UV-absorbing compounds and susceptibility of weedy species to UV-B radiation   总被引：3，自引：0，他引：3  

QIUJIE DAI  NANCY H. FURNESS  MAHESH K. UPADHYAYA 《Weed Biology and Management》2004,4(2):95-102

Stratospheric ozone (O₃) depletion has led to increased terrestrial ultraviolet‐B (UV‐B) radiation (290–320 nm). Leaves exposed to this radiation produce UV‐absorbing compounds in the epidermal cells, which protect plants from UV‐B damage. To determine the role of UV‐absorbing compounds in the UV‐B sensitivity of weeds (common chickweed (Stellaria media), downy brome (Bromus tectorum), green smartweed (Polygonum scabrum), redroot pigweed (Amaranthus retroflexus), spotted cat’s‐ear (Hypochoeris radicata), and stork’s‐bill (Erodium cicutarium)) seedlings were exposed to 0, 4 (field ambient), 7 (18% O₃ depletion) and 11 (37% O₃ depletion) kJ m^?2 d^?1 of biologically effective UV‐B radiation in a greenhouse. Ultraviolet‐absorbing compounds were extracted from the second true‐leaf (0.5 cm² samples) with methanol : distilled water : HCl (79 : 20 : 1) in an 85°C water bath for 15 min, and the absorbance of the extracts measured at 300 nm. The shoot dry biomass was recorded to determine the susceptibility to UV‐B radiation. Common chickweed was the most sensitive and green smartweed the least sensitive weed to UV‐B radiation. The latter accumulated more UV‐absorbing compounds and this accumulation occurred earlier compared with common chickweed. As UV‐B_BE radiation levels increased from 0 to 11 kJ m^?2 d^?1, the green smartweed shoot biomass did not decline. However, the biomass of all five susceptible species declined despite an increase in the UV‐absorbing compounds in response to increased UV‐B radiation. Therefore, formation of a ‘UV‐screen’ in these species is not sufficient to fully prevent UV‐B damage. When the concentration of UV‐absorbing compounds in the six species was plotted against their susceptibility to UV‐B radiation, no relationship was observed. Thus, while the accumulation of UV‐absorbing compounds may be a major factor in the protection of certain species against UV‐B radiation and may offer some degree of defence in other species, it does not explain UV‐B susceptibility differences in weedy species in general.  相似文献   

云南温带多年生优良牧草——扁穗雀麦     

崔茂盛  徐桂芬  徐驰 《草业与畜牧》2011,(6)

分析总结了扁穗雀麦的分布、来源、植物学特征、生物学特性、饲用价值和栽培利用措施,以促进该优良牧草的推广利用。由于扁穗雀麦在云南冬春潮湿阴凉环境条件下仍保持绿色,故可作为解决冬春青绿饲料的优良牧草利用。  相似文献   

生境对无芒雀麦幼穗分化进程及生殖格局的影响     

陈映霞  杜雨  王玉祥  张博  阿迪莱·阿布都热合曼 《草业学报》2023,32(1):112-121

以乌苏1号无芒雀麦为材料,设置2个生长环境（荒漠绿洲区、高海拔地带）,通过观测幼穗分化进程及开花习性,探究生境对无芒雀麦幼穗分化及生殖格局的影响。结果表明,无芒雀麦幼穗分化从分蘖期开始至抽穗期结束,分为初生期、伸长期、结节期、小穗原基分化期、小花原基分化期、雌雄蕊原基分化期、雌雄蕊形成期和完穗期8个时期。幼穗分化是从生长锥顶端第1枝梗原基与小花原基开始分化,相同小枝梗上原基与小花原基均是自下逐渐向上发育;整穗是从顶部向下逐渐开花,下部枝梗开花时间小于上部枝梗;小穗上的小花由下向上逐步开花。与荒漠绿洲区相比,高海拔地带的无芒雀麦幼穗分化时间晚,周期缩短,穗部赤霉素（GA）、脱落酸（ABA）及叶片可溶性蛋白含量相对较高,细胞分裂素（CTK）含量和种子千粒重较低,但高海拔地带单穗成熟种子粒数与单位面积内种子产量高,更适合无芒雀麦种子生产。  相似文献   

盐胁迫对5份无芒雀麦苗期生长和生理生化的影响及综合性评价     

李瑞强  王玉祥  孙玉兰  张磊  陈爱萍 《草业学报》2023,32(1):99-111

为了明确不同无芒雀麦苗期耐盐能力的强弱,本研究选择5份不同株型的无芒雀麦作为供试材料。根据新疆土壤盐碱成分设置中性盐(M盐)：NaCl∶Na₂SO₄∶Na₂CO₃=1∶4∶0和碱性盐(A盐)：NaCl∶Na₂SO₄∶Na₂CO₃=1∶1∶8两种处理,于三叶期每盆一次性浇灌2 L电导率(EC)为20 ms·cm^-1的盐处理液,CK浇灌等量自来水。处理30 d后测定生长指标、叶绿素荧光特性参数、丙二醛(MDA)和渗透调节物质含量,并通过相关性分析、主成分分析、隶属函数分析对13个指标进行分析评价。结果表明：除F_v/F_m和F_v/F_o外,盐胁迫显著影响其余11个指标,且5份材料间差异显著(P<0.05);5份无芒雀麦的株高、茎粗、分蘖数、地上生物量、根冠比、MDA和脯氨酸含量在不同盐胁迫下表现出不同的适应变...  相似文献   

