盐胁迫下三角叶滨藜根系超滤特性的分析

对耐盐蔬菜三角叶滨藜(Atriplex triangularis)在盐胁迫下的蒸腾吸水量、Na+吸收和根系径向反射系数进行了测定,分析其根系超滤特性与植物耐盐性的关系。结果表明,随着盐胁迫强度的增加,三角叶滨藜的Na+吸收量逐渐增多、蒸腾吸水量和根系径向反射系数则逐渐降低;但以根外溶液盐浓度为基础的Na+相对吸收量却呈降低趋势,同时进入木质部的Na+的量也不随根的径向反射系数的减小而显著增多。说明三角叶滨藜在盐胁迫下一方面通过改变根系的超滤特性,降低根系径向反射系数来防止木质部拉力过大导致的木质部空化的危险,另一方面通过减少对盐分的吸收来避免盐分过多积累对植株的伤害。     

Biomass Production,Forage Quality,and Cation Uptake of Quail Bush,Four‐Wing Saltbush,and Seaside Barley irrigated with Moderately Saline–Sodic Water

Abstract: Beneficial use of water of impaired quality has gained attention globally as society's demand for domestic quality water has increased. Additionally, concerns about the environmental implications of disposal of water of impaired quality have necessitated assessment of alternatives to disposal of such water. The study reported here investigated capacity of Atriplex lentiformis (Torr.) S. Wats. (Quail bush), Atriplex X aptera A. Nels. (pro sp.) (Wytana four‐wing saltbush), and Hordeum marinum Huds. (seaside barley) to produce biomass and crude protein and take up cations when irrigated with moderately saline–sodic water, in the presence of a shallow water table. Water tables were established at 0.38, 0.76, and 1.14 m below the surface in sand‐filled columns. The columns were then planted to the study species. Study plants were irrigated for 224 days; irrigation water was supplied every 7 days equal to water lost to evapotranspiration (ET) plus 100 mL (the volume of water removed in the most previous soil solution sampling). Water representing one of two irrigation sources was used: Powder River (PR) [electrical conductivity (EC) = 0.19 Sm^?1, sodium adsorption ratio (SAR) = 3.5 (mmol_c L^?1)^1/2 ] or coalbed natural gas (CBNG) wastewater [EC = 0.35 Sm^?1, SAR = 10.5 (mmol_c L^?1)^1/2]. Biomass production did not differ significantly between water quality treatments but did differ significantly among species and water table depth within species. Averaged across water quality treatments, Hordeum marinum produced 79% more biomass than A. lentiformis and 122% more biomass than Atriplex X aptera, but contained only 11% crude protein compared to 16% crude protein in A. lentiformis and 14% crude protein in Atriplex X aptera. Atriplex spp. grown in columns with the water table at 0.38 m depth produced more biomass, took up less calcium (Ca²⁺) on a percentage basis [(g Ca²⁺ g^?1 biomass) ×100], and took up more sodium (Na⁺) on a percentage basis than when grown with the water table at a deeper depth. Uptake of cations by Atriplex lentiformis was approximately twice the uptake of cations by Atriplex X aptera and three times that of H. marinum. After 224 days of irrigation, crop growth, and cation uptake, followed by biomass harvest, EC and SAR of shallow groundwater in columns planted to A. lentiformis were less than EC and SAR of shallow ground water in columns planted to either of the other species.     

Effects of seed treatments on the germination of Atriplex nummularia Lindl.

Laboratory experiments were conducted to determine the influence of length of soaking period and water temperature treatments on the germination of Atriplex nummularia. Germination percentages increased significantly (P≤0,01) with increasing soaking period in water with a temperature of 20°C, while there was a tendency for a decrease in germination at the higher water temperature (30°C) treatment. The fruits were almost fully imbibed after 8 days of soaking at both water temperature treatments. Fruits germinated better in pots than in petri dishes, but for naked seeds the opposite was the case. Some of the unexplained findings should be further investigated.     

