钾肥用量对温室番茄产量及品质的影响

为了探究对春温室番茄产量品质最适宜的钾肥用量(以K_2O计),试验设5个K_2O用量水平,分别是0、9、13.5、18、22.5 kg·667 m~(-2)。通过试验得出,K_2O用量为13.5和18 kg·667 m~(-2)的处理分别在株高和茎粗上变现最优;667 m~2施18 kg的K_2O产量最高,为8 284.73 kg,4个施钾肥处理均与对照呈显著差异,通过回归分析,得出667 m~2施18.52 kg时产量达到最大;品质方面,18 kg·667 m~(-2)的处理在维生素C和可溶性固形物含量上的表现最好,13.5和18 kg·667 m~(-2)的处理在果实硝酸盐含量上均表现较低,与其他3个处理呈显著差异。因此,667 m~2施K_2O在13.5～18.52 kg时,对滴灌条件下春温室番茄的产量提升和品质改善有明显的促进作用。     

不同氮钾用量对设施西瓜产量和品质的影响

以西瓜为试材,通过不同氮钾用量试验,研究了不同肥料用量对西瓜生长发育、产量和品质的影响。结果表明:在一定范围内,随着氮用量的上升,西瓜产量增加。当每667m~2氮用量达到10kg以后,西瓜产量开始呈下降趋势;钾对提升西瓜品质有较大作用,高钾处理(每667m~2施用16kg K_2O)比低钾处理(每667m~2施用14kg K_2O)糖酸比提高4.57%~6.27%。该试验条件下每667m2氮、钾推荐用量分别为6.73kg和16kg。     

钾肥用量和施用时期对苹果产量、品质和果园钾素平衡的影响

为确定苹果生产中钾肥的合理用量和施用时期,在陕西凤翔、山东栖霞、辽宁盖州开展田间试验,研究钾肥用量和施钾时期对苹果产量、品质的影响。结果表明,在陕西凤翔、山东栖霞、辽宁盖州试验点,苹果树密度分别为1 667、889、833株/hm~2的情况下经济最佳钾用量分别为K_2O577、467、1182 kg/hm~2,最高产量施钾量分别为K_2O 582、491、1 190 kg/hm~2。适量施用氯化钾可提高可溶性固形物含量,增加果实硬度,降低果实酸度。钾用量相同下,氯化钾与硫酸钾对苹果产量和品质影响相当。施钾处理果园钾素均有盈余。陕西钾肥适宜的施用时期是50%钾肥花期施,50%钾肥果实膨大期施;山东和辽宁钾肥适宜施用时期是50%钾肥基施,50%钾肥果实膨大期施。果实硬度与K/Ca比呈负相关,施钾有引起果实缺钙风险,因此施钾肥尤其后期施钾应注意补充钙营养。     

有机肥配合减施磷肥对甜椒产量、品质及土壤有效磷含量的影响

为提高蔬菜品质,减少过量的化肥投入,在土壤速效磷含量较高的情况下,通过配合施用有机肥,研究追施磷肥对甜椒产量、品质和土壤速效磷的影响。设4个处理,分别为处理1(T1):底肥不施用有机肥,不追施磷肥;处理2(T2):底肥不施用有机肥,追施磷肥纯量5 kg·667 m~(-2);处理3(T3):底肥施用有机肥2 000 kg·667 m~(-2),不追施磷肥;处理4(T4):底肥施用有机肥2 000 kg·667 m~(-2),追施磷肥纯量5 kg·667 m~(-2)。结果表明,施用有机肥后,不追施磷肥情况下对甜椒的产量和品质没有显著影响。其中,处理4甜椒产量最高,为2 430.75 kg·667 m~(-2),处理1产量最低,为2 019.80 kg·667 m~(-2)。处理3甜椒果实品质优于处理1和处理2,与处理4之间无显著差异,说明施用有机肥后,不追施磷肥对甜椒品质没有明显影响。不施用磷肥能够减少有效磷在土壤中的累积,处理4施肥后土壤有效磷含量最高,为247 mg·kg~(-1),与其他处理相比分别增加40.34%、26.02%、13.30%。     