用钙电极测定牧草中钙含量的方法研究   总被引：1，自引：0，他引：1  

刘福林 《草业科学》1996,13(6):24-25

用钙电极测定禾本科牧草中钙含量的方法，回收率１００．０２％－９７．３８％，用高酸钾法的ＥＤＴＡ法与钙电极法作比较试验，结果非常满意。  相似文献   

11份无芒雀麦苗期耐盐性评价     

孙桂枝  王赞  张耿  于遵波  高洪文 《四川草原》2007,(3)

对11份引自俄罗斯的野生无芒雀麦(Bromus inermis Leyss.)材料,在0.3%、0.4%、0.5%NaCl胁迫下,通过存活率、总生物量、叶片伤害率、株高的测定,采用隶属函数法和标准差系数赋予权重法进行耐盐性综合评价。结果表明:供试11份无芒雀麦在0.3%、0.4%、0.5%NaCl胁迫下存活率分别为90%～100%,76.7%～96.7%,67.0%～96.7%;根据耐盐性综合评价值(D)得出供试材料耐盐性顺序为,ZXY04P-371>ZXY04P-255>ZXY04P-136>ZXY04P-188>ZXY04P-96>ZXY04P-503>ZXY04P-34>ZXY04P-322>ZXY04P-241>ZXY04P-46>ZXY04P-18。  相似文献   

灌溉对华北农牧交错带无芒雀麦生物学特性的影响   总被引：1，自引：0，他引：1  

王琥  李向林  万里强  王国良  何峰 《草原与草坪》2007,(5):32-36

研究了河北坝上地区不同水分处理下无芒雀麦的生物学特性。结果表明,不同水分处理对无芒雀麦的植株高度、分蘖数、叶面积、地上和地下植物量等生物学特性均有不同程度的影响。在9月初刈割前,植株高度顺序为W3>W4>W2>W1,表明较多的灌水有利于植株的生长;叶面积大小顺序与植株高度变化规律相似,叶面积大小顺序为W4>W3>W2>W1,表明较多的灌水利于叶片的增大;对于分蘖数则相反,不同水分处理分蘖数顺序为W1>W2>W3>W4,灌水越多分蘖越少,说明整个生长季里适当的干旱可以促进分蘖;不同水分处理下地上植物量的大小次序为W2>W4>W3>W1,但无显著差异;不同水分处理根系重量的大小次序为W2>W1>W3>W4,说明适当干旱有利于无芒雀麦根系的生长。  相似文献   

无芒雀麦人工草地初级生产力动态的研究   总被引：3，自引：0，他引：3  

郭孝 《草业科学》1997,14(3):21-24

以无芒雀麦人工草地为研究对象，对其生物量的季节及垂动态进行连续４ａ的研究。为促进无芒雀麦草地在河南省的高产丰收提供基础资料及其理论依据。  相似文献   

Longevity of seeds of four annual grass and two dicotyledon weed species as related to placement in the soil and straw disposal technique     

P K JENSEN 《Weed Research》2009,49(6):592-601

Persistence of seeds of the four winter annual grass species, Alopecurus myosuroides , Bromus sterilis , Bromus hordeaceus and Vulpia myuros , were studied under field conditions. The studies also included the two dicotyledon species, Tripleurospermum inodorum and Galium aparine . Seed samples were stored in the field at different depths in the plough layer for a year. Following germination, seedling emergence was taken as an indicator of field persistence. In a supplementary investigation, seed samples were placed on the soil surface or buried at 2 cm for a month and then tested for viability. Persistence of the two Bromus species was very short, irrespective of depth and duration of burial. Persistence of the other species was positively correlated with incorporation of seeds to a few centimetres depth. Increasing the depth of incorporation below 2 cm had a variable influence on persistence. Persistence of seeds placed directly on the soil surface was short, whether they were left there for a year or a month. Whether seeds at the soil surface were left uncovered or covered with chopped straw had limited influence on seed persistence. However, straw cover significantly increased persistence of A. myosuroides seeds and there was the same tendency with T. inodorum .  相似文献   

混播比例和刈割期对混播草地产草量及种间竞争的影响   总被引：4，自引：1，他引：3  

锡文林  张仁平 《中国草地学报》2009,31(4)

对新疆石河子绿洲区紫花苜蓿与无芒雀麦混播草地的群落生物量、茎叶比、种间竞争力进行了动态研究.结果表明,以紫花苜蓿7.5kg/hm2、无芒雀麦15kg/hm2的比例混播并在紫花苜蓿初花期刈割为最佳组合,干物质产量为23.4t/hm2.两种牧草种间竞争力和竞争率分析表明,不同的混播比例和刈割期对两种牧草的竞争力有一定影响,紫花苜蓿的竞争力强于无芒雀麦,在竞争中占有优势.  相似文献