60Co-γ射线辐照诱变尖端菌丝选育猴头菌多糖高产菌株

采用^60Co-γ射线辐照诱变尖端菌丝，在辐照剂量为800Gy和剂量率为27、84Gy／min的条件下选育出一株猴头菌多糖高产菌株。其拮抗试验和过氧化物酶同工酶试验均证明其为变异株。经液体培养其生物量和原始菌株相比提高14、2％，菌丝多糖产量提高2倍。经6次传代培养后，其生物量和菌丝多糖产量较稳定，且明显超过原始菌株，表明其遗传稳定性良好。     

姬松茸60Co-γ射线辐照诱变育种试验初报

采用60Co-γ射线辐照诱变尖端菌丝,在辐照剂量为800Gy,剂量率8.3Gy·min-1的条件下,通过菌丝生长速度、拮抗试验、品比栽培试验选育出一株姬松茸优良菌株JB-6.新菌株在菌丝生长速度、出菇期及产量等方面,均优于对照菌株.     

60Co-γ射线辐照对花椒的诱变效应

以莱芜"大红袍"花椒为试材,利用不同剂量~(60)Co-γ射线(0、50、100、150、200、250、300Gy)辐照处理休眠态和萌芽态花椒种子,测定出苗率、初生苗高度、节间长度、节间数、叶型及株型等生理指标。结果表明:~(60)Co-γ射线辐照剂量与休眠态和萌芽态种子的出苗率呈极显著负相关,与致死率呈极显著正相关,休眠态种子的最适辐照剂量为100Gy,萌芽态种子的最适辐照剂量为50Gy。萌芽态种子实生苗的株高和节间数随辐照剂量增加先降后升,休眠态种子随剂量增加而不断下降,其中50Gy辐照后的萌芽态种子的苗高和节间数与100Gy辐照后的休眠态种子的苗高和节间数基本相同。突变体主要为株型异形和叶型异形,休眠态种子实生苗的变异率受辐照剂量的影响显著,辐照剂量为150Gy时,其变异率接近100.0%。由此表明,休眠态种子对高剂量~(60)Co-γ射线辐照更敏感,萌芽态种子对辐照损伤的自我修复能力更强。研究结果将为花椒稳定突变体的获得和花椒新种质的获得奠定良好的基础。     

60Co诱变方法选育高产多糖槐耳菌株

采用槐耳T菌株作为诱变材料,进行60Co射线的诱变试验（剂量为1000Gy,剂量率为10Gy·min^-1）,筛选出多糖含量高且适合栽培的新菌株T189,其多糖产量为37．13％,比槐耳T菌株（27．48％）提高35．1％。     

~(60)Co-γ射线对辣椒种子的辐照效应

分别采用剂量为50、100、150、200、300、400、500 Gy(2015年)和200、300、400、500 Gy(2016年)的~(60)Co-γ射线对辣椒种子进行辐照,并研究其对辣椒种子发芽动态、成苗率及辣椒幼苗形态指标的影响。结果表明:高辐照剂量可显著抑制辣椒种子的发芽指数、成苗率,降低辣椒幼苗的茎高、茎粗、主根长度、叶长和叶宽,但对辣椒种子的发芽率影响不大。不同品种间辐照剂量效应不完全相同,经过二次曲线拟合确定,湄潭团籽辐照适宜剂量为450 Gy,罗甸朝天椒辐照适宜剂量为350 Gy。     

冷藏与辐照对山药保鲜效果的比较研究

以铁棍山药为试材,研究冷藏与不同剂量γ射线辐照后常温贮藏期间山药的发芽及重量损失情况,并分析了不同处理样品的感官指标和可溶性总糖、粗蛋白、水分及灰分含量。结果表明:冷藏和70~100 Gy剂量辐照均可有效地抑制山药的发芽、减少重量损失率,100 Gy处理贮藏期间的重量损失比70 Gy显著减小,且贮藏期越长,冷藏和辐射处理减少山药重量损失的效果越显著;冷藏和辐照保鲜90 d的山药品质优良,冷藏的保鲜效果优于辐照。     