豫西褐土区施钾对芥菜品质的影响

在豫西褐土区研究了施钾对芥菜品质、硝酸还原酶(NR)、谷丙转氨酶(GPT)等活性的影响。试验结果表明，在速效钾含量为82 mg/kg的供试土壤上施用钾肥，芥菜(块根)的品质性状明显受到影响；施钾量在0~17.5 kg/667 m2时，增施钾肥对芥菜品质的改善效应增强；超过17.5 kg/667 m2时，芥菜品质趋于稳定，进一步增加钾肥对品质的影响作用减小；施钾量增加对荠菜品质的改善，与叶片的NR和GPT活性增强有关。     

氮、磷肥减施对设施嫁接西瓜的影响

为研究化肥减施对嫁接西瓜长势、产量和品质的影响,以西瓜常用施肥量为对照,通过20%~80%的氮肥和磷肥的减施,对‘甬砧3号’嫁接的‘甬蜜2号’进行处理,分析肥料减施对西瓜长势、产量和品质的影响。结果表明,处理间的西瓜单果质量(4.98~6.11 kg)和果形指数(1.02~1.05)差异不显著,长势(主蔓长2.39~2.56 m)和糖度(9.79%~11.21%)差异显著。除边缘糖度外,其余性状均表现为随化肥施用量的增加而增加的趋势,其中减施40%(尿素和过磷酸钙667 m~2施用10.8 kg)和20%(尿素和过磷酸钙667 m~2施用14.4 kg)氮肥和磷肥的综合效果较佳。     

不同施钾量对'骏枣'产量、品质及光合特性的影响

【目的】通过研究钾肥施用量对'骏枣'产量、品质、光合效率和树体营养的影响,以期确定'骏枣'最适宜施钾量。【方法】以'骏枣'为试材,设置钾肥(K_2O)施用量分别为76.5 g·株~(~(-1))、153 g·株~(~(-1))、229.5 g·株~(~(-1))、306 g·株~(~(-1)),于开花期和果实膨大期根际施入。【结果】与对照相比,施钾可显著提高'骏枣'果实产量、维生素C含量、可溶性蛋白质含量、糖酸比、可溶性糖含量、蔗糖含量、果糖含量和叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、叶绿素含量,且具有钾肥浓度影响效应。主成分分析结果表明,4种施钾处理中以施钾(K_2O)153 g·株~(~(-1))对提高'骏枣'果实产量、品质、叶片光合效率和降低果实裂果率的效果最为显著。【结论】施用钾肥能明显提高'骏枣'果实产量、品质和叶片光合效率,增强'骏枣'树体营养状况,降低果实裂果率。因此,在甘肃黄河灌区'骏枣'以高产优质为目标,推荐钾肥(K_2O)施用量为153 g·株~(~(-1))。     

小白菜优化配方施肥初探

以小白菜为材料,研究了不同施肥处理对小白菜产量、硝酸盐含量、硝酸盐还原酶活性及VC含量的影响。试验结果表明,在土壤1中优化配方施肥在氮、磷用量分别比常规施肥减少42%、61.47%,钾增加29.07%的情况下(N 4.35 kg/667 m~2、P_2O_52.89 kg/667m~2、K_2O 9.68 kg/667 m~2),产量增加20.04%,VC含量增加32.52%,硝酸盐含量降低31.56%;土壤2中优化配方施肥在施用氮、磷分别比常规施肥减少100%、100%,钾增加3.8%的情况下(N 0 kg/667 m~2、P_2O_5 0 kg/667 m~2、K_2O 7.79 kg/667 m~2),产量增加49.19%,VC含量增加101.63%,硝酸盐含量降低51.37%。土壤1和土壤2结果比较发现,在不同肥力土壤中,优化配方施肥处理的小白菜都取得了较高的产量、较好的品质,但在不同肥力土壤中最优施肥量不一样,具体施肥量需要根据土壤肥力和作物种类考虑。     

