Effect of maternal soil treatment on first year growth and autumn frost hardiness of Pinus sylvestris L. full‐sib families

After‐effects of maternal soil treatment, controlling for photoperiod and weather conditions, were tested in a nursery experiment with Pinus sylvestris L. seedlings. Three full‐sib crosses were replicated in 4 different soil treatment plots of a grafted experimental seed orchard (63"54'N). Weight of filled seeds, percentage of empty seeds, first year hypocotyl and epicotyl length, and autumn frost hardiness (from artificial freeze testing) were evaluated. Systematic effects from maternal soil treatment were small compared to family differences for all characters studied. However, epicotyl length of the progenies showed a positive relationship with N needle content of the mother grafts. The results also indicated an important interaction between maternal soil treatment and autumn frost hardiness of the families. It is suggested that the altered mother tree treatment could lead to a change in progeny performance, corresponding to a 1.5 degree difference in latitudinal origin of natural stand seedlings. The results demonstrate the advantages of providing the mother tree with uniform conditions in early progeny testing.     

《中国木本植物种子》

AIM: To test whether ischemic preconditioning (IPC) delays ischemia-induced electrical uncoupling by activation of mitochondrial ATP-sensitive potassium channels (mitoK_ATP). METHODS: Adult rat hearts perfused on a Langendorff apparatus were subjected to 40 min ischemia followed by 30 min reperfusion. Changes in coupling were monitored by measuring whole-tissue resistance. RESULTS: IPC delayed the onset of uncoupling campared to ischemic control; Blocking mitoK_ATP channels before the IPC protocol abolished the delay of uncoupling. The specific mitoK_ATP channel opener diazoxide mimicked the protective effect of IPC. The delay induced by diazoxide was reduced by 5-HD, L-type Ca²⁺ channel inhibitor verapamil and a free radical scavenger N-(2-mercaptopropionyl)glycine. CONCLUSIONS: IPC delays the onset of cellular electrical uncoupling induced by acute ischemia, in which activation of the mitoK_ATP channels may be involved.     

Effects of human urotensin II on ischemia/reperfusion injury in isolated perfused rat hearts

AIM: To investigate the effects of human urotensin II (hUII) on ischemia/reperfusion (I/R) injury in isolated rat hearts. METHODS: In the ischemia/reperfusion (I/R) model of isolated perfused rat hearts, the effects of hUII pretreatment on cardiac function was monitored with cardiac function software of MFL Lab200. ATP, total calcium, and malondialdehyde (MDA) content in myocardium were detected. The coronary perfusion flow (CPF) and lactate dehydrogenase (LDH) activity in coronary effluent were measured during reperfusion. RESULTS: In the hUII pretreated group, the release of LDH from myocardium was lower [(78.3±18.1)U/L] than I/R group [(109.3±23.9) U/L, P< 0.05], with decreased contents of MDA and calcium in myocardium (decreased by 24% and 27%, respectively, P< 0.05) and an increased myocardial ATP content [(3.8±0.4)μmol/g dw vs (2.2±0.4)μmol/g dw, P< 0.05)]. At the same time, hUII pretreatment increased CPF [(5.4±0.7) mL/min vs (3.8±0.8) mL/min in I/R group, P< 0.05], reduced left ventricular end-diastolic pressure (LVEDP) by 20% ( P< 0.05) with increased±d p /d t max [(217±38) kPa/s and (119±18) kPa/s vs (173±29) kPa/s and (82±25) kPa/s in I/R groups, respectively, P< 0.05]. hUII pretreatment also increased natrite/natrate (NO₂^-/NO₃^-) content in coronary effluent [(52.2±12.0)μmol/L vs (32.1±10.2)μmol/L in I/R group, P< 0.05)]. CONCLUSION: hUII pretreatment attenuated I/R injury in isolated perfused rat hearts. The protective mechanism might be associated with NO-mediated coronary vasodilation.     

Nitric oxide opens the second window of protection in ischemic preconditioning via induction of heat shock protein 72

AIM:To examine the inhibition of nitric oxide (NO) synthesis during ischemic preconditioning (IP) on the induction of heat shock protein 72 (HSP72) and infarct size-limiting effect of the second window of protection. METHODS:Rabbits were subjected to 4 cycles of 5 min of coronary artery occlusion separated by 10 min reperfusion, or received a sham operation. During this procedure, N^G-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NO synthase) was injected intravenously 5 min before IP followed by its continuous infusion. Twenty-four hours later, the hearts were rapidly excised for assaying HSP72 expression or were subjected to 30 min coronary artery occlusion followed by 120 min reperfusion and then measured infarct size (IS). RESULTS:Twenty-four hours later, immunoblotting revealed an increase in HSP72 protein levels in the IP group, and this was blocked by L-NAME. IS of the IP rabbits was reduced as compared with the control (29.8%±3.7% vs 50.8%±4.3%, P＜0.01). IS in the IP rabbits was elevtated as a result of L-NAME treatment (46.0%±5.1%). Administration of L-arginine reversed the effects of L-NAME on the induction of HSP72 and IS (33.5%±4.0%). The intravenous administration of S-nitroso-N-acetylpenicillamine (SNAP, a NO donor) increased the induction of HSP72 and reduced IS (31.3%±5.7%, P＜0.01vs control) 24 h later. CONCLUSION:These findings suggest that NO may be involved in the induction of HSP72 and the opening of the second window of protection of IP.     