60Co-γ辐照对火龙果种子萌芽生长的影响

为探明60Co-γ射线辐照对不同品种火龙果种子的辐射效应,以"蜜红""蜜宝""翠蜜""金都一号""富贵红""大红""燕窝果"7个品种火龙果新鲜种子为材料,分别经0、25、50、100、200、300、400、500 Gy剂量60Co-γ射线辐照处理,比较不同处理对火龙果种子萌发、根长及出苗的影响。结果表明,不同剂量60Co-γ射线辐照对火龙果种子的萌发和生长均有不同程度的影响,辐照剂量为25~100 Gy时60Co-γ射线可以促进种子萌发和生长。随着剂量的增大,辐照对于种子的萌发率、出苗率和根长抑制明显,剂量与之呈负相关。100 Gy处理的种子萌发率和出苗率最高,200~500 Gy时种子萌芽生长受抑制;200 Gy处理的出苗率均极显著比对照低。     

低剂量60Co-γ辐照刺激拟南芥植株生长的效应

以拟南芥为试材,以0、50、150Gy剂量~(60)Co-γ辐照拟南芥种子,研究其对拟南芥植株生长发育的影响。结果表明:与对照相比,50Gy辐照处理显著增加了拟南芥植株高度、莲座叶长度、角果长度、种子数量以及叶片光合色素含量;150Gy辐照拟南芥的各项生长和生理指标显著降低,表明高剂量辐照处理抑制了拟南芥植株的生长。说明低剂量的~(60)Co-γ辐照显著促进拟南芥植株的营养生长和生殖生长。     

平菇菌株栽培比较试验

平菇出菇管理简单，产量高，价格适中，消费量大，栽培户逐年增多。为选出适宜本地栽培的平菇菌株，我们做了15个平菇菌株栽培试验，为菇农选择栽培菌株提供依据。现将试验报告如下。     

60Co-γ射线辐照对菜用枸杞VM2生长氏及品质的影响

用10～14Gy~(60)Co-γ射线辐照菜用枸杞农枸1号枝条,研究低剂量辐照对无性繁殖二代(VM2)生长与品质的影响。结果表明:10、11Gy辐照促进菜用枸杞VM2的生长,其中经10Gy辐照的促进效果最好,其株高、叶长和叶宽显著高于对照V2,13、14Gy辐照对VM2生长有一定抑制作用;辐照对菜用枸杞VM2嫩茎叶的VC、可溶性糖和氨基酸含量均有较大影响,其中10、11Gy辐照显著增加了VC、可溶性糖和氨基酸含量;经模糊数学隶属函数法综合分析评价,10Gy辐照处理的VM综合品质最优。     

辐照花粉授粉及胚挽救时期对苦瓜离体雌核发育的影响

采用辐照花粉授粉结合胚挽救技术,以7个不同基因型苦瓜作花粉供体对MC52进行授粉,系统探讨辐照剂量、胚挽救时期对成苗率的影响及辐照剂量对产胚类型的影响.结果表明:进行苦瓜辐照花粉授粉诱导离体雌核发育的适合辐照剂量为150 Gy,胚最佳抢救时期为授粉后第10天.试验发现辐照剂量在200Gy时也可获得高的坐果率,但大部分种子已成空壳,对于苦瓜辐照花粉授粉诱导雌核发育获得单倍体是没有意义的；对辐照获得的102株苗进行倍性鉴定,虽未得到单倍体植株,但在该试验中仍有较高比例的各种类型胚未发育成植株,还须进一步优化胚的培养条件.     

~(60)Coγ辐射对不同品种草莓离体叶片再生及芽生长的影响

以丰香和章姬草莓的无根无菌苗为试材,用10～40Gy 60Coγ射线辐照处理,以未辐照为对照,研究了60Coγ射线辐射对草莓叶片再生及植株继代增殖的影响。结果表明,叶片对辐射敏感,且丰香叶片比章姬叶片敏感,叶片再生的半致死剂量为10～20Gy;辐照后不同时间取叶接种,丰香叶片的不定芽再生率在剂量10Gy呈上升趋势,而其他剂量则几乎未见有变化,章姬在剂量10～30Gy,叶片的不定芽再生率提高较大,40Gy仍表现轻微下降;适宜的辐射剂量对草莓试管苗增殖有促进作用。     