硫酸钾钙镁肥在辣椒上的施用效果

为探明硫酸钾钙镁肥在辣椒上的施用效果,以辣椒品种‘海椒309’为试材,研究了4种施肥水平对辣椒的生长、品质、产量及土壤养分的影响。结果表明,667 m~2施100 kg硫酸钾钙镁肥处理的平均单果质量达59.9 g,显著高于667 m~2施25 kg硫酸钾钙镁肥处理和对照;果径和果肉方面,667 m~2施肥50 kg硫酸钾钙镁肥处理的效果达到最佳,果实纵横径分别为39.90、0.44 mm,分别比对照提高了5.0%和12.8%;在品质方面,667 m~2施75 kg硫酸钾钙镁肥处理的辣椒维生素C和可溶性糖含量达到最大,分别比对照高出7.6%和20.5%;耐贮性方面,采摘后20 d,施用了硫酸钾钙镁肥的所有处理商品果率均显著高于对照,其中商品果率最高的处理是667 m~2施25 kg硫酸钾钙镁肥,为44.73%,比对照高10.12%;提升土壤养分方面,667 m~2施100 kg硫酸钾钙镁肥处理的土壤交互性钙含量(ω,后同)提高最多,达1 851.3 mg·kg~(-1),高出试验前土壤2.4倍,其他处理土壤养分均有不同程度提高;产量方面,667 m~2施100 kg硫酸钾钙镁肥处理的产量最高,达2 382.00 kg,与对照相比增产23.95%。硫酸钾钙镁肥不仅有助于提高辣椒果实单果质量、果长、果肉厚、维生素C含量和可溶性糖含量,而且对于提高辣椒耐贮性和提升土壤养分含量也有一定作用。     

矿物质肥对西瓜产量及品质的影响

为探讨矿物质肥对西瓜产量和品质的影响,以中国农业科院郑州果树研究所培育的西瓜品种‘郑抗巨丰’‘大果黑美人’为试材,根据矿物质肥不同施用量共设置了4个水平0、160、200、240 kg·667 m~(-2)。采用统一栽培管理的方式,比较分析添加不同矿物质肥水平对西瓜可溶性固形物含量等品质和西瓜产量的影响。结果表明,施用矿物质肥可以增加西瓜中心和边部可溶性固形物含量,提高西瓜单瓜质量、667 m~2产量。随着矿物质肥施用量的增加,西瓜中心、边部可溶性固形物含量以及西瓜单瓜质量、667 m~2产量,均成上升趋势,而果皮厚度随添加矿物质肥量增加呈先升高后降低趋势。综合试验结果,添加240 kg·667 m~(-2)矿物质肥对增加西瓜产量、提高西瓜品质的效果最佳。     

Effects of stretch on transient outward potassium and inward rectifier potassium current in cultured neonatal rat atrial myocytes

AIM：To investigate the effects of mechanical stretch on transient outward potassium current (Ito), inward rectifier potassium current (IK1) and action potential duration(APD) of cultured neonatal rat atrial myocytes. METHODS：Neonatal rat atrial myocytes were isolated and cultured on silicone sheeting with or without stretch for 24 h. The silicone membrane area was increased by 12% in stretched group. The cells without stretch served as control. Ito, IK1 and APD were recorded by the technique of whole-cell patch clamp. RESULTS：Compared with control group, Ito density in stretched myocytes was significantly reduced ［(16±04) pA/pF vs (121±29) pA/pF, P<001］, whereas IK1 density was increased ［(-108±08) pA/pF vs (-88±09) pA/pF, P<001］. The APDs at 50% and 90% levels of repolarization (APD50 and APD90) in the stretched cells were obviously decreased than those in non-stretched cells ［(105±14) ms vs (155±24) ms, (300±28) ms vs (563±36) ms, P<001］. CONCLUSION：Stretch stimulation leads to the reduction of Ito density, the increase in IK1 density and the shortness of APD in cultured rat atrial neonatal myocytes, which may contribute to atrial electrical remodeling induced by pressure overload.     

