nmin among three regenerated forests were dependent on season. Ammonium concentration before the start of growing season might play an important role in soil N dynamics. NF exhibited a larger N demand with regard to net Ra, microbial induces and N-acquisition enzymes. These provided essential information for understanding soil N dynamics and for developing management practices of subalpine forests in eastern Tibetan Plateau.

以25个平欧杂种榛品种(系)为试验材料,开展坚果经济性状变异和分级研究,并对坚果经济性状进行综合评价.结果 表明,供试平欧杂种榛品种(系)坚果、果仁质量分别在0.81～3.36 g和0.27～1.10 g,坚果、果仁三径均值分别在13.11～19.75mm和8.17～13.89 mm,果壳厚度、果腔系数和出仁率分别在0.74～2.39mm、0.53～0.93和21.90％～46.04％,果序坐果数、单株结果数和单株产量分别在1.4～4.7个、81.0～620.7个和123.9～1 064.4 g.不同平欧杂种榛品种(系)各经济性状指标之间的差异显著,其中,坚果、果仁质量和整齐度、单株结果数和产量变异系数在31.5％～55.2％,在品种选育时其可选性强;坚果、果仁形状变异系数在5.8％～9.2％,选择空间最小.通过聚类分析,供试平欧杂种榛被划分为3个类群.主成分分析表明,果仁大小和整齐度是影响供试平欧杂种榛坚果综合经济性状的最重要指标,其次为果壳厚度,85-124、82-8、85-41、85-202、84-5、85-140和84-254等品种(系)的坚果综合经济性状较优.

以新疆伊犁地区引种栽培的33个平欧杂种榛品种(系)为材料,对其雌、雄花的开花时间、花期长度以及试验地温度进行调查观测,通过聚类分析等方法评价不同品种(系)平欧杂种榛开花物候期的特点和差异.结果表明:伊犁地区平欧杂种榛的雌、雄花一般于3月初开花,雄花萌动期相差不大,雌、雄花于3月中旬进入盛花期,3月底左右到达终花期.雄花的花期长度为10～22 d,雌花的花期长度为13～20 d.不同品种(系)平欧杂种榛的雄花松动期和雌花初期的时间较为分散,而雄花终期和雌花盛期的时间较为集中.各品种(系)平欧杂种榛雌花的物候期一般都与雄花的物候期存在重叠,相遇期8 d,可以保证正常授粉.2018年伊犁地区春季气温回升较快,花期内温度变化较大,是影响各品种(系)平欧杂种榛花期差异的主要原因之一.通过聚类分析,可将33个品种(系)平欧杂种榛分为4类.

为明确吡唑醚菌酯、丙环唑和戊唑醇3种杀菌剂对榛子(Corylus heterophlla)苗期根腐病的防治效果,采用菌丝生长速率法分别测定3种杀菌剂对榛子根腐病菌的抑菌效果,通过田间灌根处理比较3种杀菌剂对榛子根腐病的防效.结果表明:3种杀菌剂对榛子根腐病菌毒力最高的是吡唑醚菌酯,EC50为0.0539 mg·L-1,丙环唑次之,EC50为0.0551 mg·L-1,戊唑醇的毒力最低,EC50为0.0747 mg·L-1.田间施药30 d后,吡唑醚菌酯(有效剂量60 mg·L-1)防治效果最高,为93.99％;戊唑醇(有效剂量50 mg·L-1)防效次之,为90.94％;丙环唑(有效剂量10 mg·L-1)防效最低,为84.50％.施药60 d和90 d的防效较30 d的略低,防治效果趋于稳定.3种杀菌剂对榛子苗期根腐病菌均具有明显的抑菌和防治效果,其中吡唑醚菌酯和戊唑醇可作为榛子苗期根腐病防治的首选药剂.

