不同浓度NAA/6BA配比对不同品种甘薯茎尖培养特性的影响

为明确不同品种甘薯茎尖培养的最佳NAA/6BA配比,设置0.1 mg/L/2.5 mg/L、0.2 mg/L/2.5 mg/L、0.2 mg/L/1.0 mg/L 3组NAA/6BA浓度配比处理,观测不同浓度激素处理对‘北京553’、‘红香蕉’、‘苏薯8号’、‘烟薯25’、‘安吉芋’、‘济徐23’、‘渝紫7号’、‘商薯19’茎尖培养成苗率、愈伤组织直径、不定根数目、叶片数和植株高度的影响,同时调查不同品种试管苗的移栽成活率。结果表明,‘红香蕉’、‘济徐23’、‘渝紫7号’、‘商薯19’在0.1 mg/L/2.5 mg/L的处理下培养效率最高;‘安吉芋’在0.2 mg/L/2.5 mg/L的处理下培养效率最高;‘苏薯8号’、‘北京553’、‘烟薯25’在0.2 mg/L/1.0 mg/L的处理下培养效率最高。因此,在甘薯茎尖培养过程中,不同甘薯品种适宜的NAA/6BA配比存在显著差异,在实际生产中应根据品种特性来进行调整激素的用量和比例。     

Unravelling the relationship between a seasonal environment and the dynamics of forage growth in grazed swards

It is well reported in the scientific literature that pastures can have similar net forage accumulation when managed with contrasting structures. However, we hypothesized that the dynamics of forage accumulation in grazed swards is linked to seasonal-environmental conditions. Marandu palisadegrass (Brachiaria brizantha [Hochst. ex A. Rich.] was used as the forage species model. The experimental treatments were four grazing heights (10, 20, 30 and 40 cm) allocated to experimental units according to a randomized complete block design with four replicates and evaluated throughout four contrasting environmental seasons (summer, autumn, winter–early spring and late spring). Under rainy and warm periods, greater net forage accumulation was observed in pastures maintained taller; on the contrary, during the mild and dry periods, net forage accumulation rate reduced as grazing height increased. Such patterns of responses were related to compensations between tiller population density and tissues flows during summer and late spring and the reduced capacity of taller canopies to compensate lower population with greater growth rates during autumn and winter–early spring. Grazed swards changed their patterns of forage growth as they transitioned from favourable to more abiotic stressful conditions, suggesting that seasonal adjustments in grazing intensities are necessary in order to maximize forage production.     

Factors involved in Agrobacterium tumefaciens-mediated gene transfer into Pinus nigra Arn. ssp. salzmannii (Dunal) Franco

Cotyledons from dissected sterile embryos of salgareño pine (Pinus nigra Arn. ssp. salzmannii (Dunal) Franco) were inoculated with different disarmed Agrobacterium tumefaciens strains harbouring the binary vector p35SGUSint. The transient expression of a β-glucuronidase gene (uidA) was studied, using a histochemical staining procedure. Nineteen days after inoculation, the activity of β-glucuronidase was detected in epidermal and subepidermal layers of cotyledonary explants. The EHA105 strain harbouring a disarmed agropine-type Ti-plasmid (pTiBO542) was the most effective for gene transfer of the uidA gene. The effects of exudates and extracts from 0-day-old embryos on induction of vir gene expression in A. tumefaciens were also examined. The results of this study showed that salgarño pine embryo exudates contain a substance(s) that induce vir gene expression, in similar way to that observed with 100 μM acetosyringone (AS).All these findings suggest that T-DNA processing and transfer might take place when Agrobacterium infects suitable tissues of salgareño pine.     