开花期追施氯化钾对西瓜的影响

在西瓜开花坐果期,追施氯化钾15kg/667m2,并及时浇水。结果表明:追施1周后,单株鲜茎叶生长量(3年均值)比不追施(对照)的减少275g,西瓜果个、整齐度、瓜皮亮度等外在商品性状均优于对照;3年平均增产西瓜447.8kg/667m2,增幅为37.7%。     

Cannabinoid-induced peripheral analgesia depends on activation of potassium channel

AIM:To observe the dynamic expression of cannabinoid receptor type 1 (CB1 receptor) in peri-pheral injured area during pain and to explore whether activation of CB1 receptor is regulated by potassium channel. METHODS:A mouse model of chronic constriction injury (CCI) was established to observe the changes of pain behavior by von Frey and Hargreaves tests. Western blot was used to detect the dynamic changes of CB1 receptor. The discharge frequency of sciatic nerve single fiber was recorded to investigate whether CB1 receptor activation was regulated by potassium channel. RESULTS:With the decrease in the pain threshold, the expression of CB1 receptor in the area of sciatic nerve injury was increased, and injection of CB1 receptor agonist HU210 in the area of peripheral injury had a significant analgesic effect. However, after injection of CB1 receptor antagonist AM281 or potassium channel non-specific blocker tetraethylammonium (TEA) for 20 min, the analgesic effect of the HU210 injection disappeared. The perfusion of HU210 in the injured area significantly reduced the spontaneous ectopic discharge frequency of the injured nerve fibers, but the early perfusion of AM281 or TEA suppressed this effect. CONCLUSION:The analgesic effect of CB1 receptor is mediated by potassium channel.     

Nutrition of glasshouse strawberries with nitrogen,phosphorus and potassium

A study was made of the fertilisation of glasshouse soil and nursery beds in the open for strawberries. The response of the crop to variations in fertiliser treatment was greater in the nursery beds than in the glasshouse. Only nitrogen dressing were of some importance under glass, but too much nitrogen proved to be harmful. The correct fertilisation of the nursery beds with nitrogen and potash is most important. Basic slag proved to be a suitable phosphate fertiliser for the nursery beds, but triple superphosphate cannot be recommended.     

Effects of piperine on abnormalities of inward rectifier potassium current and ultra rapid delayed rectifier potassium current induced by hydrogen peroxide in rabbit atrial myocytes

AIM: To study the protective effect of piperine on abnormalityies of inward rectifier potassium current (I_K1) and ultra rapid delayed rectifier potassium current (I_KUr) induced by hydrogen peroxide (H₂O₂) in single rabbit atrial myocytes. METHODS: The technique of whole-cell patch-clamp was used to study the effect of H₂O₂ at concentration of 50 μmol/L on I_K1 and I_KUr in single rabbit atrial myocytes. The protective effect of pretreatment with piperine (7 μmol/L) was also observed. RESULTS: The piperine at concentration of 7 μmol/L had no significant effect on I_K1 and I_KUr and their channel dynamics. In the presence of H₂O₂ at concentration of 50 μmol/L, the peak currents of I_K1 and I_KUr reduced significantly (P<0.05).The steady-state activation curve of I_KUr was shifted right, the steady-state inactivation curve of I_KUr was shifted left, and the recovery from inactivation of I_KUr was shifted downward. The I_KUr showed frequency-dependent characteristics. Piperine at concentration of 7 μmol/L significantly alleviated the inhibitory effect of H₂O₂ on I_K1 and I_KUr (P<0.01). In addition, piperine protected against the changes of I_KUr dynamics induced by H₂O₂. CONCLUSION: Piperine alleviates the abnormalities of I_K1 and I_KUr induced by oxidative stress in atrial myocytes.     