COX-2抑制剂预处理对大鼠脑缺血再灌注损伤的保护作用

观察选择性环氧合酶-2（COX2）抑制剂帕瑞昔布钠（parecoxib）预处理对大鼠局灶性脑缺血（focalcerebralischemic,FCI）脑保护作用。参照线栓法制备大鼠局灶性大脑中动脉缺血（MCAO）模型,将60只大鼠随机分为假手术组（A组）、局灶性大脑中动脉缺血/再灌注模型组（B组）、帕瑞昔布钠小剂量组（C组）和帕瑞昔布钠大剂量组（D组）。分别采用神经功能缺失评分、TTC染色法、免疫组化和原位杂交检测观察帕瑞昔布钠的脑保护作用,探讨帕瑞昔布钠在脑保护作用中的重要地位。结果,与模型组相比帕瑞昔布钠不同剂量治疗组神经功能缺失明显减轻（P〈0．05）,梗死体积明显缩小（P〈0．05）,凋亡细胞明显减少,帕瑞昔布钠1．6Pag／kg及帕瑞昔布钠3．2mg／kg组COX-2mRNA阳性细胞数与模型组比较显著减少（P〈0．001,P〈0．05）;结果表明,帕瑞昔布钠预处理可减轻脑缺血再灌注损伤,具有一定的脑保护作用。     

干旱预处理对抗旱性不同的2个草地早熟禾品种耐热性能的影响

为探讨干旱预处理诱导草地早熟禾耐热性效应和生理机制及不同品种对干旱预处理的差异响应,对抗旱性不同的2个草地早熟禾品种,“Midnight”(抗)和“Brilliant”(敏感)分别进行充足浇水(对照)和两轮干旱预处理,然后置入35℃/30℃(昼/夜)高温中胁迫25 d。在胁迫的0,5,10,15,20,25 d分别测定草坪外观质量及相应生理反应的动态变化。在胁迫期间,预处理“Brilliant”的草坪质量(TQ)显著(P<0.05)高于未经预处理材料;在胁迫5 d后,经预处理的“Brilliant”渗透势(OP)不断下降,而对照材料基本维持不变,在10和15 d时,预处理Brilliant的相对含水量(RWC)显著(P<0.05)高于对照;在胁迫的10～20 d,经预处理“Brilliant”的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性显著(P<0.05)高于未经预处理材料,而电解质渗透率(EL)值则相反;15 d时,经预处理的棕榈酸(16∶0)和硬脂酸(18∶0)含量显著(P<0.05)低于未经预处理材料,而亚麻酸(18∶3)含量正好相反,与之相对应,预处理“Brilliant”的双键系数(DBI)显著(P<0.05)高于对照。“Midnight”两处理的各测定指标变化趋势相近,无明显差异。结果表明,干旱预处理未能进一步提高抗旱性品种“Midnight”的耐热性,而有效提高了干旱敏感品种“Brilliant”的耐热性。“Brilliant”耐热性的获得与干旱预处理诱导其渗透调节能力的提高,激活抗氧化酶(SOD、CAT)活性从而保护膜脂中不饱和脂肪酸(18∶3)免受活性氧伤害而急剧下降密切相关,从而有效阻止叶片失水,稳定膜结构,延缓植株衰老。     

华北落叶松胚性组织超低温保存技术研究

  目的  超低温保存是植物优良种质长期保存的重要方法。本文为探究梯度预处理对超低温保存存活率的影响,以期有效保存华北落叶松胚性组织的发育潜能。  方法  本研究以华北落叶松胚性组织为材料,对超低温冷冻保存程序中预培养、冷冻处理方式、解冻方式和恢复培养等关键环节开展研究。预培养和冷冻保护共设计成4种处理,以不经过预培养和冷冻保护直接冷冻保存为对照,每个处理重复3次。  结果  结果表明:处理组合1、2、3之间虽无显著差异,但结合冷冻保护剂二甲基亚砜（ DMSO）对细胞具有一定毒害作用,高浓度的DMSO会影响后续胚性组织的恢复甚至造成细胞死亡,因此选出效果较好的超低温保存方法为: 0.2、0.4 mol/L山梨醇液体梯度预处理与0.4 mol/L山梨醇 + 5%DMSO为冷冻保护剂进行冷冻保护,最佳解冻方式为37 ℃水浴,解冻后的胚性愈伤组织细胞活性最高达78%;超低温保存后的胚性组织与正常增殖的胚性组织在外观及显微结构上无明显差异,且低温保存后的愈伤组织仍保持分化形成体细胞胚的能力。  结论  研究结果为华北落叶松乃至其他针叶树胚性组织的超低温保存提供了参考。      

Genetic variation in photoperiodic preconditioning in Pinus sylvestris L. seedlings

Thirty‐two southern Swedish families of Pinus sylvestris L. from a partial 11×11 factorial mating were grown at four night lengths, 3, 5, 7, and 9 h, from the start of their first growth period. At the end of the growth period, the plants were exposed to increasingly longer nights until total growth cessation. During the second and third growth periods, the plants shared the same growing conditions in the growth chambers, starting with two weeks of 6‐h night followed by night prolongation as in the first growth period. The plants from the 9‐h treatment grew more slowly than those from the other treatments in growth periods 2 and 3. The genetic influence of the growing conditions during the first growth period on the height increment during growth periods 2 and 3 was estimated by the female and male by treatment interaction variances. These variance components were relatively small and totally negligible when data from the 9‐h treatment were excluded from the analysis. The data suggest stability in the parents with respect to preconditioning caused by varying photoperiods.