Evaluation of shrub species for sheep grazing in the Strandveld of the Cape West Coast of South Africa

The production of three exotic shrub species, Atriplex nummularia (old man saltbush), A. canescens (four‐winged salt‐bush) and Medicago arborea (tree lucerne) and one indigenous evergreen shrub, Chrysanthemoides monilifera subsp. pisifera (west coast bitou), was evaluated in the Strandveld of the Cape West Coast in terms of grazing capacity (ssu ha^?1) and average daily gain (ADG) (g ssu^?1 day^?1) using mature Dorper sheep. Medicago arborea died out during the first season. The other three shrubs, however, survived and over a seven‐year period mean grazing capacities of 1.7, 1.6 and 1.0 ssu ha^?1 were obtained, respectively, for C. monilifera, A. nummularia and A. canescens, which is in excess of the area norm of 5 ha ssu^?1 for natural veld. Positive ADGs of 80 and 30 g ssu^?1 day^?1 were obtained on A. nummularia and A. canescens, respectively, but not on C. monilifera (‐180 g ssu^?1 day^?1).     

用正交设计优化四翅滨藜的育苗方法

用正交试验设计的方法,探讨了四翅滨藜播种育苗和扦插育苗中的一些主要影响因子。结果表明,覆盖方式对播种试验结果的影响程度最大,适宜的播种育苗方案为:清水浸种24h,在耕作土与过筛河沙体积比为1∶2的基质中播种,深度为1~2cm,播种后用遮阳网遮阴;取材的部位对扦插成活率的影响程度最大,适宜的扦插育苗方案为:取半木质化(枝条中上部)的长为8~10cm插穗,在200 m g/L ABT1溶液中浸泡1h,在耕1∶沙2的基质中扦插。     

Salinity Reduces the Forage Quality of Forage Kochia: A Halophytic Chenopodiaceae Shrub

Forage kochia (Bassia prostrata [L.] A.J. Scott) is a perennial, halophytic Chenopodiaceae shrub adapted to semiarid rangelands and steppes. It is noted for its ability to produce edible forage in saline environments, but the effect of salinity on its nutritive value has not been determined. Therefore, this study evaluated the dose-response of increasing salinity on the forage quality of forage kochia and Gardner’s saltbush (Atriplex gardneri [Moq.] D. Dietr., a chenopod forage shrub indigenous to the United States). Individual plants were evaluated in hydroponics for 28 days at 0, 150, 300, and 600 mM NaCl. Salt from accumulated ions, minerals, and forage nutritive value were determined using ground shoot samples. Analysis of forage nutritive value is problematic in plants with high salt concentrations, so neutral detergent fiber (NDF) and in vitro true digestibility (IVTD) were also predicted on an ash-corrected dry matter (DM) basis (NDF_corrected and IVTD_corrected). Forage kochia exhibited a dose-response for salt concentration, IVTD_corrected, and crude protein (CP) as salinity increased. Salt concentrations increased to 19% of DM at 600 mM NaCl, which may reduce voluntary intake by ruminants grazing forage kochia. Results indicated that uncorrected IVTD estimates were inflated as forage kochia IVTD_corrected decreased from 65% to 56% with the major change between 300 and 600 mM NaCl. Crude protein did not differ between two forage kochia cultivars but decreased from 26% to 15% between 0 and 600 mM NaCl, whereas Gardner’s saltbush CP decreased by only five percentage points as salinity increased. Nonetheless, despite the greater CP sensitivity to salinity level, forage kochia salt concentration was less and digestibility and metabolizable energy (ME) were greater than Gardner’s saltbush. Overall, salinity reduced the forage quality of forage kochia, though not as dramatically as for Gardner’s saltbush, thus supporting use of forage kochia to improve the forage base of saline rangelands.     