Effects of radiation from 188Re on smooth muscle cell proliferation

AIM: Although endovascular radiotherapy inhibits neointimal hyperplasia, the exact alterations induced by β-particles irradiation remain to be elucidated. The objective of this study was to investigate the ability and the cellular mechanism of local β^-particles emission from ¹⁸⁸Re to inhibit vascular smooth muscle cells (SMCs). METHODS: The SMCs in vitro were irradiated by ¹⁸⁸Re with single doses of 2.6 Gy-25.8 Gy. The effects of β-particles on SMCs, such as effective irradiate doses, the period of inhibition for SMCs proliferation, the changes of cell proliferation rate and DNA synthesis rate, cell cycle progression and related gene expression, were investigated by cell count, [³H]-TdR incorporation, cell cycle progression analysis, cell viability and immunocytochemistry, respectivecy. RESULTS: β-particles irradiation with dose of 5.2 Gy could inhibit significantly SMCs proliferation. At dose of 20.6 Gy DNA synthesis inhibitory rate was 92%, SMCs proliferation rate was only 3%. Renoval of ¹⁸⁸Re did not abolish the inhibitory effects of β-particles on SMCs proliferation. The expression of P53 was up regulation and PCNA was down regulation after irradiation. CONCLUSION: β-particles from ¹⁸⁸ Re was significantly effective and permanent in inhibiting SMCs proliferation, and inhibitory effect was in dose-dependet manner ED50was 5 Gy, the best dose to inhibit SMCs proliferation was 20 Gy. β-particles irradiation induced SMCs to occur G₀/G₁ arrest, damaged the ability of SMCs reproliferation and led to cell clonogenic death. P53 and PCNA had regulatiory effects on SMCs proliferation after β-particles irradiation.     

Apoptosis and expression of P53 mRNA and protein in mouse spermatogenic cells induced by low dose ionizing radiation

AIM:The effect of low dose radiation (LDR) with different doses of X-rays on apoptosis and its related gene P53 expression were studied in spermatogenic cells of male Kunming mouse testis. METHODS:The different kinds of spermatogenic cells were separated using density gradient centrifugation and their apoptosis was measured by flow cytometry. At meantime, P53 protein and P53 mRNA was measured with immunohistochemical SABC and in situ hybridization, respectively. RESULTS:The apoptosis in all kinds of spermatogenic cells induced by LDR had a remarkable regularity. When the doses were 0.025 and 0.05 Gy, spermatogone apoptosis was domaint. With the increase in irradiation dose (0.075-0.2 Gy), spermatocytes also showed an apoptotic change, but the apoptotic percentage of spermatogonia was significantly higher than that of spermatocytes. Moreover, the apoptosis of spermatids and spermatozoa scarely occurred after LDR. P53 protein expressed in spermatogonia and spermatocytes in varying degrees, and the former was significantly higher than that of the latter after LDR. With the increase in irradiation dose, P53 protein expression showed a upregulated tendency, but that of spermatids and spermatozoa scarcely occurred. P53 mRNA primarily expressed in spermatids and spermatocytes when the dose was 0.025 Gy. With the increase in irradiation doses (0.05-0.2 Gy), that of spermatogonia also showed an enhancement. P53 mRNA expression in spermatogonia and spermatocytes showed a remarkable dose-effect relationship. CONCLUSION:The apoptosis of spermatogenic cells was selectively induced by LDR of X-rays, which had remarkable the dose-effect and time-effect relationships. The mechanism of the selective apoptosis in spermatogenic cells by LDR is closely related to the upregulation of P53.     

Ray florets color and shape mutants induced by C ion beam irradiation in chrysanthemum

Ion beam irradiation is attracting attention in floriculture as a means of inducing mutations. We investigated the effect of ion beam irradiation on induction of ray florets color/shape mutants from two strains of chrysanthemum to create new flower cultivars. The ray florets and leaf explants of chrysanthemum cultivars, ‘Shiroyamate’ and ‘H13’, respectively, cultured on MS medium were irradiated with ¹²C⁵⁺ ion beam at doses of 1, 2, 4 and 8Gy. The frequency of shoot primordia formation on ray florets explants of ‘Shiroyamate’ and shoot bud formation on leaf explants of ‘H13’ was decreased by 8Gy and 4Gy irradiation, respectively. The effective dose of ion beam was less than 4Gy in ‘Shiroyamate’ and less than 2Gy in ‘H13’. After exposure to an effective dose of ion beam, regenerated plants were grown in a green-house and the field. Yellow ray florets mutants from ‘Shiroyamate’, and various ray florets color mutants (dark-red, light red, pink, pink spray) and a flower shape mutant (double-ray florets) from ‘H13’ were induced by ion beam irradiation. Furthermore, a white mutant was obtained from a chimeric mutant. These results suggest that the combination of ion beam irradiation and tissue culture would be an effective means of generation mutants at a high efficiency.     

