60Co-γ射线对2种狼尾草属牧草的诱变效应

目的 探究 ⁶⁰Co-γ射线对“热研4号”杂交狼尾草及“华南”象草的诱变效应,创制新种质,以推动狼尾草的育种工作。 方法 在前期剂量筛选基础之上,以2种狼尾草品种（“热研4号”杂交狼尾草和“华南”象草）种茎为材料,利用 ⁶⁰Co-γ射线进行辐射,剂量为30 Gy,剂量率为1 Gy·min ^-1。将辐射后的种茎与未辐射的种茎栽植于大田中,常规田间管理,1个月后统计成活率。待成活的植株生长成熟后,在2个诱变系群体中分别随机挑选30株进行形态指标的测定,共测定7个指标。随后利用分子标记探究辐射对遗传变异的影响。 结果 2个品种的辐射材料,分别随机选取30株进行形态指标测定,与对照相比,发现“热研4号”诱变系中有28株的株高,21株的茎节数及17株的叶宽有显著或极显著差异。“华南”诱变系中有20株的株高有显著或极显著差异,其他形态指标差异不大。2种牧草的突变体大都表现出株高的降低,因此,生物量也随之减少。还发现一个辐射材料RY4-17,由于分蘖数多于对照导致生物量增加。SSR分子标记研究结果表明,在“热研4号”诱变系中,20对引物的平均多态信息含量为0.245,共扩增出83条带,其中多态性条带52条,诱变系与对照之间的遗传相似系数为0.67—0.89,平均值为0.81,差异位点数为9—27,平均为15.9个,UPGMA聚类结果显示突变体RY4-9和RY4-23与对照遗传距离最远,变异程度最大。在“华南”诱变系中,20对引物的平均多态信息含量为0.394,共扩增出81条带,其中多态性条带65条,诱变系与对照之间的遗传相似系数为0.54—0.86,平均值为0.77,差异位点数为10—38,平均为18.8个,UPGMA聚类结果显示突变体HN-24与对照遗传距离最远,变异程度最大。结论 适宜剂量的 ⁶⁰Go-γ射线辐射可以使2种牧草种茎成活率显著降低,同时可以有效诱导2种牧草在形态学和遗传学水平上发生变异。 ⁶⁰Go-γ射线辐射诱变是解决狼尾草因无性繁殖为主而导致遗传资源多样性匮乏的有效途径。     

Alleviative effects of mixed-cropping with rice on the growth inhibition of pearl millet caused by flooding at reproductive stage

Flooding has globally become common, and thus cultivation techniques to adapt to the stress are required. We have developed a technique called “close mixed-planting” using flood-adapted rice (Oryza sativa L.) and upland crops with tangled root systems, showing that this technique can mitigate the damage caused to upland crops by flooding. However, the plant response during the reproductive stage has not yet been examined. In this study, we estimated the alleviative effects of close mixed-planting on the growth inhibition and physiological damage to pearl millet (Pennisetum glaucum) caused by flooding at the reproductive stage in northern Namibia. Pearl millet and NERICA4 (Oryza spp., interspecies of O. sativa and O. glaberrima) were used. Four-week-old single- and mixed-crop pearl millets were transplanted and grown for 22 days, and then flooding treatment was administered for 28 days. The growth and physiological parameters of single pearl millet were significantly decreased by flooding stress, and the parameters did not recover during a 14-day recovery period compared with those of unflooded single and mix-cropped pearl millet. On the other hand, the damage to mix-cropped pearl millet by flooding was suppressed. Thus, the mixed-cropping mitigated the anoxic stress of pearl millet caused by flooding at the reproductive stage and contributed to the improved growth after the recovery period. This result suggested that the close mixed-planting with rice can contribute to the mitigation of flooding damage not only at the vegetative stage but also at the reproductive stage of pearl millet in the semi-arid African country, Namibia.     

王草中水不溶性膳食纤维制备工艺研究

为提高王草综合利用水平,以王草为原料,采用化学水解法制备王草水不溶性膳食纤维,并探讨过氧化氢对其漂白效果的影响,测定其理化性质。结果表明,王草水不溶性膳食纤维最佳提取工艺条件为:提取温度55℃,NaOH质量浓度40g/L,提取时间120 min。该条件下提取率最高达到46.52%;最佳漂白工艺为过氧化氢浓度40 mL/L,时间2 h,温度50℃,pH值为9;王草水不溶性膳食纤维的膨胀力4.26 mL/g,持水力5.64 g/g。     

Seed parent breeding efficiency of three diverse cytoplasmic-nuclear male-sterility systems in pearl millet

Pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids, grown widely in India and to some extent in the US, are all based on an A₁ CMS source, leaving the pearl millet hybrids vulnerable to potential disease or insect pest epidemics. A comparison of this CMS system with two additional CMS systems (A₄ and A₅) in the present study based on isonuclear A-lines (seed parents) and their isonuclear hybrids showed that A-lines with the A₄ cytoplasm had much fewer pollen shedders and much reduced selfed seed set in visually assessed non-shedding plants as compared to those with the A₁ cytoplasm. A-lines with the A₅ cytoplasm had neither any pollen shedders nor did they set any seed when selfed. This showed that the A₅ CMS system imparts complete and most stable male sterility, followed by the A₄ and A₁ CMS systems. The frequency of maintainers, averaged across a diverse range of 26 populations, was highest for the A₅ CMS system (98%), followed by the A₄ (59%) and the A₁ (34%) system indicating the greatest prospects for genetic diversification of A-lines lies with the A₅ cytoplasm, and the least with the A₁ cytoplasm. Mean grain yield of hybrids with the A₁ cytoplasm was 5% more than the A₄-system hybrids, while there was no difference between the mean grain yield of hybrids based on A₁ and A₅ CMS systems. Based on these results, it is suggested that seed parents breeding efficiency will be the greatest with the A₅ CMS system, followed by the A₄ CMS system, and least with the currently commercial A₁ CMS system.     