Organic Carbon and Alkalinity Increase in Topsoil After Rangeland Restoration Through Atriplex nummularia Plantation

This research studied the impact of fodder shrub plantations (Atriplex nummularia Lindl.) on topsoil properties, with particular reference to organic carbon, nitrogen, and soluble salts, in the Marrakech region (central Morocco). The studied plantation interventions were carried out to rehabilitate degraded rangeland and to mitigate desertification. The field experiment was conducted by drawing seventeen 50‐m‐long transects designed according to the ecological patch–interpatch approach defined by the Landscape Function Analysis. The top soil (0–5 cm) was sampled in 134 microsites, covering the main patch and interpatch types in plantation and control plots. The following variables were determined: pH, carbonates, organic carbon, total nitrogen, electrical conductivity, and soluble ions (Na⁺, K⁺, Ca²⁺, Mg²⁺ Cl⁻, NO₃⁻, SO₄²⁻ and PO₄³⁻). Statistical analyses were carried out to analyse changes between sites and between patch types. Most of the studied properties were strongly affected by the spatial pattern defined by the plantation, particularly when the sites with higher biomass production were considered. Organic carbon increased by around 63% and 117% when the under canopy patches were compared, respectively, to the between‐plants interpatches and to the control plots, a strong positive effect considering the aridity of the study area. On the other hand, a stronger increase was detected under canopy for most soluble salts and sodium adsorption rate. On average, the latter increased by 350% and up to 450% under the best developed plants, a stronger impact than observed in previous research, highlighting the very strong plant effect on the soil surface alkalinity. Copyright © 2015 John Wiley & Sons, Ltd.     

干旱胁迫对木本滨藜生理特性的影响

以2年生的努塌滨藜、三角滨藜、四翅滨藜、沙棘为试材,研究干旱胁迫条件下木本滨藜生理特性的影响。结果表明:1)3种木本滨藜植物通过维持较高的束缚水含量来增加保水能力,沙棘束缚水含量及保水能力远低于木本滨藜。2)干旱胁迫条件下努塌滨藜、三角滨藜细胞膜受氧化程度较小,四翅滨藜在重度干旱条件下MDA含量比对照增加了19.3%,细胞膜受氧化程度较大;3种滨藜植物在干旱胁迫下,膜透性没有明显升高,细胞膜结构与功能完好,而沙棘在中度干旱胁迫下MDA含量比对照增加了20.68%,严重干旱胁迫时增加24.34%,且与对照有显著性差异,细胞膜受严重氧化,造成细胞透性在中度、重度干旱胁迫下较正常水分条件下分别增大37.38%和41.58%,细胞膜系统受到较为严重伤害。3)干旱胁迫对滨藜植物光合色素合成影响不明显,而沙棘在严重干旱条件下Chla降低了27.76%(P<0.05),Chlb降低44.18%(P<0.01),叶绿素合成受到抑制。4)根据Farquhar等提出的气孔限制值分析观点判断,除了中度干旱胁迫下三角滨藜Pn下降可能是非气孔限制因素造成以外,其他Pn下降可能是气孔关闭造成。5)利用隶属函数对4种植物抗旱能力评价由高到...     

盐胁迫对木本滨藜叶绿素合成及净光合速率的影响

为了对盐碱地植被恢复及改造提供优良植物资源,该文以三角滨藜、努塌滨藜、四翅滨藜为研究对象,沙棘和白榆为对照,进行NaCl、Na2SO4胁迫处理,并对比分析不同盐分含量对其叶绿素含量、净光合速率及生长的影响。结果表明:1)不同盐分胁迫对3种木本滨藜叶绿素合成的影响均小于沙棘和白榆。2)3种木本滨藜净光合速率受胁迫影响程度明显小于沙棘和白榆,在高浓度盐土的胁迫下,保持较高净光合速率,维持正常新陈代谢,表现较强的抗逆性。3)3种木本滨藜在盐胁迫下,株高和基径所受影程度明显小于沙棘和白榆。5种植物株高和基径随盐分梯度变化规律与植物光合速率变化规律相一致。4)利用隶属函数对5种植物抗盐能力进行综合评价得出,抗NaCl盐分胁迫能力大小顺序为:努塌滨藜>三角滨藜>四翅滨藜>沙棘>白榆;抗Na2SO4盐分胁迫能力大小顺序为:四翅滨藜>三角滨藜>努塌滨藜>沙棘>白榆,表明3种木本滨藜在植物光合作用及生长方面表现出极强抗盐能力,有很强的推广应用价值,是中国盐碱地利用的优质植物资源,该文研究可为中国北方旱区盐碱地利用提供理论依据。