利用新疆40个气象台站连续10a(2009-2018年)气象数据年平均气温和地理信息资料,选取海拔、年平均气温、年均降水量、日照时数4个因子作为区划指标;采用多元回归,建立气象因子的空间模型,利用地理信息系统(GIS)技术对4个因子参数进行数据网格插值分析;根据层次分析法(AHP)计算指标权重值,利用GIS叠加分析功能,得到平欧杂种榛适生区专题图.结果 表明:平欧杂种榛种植区分为最适宜区、适宜区、次适宜区、不适宜区;最适宜区面积为27.722×104km2,占新疆土地总面积的16.7％,主要分布在喀什地区、阿克苏地区、伊犁河谷、昌吉回族自治州、乌鲁木齐市、巴音郭楞蒙古自治州北部、吐鲁番地区以及哈密地区北部;适宜区面积为69.056×104km2,占新疆土地总面积的41.6％,主要分布在喀什地区、克孜勒苏柯尔克孜自治州、和田地区北部、巴音郭楞蒙古自治州北部、阿克苏地区、塔城地区以及阿勒泰部分地区.

[目的]以新疆9年生的平欧杂种榛为研究对象,探讨氮、磷、钾不同施肥量对平欧杂种榛光合特性、产量和品质的影响,为新疆榛子产业发展提供合理施肥依据.[方法]采用“3414”田间肥料效应试验,测定氮、磷、钾不同施肥配比条件下对果仁膨大期榛子叶片的叶绿素含量和叶绿素最大光能转化效率的日变化及对产量和品质的响应.[结果]表明:平欧杂种榛的叶绿素相对含量(SPAD)随着N肥的增加而增加;T5(N2P1K2)对Fo、Fv和Fm有显著调控作用;T9(N2P2K1)榛果的纵径、横径、侧径、单果质量、果仁质量及出仁率比T1(N0P0K0)分别平均增加9.96％、9.77％、11.99％、31.94％、10.13％和5.56％,粗脂肪和粗蛋白比T1分别平均增加11.56％和16.67％.[结论]在新疆土壤养分中等条件下,N、P2O5、K2O施肥量纯量分别为1 205.6、485.00、329.3 kg·hm-2时,榛果达到了优质高产,有利于提高新疆平欧杂种榛的经济效益.

[目的]研究氮磷钾配施对平欧杂交种榛果实发育时期光合特性和产量的影响,为提高平欧杂种榛产量、改善品质提供科学参考.[方法]以8年生新榛1号为材料,采用"3414"田间肥料效应试验,测定不同施肥配比条件下榛子果实发育时期的叶片光合特性和产量.[结果](1)在土壤中等条件下,施用适量的N肥可以提高新榛1号果实坐果期(N纯量<0.71 kg/株)、速生生长期(N纯量<0.95 kg/株)、脂化期(N纯量<0.89 kg/株)和成熟期(N纯量<0.66 kg/株)的净光合速率(Pn);施用适量P肥可以提高果实脂化期(P纯量<0.29 kg/株)的净光合速率;施用适量K肥可以提高果实速生生长期(K纯量<0.25 kg/株)的净光合速率.(2)N肥与P肥的交互作用(N×P)可以提高果实速生生长期的净光合速率,但会降低新榛1号果实坐果期、脂化期、成熟期的净光合速率;N肥与K肥的交互作用(N×K)会降低果实速生生长期、脂化期的净光合速率;P肥与K肥的交互作用(P×K)会降低果实成熟期的净光合速率.[结论]平欧杂种榛果实发育时期N肥、P肥、K肥施肥(纯量)分别为0.81、0.23和0.19 kg/株.经换算,尿素、重过磷酸钙、硫酸钾施肥量分别为1.75、0.50和0.37 kg/株.