植物非组培遗传转化方法研究的进展

在许多植物中,转化效率低一直是制约分子育种和基因功能研究的障碍。目前,在拟南芥等模式植物的研究中,非组培方法已成为遗传转化的主要手段,这些方法在其它植物中也有广阔的应用前景。本文介绍了几种较为成功的非组培遗传转化方法的应用情况和技术原理,并对下一步研究工作提出了建议。     

魔芋组织培养与植株再生的研究

魔芋幼芽和幼嫩芽鞘,经0.1%升汞灭菌20分钟后,接种在附加BA.NA(均为0.6m/1)的MS培养基上,在室温25土1℃,每天照光9小时的条件下培养三周,形成愈伤组织。愈伤组织转入附加4(mg/1)BA、0.25(mg/1)IBA,3(mg/1)GA_3的MS分化培养基上,四周后分化出芽和白色地下茎,其分化颖率为40%,再转移至附加2(mg/1)BA、1(mg/1)IBA、0.3%活性炭的MS培养基中,幼茎和叶片从芽鞘中抽出,茎基部分化出根,形成完整的小植株。     

龙牙楤木组织培养与快速繁殖技术研究

对龙牙木匆心 木 [Araliaelata (Miq)Seen]的叶片、叶柄和幼茎进行组织培养 ,结果表明 :用叶片进行组织培养的效果最好 ,愈伤组织最高诱导率达 3 7.1%;最适诱导培养基为MS +6-BA 1.0mg/L +2 ,4-D 1.0mg/L ;最适分化培养基为MS +6-BA 2 .0mg/L +2 ,4-D 1.0mg/L ;最好的继代增殖材料为幼根。试验还发现 :用 40 μg/L的硫酸链霉素可以有效防止细菌的污染 ;5g/L的活性炭防止褐变效果最好 ;把握好琼脂的用量及适当降低 6-BA的含量可以降低玻璃化现象的发生频率。     

紫花苜蓿的愈伤组织诱导及组织培养

紫花苜蓿以其品质优良、易于栽培的特点,在饲料牧草中占有重要地位。本实验对苜蓿子叶、下胚轴的愈伤组织诱导进行了研究。结果表明,MS+2,4 D(2mg/L)、MS+6 BA(2mg/L)、1/2MS+NAA(0 5mg/L)分别是紫花苜蓿的愈伤组织、芽、根的适宜诱导培养基。     

库拉索芦荟的组织培养和快速繁殖

以库拉索芦荟（Aloe veraL)茎段为外植体，MS培养基配以不同浓度的IBA，NAA和6-BA进行离体组织培养，结果表明，以MS 6-BA4mg/L NAA0.2mg/L培养基对芽的诱导效果最佳，芽的诱导分化率最高，且试管苗健壮，整齐；增殖培养基以MS 6-BA3mg/L NAA0.2mg/L效果最佳，既有利于芽苗增殖，又有利于芽苗长高；生根培养基用1/2MS NAA0.5mg/L效果最好，可在2周内长根。     

箭胡毛杨组培繁殖技术的研究

采用箭胡毛杨幼叶作为外植体进行组织培养,以MS为基本培养基获得了再生植株。从IAA与6-BA间进行的9个正交试验中,选择出适宜脱分化培养基MS+6-BA 0.5 mg/L+IAA 0.1 mg/L,对箭胡毛杨愈伤组织诱导率为90 %;种生长素与6-BA 配比的再分化培养基中,1/2 MS +IAA 0.1 mg/L+6-BA 0.1 mg/L对不定芽的分化诱导率可达到67.1 %;MS+6-BA 0.5 mg/L+NAA 0.01 mg/L的培养基可使单芽直接增殖出5.6个芽。在MS+IAA 0.8 mg/L的生根培养基上,试管苗的生根率可达82.6 %。     

四倍体刺槐组织培养中的外植体选择和消毒研究

以四倍体刺槐2个无性系为材料,研究了四倍体刺槐不同外植体与不同消毒方法对离体组织培养的影响.试验结果表明:室内水培枝和室外枝条的中下部均可作为离体培养的良好材料,外植体最佳长度为1.0～2.0 cm;用70酒精30 s后,以0.1HgCl2消毒8～10 min,消毒效果最好.