Effect of Single and Recurrent Gamma Irradiation on in vitro Shoot Cultures of Banana

ABSTRACT

Multiple shoot cultures of three banana cultivars belonging to AAA and AAB genomic groups (Basari, Chakkarakela and Rasthali) were irradiated with gamma rays. The percentage of individual shoot survival declined with increase in irradiation dose indicating an inverse relationship between the two parameters. Lethal dose of 50% was found to be 30Gy. Lower doses (10, 20Gy) enhanced shoot multiplication ratio, which however decreased with increased dosage. AAB cultivars appeared to be more sensitive as compared to AAA cultivars. The multiple shoots were also subjected to recurrent mutagenesis at an interval of 15 days. The percent (%) survival was found to decrease after each irradiation treatment, whereas multiplication ratio was found to be enhanced after third irradiation in Basrai. Individual shoots derived after different irradiation experiments were rooted and the plantlets were hardened in the green house. Among these, few showed morphological variations such as thick shiny dark green colored leaves, ovate leaves and a dwarf with a rosette of leaves in AAB cultivar, Rasthali. This is the first report on the effect of recurrent gamma irradiation on in vitro shoot cultures of banana.     

辐射花粉授粉诱导甜瓜单倍体

为了掌握辐射花粉授粉诱导甜瓜单倍体技术,以5种基因型甜瓜为材料,通过应用γ射线辐射的花粉进行授粉结合胚胎培养,从2种基因型中获得了单倍体植株,单倍体的平均诱导频率为0.29%。这2种基因型分别属于厚皮和薄皮甜瓜类型。花粉的辐射剂量为300Gy和600Gy时,供试材料的平均坐果率分别为50%和10%。辐射剂量为300Gy时,诱导厚皮甜瓜4810和薄皮甜瓜新富玉形成了单倍体植株,单倍体植株的诱导频率分别为0.55%和0.63%;剂量为600Gy时未能诱导供试材料形成单倍体。研究结果表明母本的基因型和花粉的辐射剂量对坐果率和单倍体的产生有一定的影响。此外,对单倍体植株与正常二倍体植株的形态学进行了比较观察,结果表明单倍体植株生长势弱,叶片较小,雄花和雌花均败育。     

60Co-γ射线对李花粉辐射效应的研究

以‘新世纪’、‘石原早生’、‘澳李14’李品种为试材,研究⁶⁰Co-γ辐射,对李花粉发芽率的影响。结果表明:不同剂量率对李花粉发芽率影响较明显,‘新世纪’李、‘澳李14’李均以剂量率0.6 Gy/min辐射后花粉发芽率最高,且随剂量率的升高花粉发芽率逐渐降低;‘石原早生’李以1.2 Gy/min最高。不同剂量对不同李品种花粉发芽率影响相同,‘新世纪’李、‘石原早生’李、‘澳李14’均以剂量20 Gy辐射后花粉发芽率最高,且随剂量的升高花粉发芽率逐渐降低。说明低剂量、低剂量率辐射不同李品种花粉后发芽率较高,可用于远缘杂交育种。     

Evaluation of the sensitivity to ionising γ-radiation of a Cymbidium hybrid

Gamma-rays are an important mutagenic agent that can induce new, useful genetic variations in plants. However, γ-irradiation can also cause damage that negatively affects the use of such mutagens in plant breeding. The aim of the present study was to investigate the effects and damage caused by γ-radiation in a Cymbidium hybrid, RB001. The relative growth rate of protocorm-like bodies (PLBs) was reduced by 50% at a γ-ray dose of approximately 40 Gy. Malondialdehyde concentrations increased significantly with increasing radiation dose. However, almost no difference was observed between untreated control PLBs and PLBs treated with 200 Gy 8 weeks after γ-irradiation. The activities of several antioxidant defence enzymes increased gradually with increasing γ-ray dose, 24 h after irradiation. These enzymes showed different responses between 1 and 4 weeks, but no difference 8 weeks after irradiation. The ‘comet assay’ and flow cytometry were performed. Clear differences in radiation-induced damage were observed between control and 200 Gy-treated PLBs at 24 h. However, PLBs had a tendency to recover from 4 weeks after irradiation, and the integrity of their DNA was similar in samples treated with 10–200 Gy. These results indicated that γ-rays caused little DNA damage and the plants could recover. This demonstrated the feasibility of using physiological responses, the ‘comet assay’, and flow cytometry to detect DNA damage after γ-irradiation.