Changes of potassium currents in rabbit ventricle with healed myocardial infarction

AIM: To elucidate the mechanism of arrhythmia in healed myocardial infarction (HMI), and to investigate the changes of action potential duration (APD),transient outward potassium current (I_to), delayed rectifier potassium current (I_K) and inward rectifier potassium current (I_K1) of left ventricular myocytes in noninfarcted zone of HMI. METHODS: 12 rabbits were randomly assigned in two groups: HMI group (thoracotomy and ligation of the circumflex coronary); sham-operated group (thoracotomy but no conorary ligation). 3 months after operation, whole cell patch clamp technique was used to record APD, I_to, I_K and I_K1 of ventricular myocytes in non-infarcted zone. RESULTS: Membrane capacitance was larger in HMI group than that in sham-operated group. Action potential duration was lengthened significantly in HMI group and early after depolarization (EAD) appeared in HMI group. The densities of I_to, I_K,tail and I_K1 were reduced significantly in HMI group (P<0.01), from (6.72±0.42) pA/pF, (1.54±0.13) pA/pF and (25.6±2.6) pA/pF in Sham-operated group to (4.03±0.33) pA/pF, (1.14±0.11) pA/pF and (17.6±2.3) pA/pF, respectively. CONCLUSION: The reduced densities of I_to, I_K,tail and I_K1 in ventricular myocytes of non-infarcted zone in HMI are responsible for the prolongation of APD and the presentation of EAD, which play important roles in the malignant arrhythmia of HMI.     

钾对猕猴桃果实品质与贮藏的影响

为提高猕猴桃果实品质与耐贮性,以7年生美味猕猴桃品种米良1号(Actinidiadeliciosacv.Miliang-1)为试材,进行果实生长发育期施钾处理对果实品质与贮藏性能影响的研究。结果表明:适量施钾能提高果实硬度及可溶性固形物与维生素C含量,降低果实含酸量,提高果实耐贮性。在0-4℃贮藏条件下,以株施纯K2O80g+叶面喷施0.3%硫酸钾处理果实贮藏效果最佳,贮藏73d时,其软果率最低(15.56%),果肉硬度最高(0.27MPa)。同时果实维生素C含量的下降趋势较为平缓,果实贮藏寿命延长。贮藏6个月时,株施纯K2O80g+叶面喷施0.3%硫酸钾处理的果实好果率(68.89%)明显高于对照果实(0)。     

Estrogen affects reactivity of rat mesenteric artery through ATP-sensitive potassium channel

AIM: To observe the expression of ATP-sensitive potassium (K_ATP) channel mRNA in mesenteric artery smooth muscle of rats with estrogen administration, and to evaluate the role of K_ATP channel in the effects of estrogen on the reactivity of mesenteric artery in rats. METHODS: Forty-eight female Sprague-Dawley rats, weighing (100?10) g, were randomly divided into 3 groups: sham operation (sham) group, ovariectomy (Ovx) group and ovariectomy with estrogen administration (Ovx+E) group. The mRNA expression of K_ATP subunits in mesenteric artery smooth muscle was detected by quantitative real-time PCR. Artery reactivity in the rats was observed by norepinephrine-induced pressor response. RESULTS: Compared with sham group, the mRNA expression of Kir6.1 and SUR2B was significantly decreased in Ovx group (P<0.05), but increased in Ovx+E group (P<0.05). Compared with sham group and Ovx+E group, the pressor response induced by norepinephrine in the rats were enhanced in Ovx group (P<0.05). No significant difference between sham group and Ovx+E group was observed. After administered with glibenclamide (a K_ATP channel blocker), the pressor response induced by norepinephrine was enhanced in sham group and Ovx +E group, and no changes in Ovx group. Meanwhile, no difference among the 3 groups was found. CONCLUSION: Estrogen up-regulates the expression of K_ATP channel subunits, which may be involved in estrogen-reduced pressor response to norepinephrine.