纤维素酶与木聚糖酶对象草青贮发酵品质的影响

为研究纤维素酶与木聚糖酶对象草(Pennisetum purpureum Schumach.)青贮品质的影响,本试验共设6组:T1:象草+500 mg·kg-1纤维素酶;T2:象草+250 mg·kg-1纤维素酶;T3:象草+250 mg·kg-1木聚糖酶+250 mg·kg-1纤维素酶;T4:象草+500 mg·kg-1木聚糖酶;T5:象草+250 mg·kg-1木聚糖酶;C(对照组):象草.切短的象草经酶处理后在25 ℃条件下青贮在发酵瓶内,分别在青贮第2、4、6、8、15和30天从每组取出3瓶青贮样品用于发酵品质测定.结果表明:与对照组相比,纤维素酶与木聚糖酶或两者复合处理均能极显著降低青贮料的pH值(P＜001),增加水溶性碳水化合物(WSC)含量(P＜001)和乳酸(LA)含量(P＜001).青贮30 d结束时,除T3组外,其他酶处理组NH3-N含量显著低于对照组(P＜005);各组中乙酸含量差异均不显著(P＞005).结论:添加纤维素酶或木聚糖酶均能改善象草青贮品质,并以纤维素酶与木聚糖酶复合处理效果最好.     

象草常规营养成分及总能含量分析

对产于昆明东郊的象草春夏秋冬四季样品作常规营养成分和总能含量分析,结果显示：不同季节的样品中各营养成分及总能含量存在一定差异,春季样品粗蛋白11．52％,粗脂肪4．14％,粗纤维27．06％,粗灰分14．23％,无氮浸出物43．05％,总能16719J／g;夏季样品粗蛋白9．76％,粗脂肪3．23％,粗纤维30．07％,粗灰分10．15％,无氮浸出物46．79％。总能16735J／g;秋季样品粗蛋白10．66％,粗脂肪3．08％,粗纤维30．01％,粗灰分10．63％,无氮浸出物45．62％,总能16402J／g;冬季样品粗蛋白7．13％,粗脂肪1．11％,粗纤维40．55％,粗灰分9．04％,无氮浸出物35．44％,总能17238J／g．昆明产象草与重庆产象草相比,各种营养成分含量存在一定差异     

西藏自治区日喀则市白草核型分析

白草（Pennisetum centrasiaticum）广泛分布于世界各地，被牛羊所采食。本试验采用常规根尖压片法对采自西藏日喀则市的白草进行染色体数目统计及核型分析。结果表明：白草染色体总长度为45.87 μm，平均臂比为1.23，核型不对称指数为54.83；所有染色体的臂比在1.08至1.70范围内，其中近中部着丝粒染色体（sm）为1对，其余17对均为中部着丝粒染色体（m），所有染色体未观测到随体出现；白草染色体基数为9，核型为2n=4x=36=34 m+2 sm，属于四倍体植物，核型类型为1A，是进化较原始的物种。     

矮象草补充不同比例米糠和棉粕对生长肥育牛生产性能和经济效益的影响

将20头平均起始体重为223.8±11.5 kg的三元杂交肉牛(本地黄牛×西门塔尔×夏洛来)分成5组进行鲜矮象草Pennisetum purpureum补充不同比例米糠和棉粕的饲养试验,结果表明,不添加补充料组肉牛的平均日增重0.33 kg,极显著低于(P<0.01)其它各组肉牛的平均日增重;当肉牛采食矮象草并每天每千克体重同时补充米糠和棉粕各5 g时,其平均日增重最高,为0.8 kg;每天每千克体重补充米糠和棉粕各2.5 g,肉牛每千克增重成本最低(7.30元),补充料的蛋白质添加量是影响矮象草饲喂价值的主要因素。     

东莞地区能源草种植的探讨

能源草是一种优良的能源植物.通过对东莞地区杂交狼尾草的种植分析,其具有较高的能量转化效率和经济效益,同时具有可观的生态效益,可成为广东地区未来新能源发展的新方向.     

巨菌草与无糠壳高粱白酒糟混合青贮品质及营养成分变化

试验研究巨菌草与不同比例无糠壳高粱白酒糟混合青贮品质及营养成分变化。试验设对照组和3个水平(20%、40%、60%)的无糠壳高粱白酒糟处理组,青贮30 d后分析青贮品质和营养成分。结果表明:各酒糟添加处理组的pH值显著低于对照组(P<0.05),乳酸显著高于对照组(P<0.05)。60%的酒糟处理组的pH值最低,与40%的处理组差异不显著(P>0.05),40%处理组的乳酸含量最高。添加酒糟的各处理组的水溶性碳水化合物含量显著高于对照组(P<0.05)。与青贮前相比,40%的酒糟处理组的干物质、粗蛋白损失相对最少,酸性洗涤纤维和中性洗涤纤维下降比例最多。研究表明,40%的无糠壳高粱白酒糟与巨菌草混合青贮有利于提高青贮发酵品质和营养组分的保存。