Although variation of floral organ numbers has been a prevalent phenomenon during the evolution of zygomorphic flowers among many species, most legumes in the subfamily Papilionoideae possess pentamerous corollas. Previous work showed that dorsoventral asymmetrically expressed CYCLOIDEA (CYC)-like genes have been recruited to the establishment of floral zygomorphy. However, the mechanism determining petal number along the dorsoventral axis remains unknown. Here we address this question by a comparative study of floral development between two papilionoid legumes and characterization of two new genetic loci, KEEL LOSS1 (KEL1) from Lotus japonicus and RED BULL1 (REB1) from pea (Pisum sativum L.). kel1 and reb1 mutants show varying degrees of petal absence along the dorsoventral axis, resembling diverse floral morphologies in legumes with non-pentamerous corollas. Ontogenetic analysis shows that the kel1/reb1 phenotype is caused by the defect of early stage common primordia shared between petal and stamen. KEL1 and REB1 are orthologs encoding APETALA2 (AP2) type transcription factors and are both expressed in the ventral or ventral/dorsal region of the floral meristem, consistent with the predominant absence of petals at the corresponding positions in respective mutants. We also find that KEL1 is independent of the CYC pathway, and interacts with PROLIFERATING FLORAL ORGANS (PFO) to control the common primordia indeterminacy by regulating LjWUSCHEL and LjAGAMOUS expression in L. japonicus. We conclude that KEL1/REB1 regulates position-specific floral patterning and confers robust petal numbers along the dorsoventral axis in papilionaceous flowers. While its major role of controlling petal number is largely conserved between L. japonicus and pea, loss of KEL1 in different ontogenetic or genetic background often leads to distinct floral morphologies, suggesting that KEL1 may be a key dorsoventral factor driving the evolution of legume flowers.

In contrast to typical radially symmetrical flowers, zygomorphic flowers, such as those produced by pea (Pisum sativum L.), have bilateral symmetry, manifesting dorsoventral (DV) and organ internal (IN) asymmetry. However, the molecular mechanism controlling IN asymmetry remains largely unclear. Here, we used a comparative mapping approach to clone SYMMETRIC PETALS 1 (SYP1), which encodes a key regulator of floral organ internal asymmetry. Phylogenetic analysis showed that SYP1 is an ortholog of Arabidopsis thaliana LIGHT-DEPENDENT SHORT HYPOCOTYL 3 (LSH3), an ALOG (Arabidopsis LSH1 and Oryza G1) family transcription factor. Genetic analysis and physical interaction assays showed that COCHLEATA (COCH, Arabidopsis BLADE-ON-PETIOLE ortholog), a known regulator of compound leaf and nodule identity in pea, is involved in organ internal asymmetry and interacts with SYP1. COCH and SYP1 had similar expression patterns and COCH and SYP1 target to the nucleus. Furthermore, our results suggested that COCH represses the 26S proteasome-mediated degradation of SYP1 and regulates its abundance. Our study suggested that the COCH-SYP1 module plays a pivotal role in floral organ internal asymmetry development in legumes.

溯源侵蚀作为黄土高原最为活跃的沟谷侵蚀方式,是导致塬面萎缩和破碎化的主要原因,对黄土塬区的国土安全、民生安全和生态安全构成了严重威胁.董志塬是黄土高原面积最大、最为连续的塬面,但随着人类活动的不断增强尤其是城市化的快速发展,董志塬溯源侵蚀剧烈,完整的塬面被不断切割.本文以董志塬西峰城区火巷沟(35°44′24″N,107°39′03″E)为例,采用GIS与RS技术,通过对1964～2017年的7期高精度遥感影像进行解译分析,定量研究了1964年以来火巷沟沟头前进、后退和沟岸扩张的动态特征及其与城市发展和降雨因素的关系.研究结果表明:1)1964～1969年,火巷沟沟头平均每年以3.1 m的速度前进;1970～2002年,由于城区的发展和扩张,沟头因人工回填后退了359.8 m;2003～2017年,随着城市建设用地的进一步扩大,15年间沟头因回填后退了178.3 m;2)1964～2017年,火巷沟沟岸不断向两侧扩张.1964～1966年平均每年向外扩张1.1 m,1967～1969年每年扩张1.4 m,1970～2002年每年扩张1.1 m,2003～2008年每年扩张2.9 m,2009～2014年每年扩张8.0 m,2015～2017年每年扩张2.7 m;3)1964～2017年,西峰城区面积由2.1 km2扩大至19.8 km2,城区面积的不断扩大与火巷沟沟岸的扩张呈显著正相关关系;西峰城区与火巷沟沟头在早期接触面积较小,而现今随着城市的扩张,火巷沟沟头已被城区包围,致使沟道周围汇水能力增强冲刷沟岸,导致沟岸不断向外扩张;4)因受沟岸扩张和降雨数据时间分辨率的影响,本研究没有发现降雨与沟岸扩张之间存在明显的相关关系.本研究对深入认识黄土塬区城市化影响下沟头侵蚀演变特征和固沟保塬具有重要的参考意义.