施氮量对超高产冬小麦灌浆期旗叶光响应曲线的影响

为冬小麦超高产栽培的氮肥管理提供技术支撑,在大田条件下研究了施氮量对超高产冬小麦灌浆期旗叶光响应曲线的影响。采用开放式气路测定了小麦旗叶的净光合速率、气孔导度、胞间二氧化碳浓度、蒸腾速率等相关指标,并运用"米式方程"对旗叶净光合速率进行了模拟,计算了光响应曲线的特征参数。结果表明,在0～300kg/hm2施氮范围内,随着光照强度的增加,各处理的旗叶净光合速率、气孔导度、蒸腾速率均随之增加,而胞间二氧化碳浓度却随之降低,但是在375kg/hm2施氮水平下旗叶的净光合速率、气孔导度、蒸腾速率的增加和胞间二氧化碳浓度的降低反而低于300kg/hm2施氮水平,表明合理的氮素水平对超高产小麦灌浆期旗叶的光响应曲线有明显的调节作用。在合理的施氮范围内,增施氮肥小麦旗叶在整个灌浆期内的最大净光合速率随之增加。在本试验条件下,超高产麦田的适宜施氮量为300kg/hm2。

两种种植体系下地下水硝态氮含量变化

寿光作为全国闻名的保护地蔬菜产区,过量施肥的现象非常普遍。为了解集约化大棚蔬菜种植区地下水中硝酸盐的含量变化状况,于2003～2005年对寿光市大田(小麦-玉米)、大棚(一年两茬番茄)两种不同的种植体系下农田灌溉水和农村饮用水水井进行了定点跟踪监测。结果表明:大田区地下水中硝态氮的含量随着时间的变化波动很小,农村饮用水中硝态氮含量没有超标现象;随着时间推移,大棚区灌溉水井中硝态氮含量年内(从年初到年末)呈明显的上升趋势,年际间则存在有规律的波动并逐年升高;灌溉水中硝态氮平均含量普遍高于饮用水,浅层地下水明显高于深层地下水;无论大棚区还是大田区,井深不同对地下水的硝态氮含量影响差异很大,浅井中硝态氮的含量明显高于深井。大棚区农村饮用水硝态氮含量超标现象非常普遍,对国家饮用水标准(20mg·L-1)超标率最高达37.50%,平均为14.06%;对WHO推荐饮用水上限(10mg·L-1)超标率最高达56.25%,平均为42.19%,硝态氮最高含量45.60mg·L-1。集约化大棚蔬菜栽培模式已经对农村地下水造成了很大的硝态氮污染,饮用水中较高的硝酸盐含量已经对当地居民的健康构成了潜在的威胁。

施氮量和花后土壤含水量对优质强筋小麦产量和品质的影响

在防雨池栽条件下,研究了施氮量和花后土壤含水量对优质强筋小麦产量和品质的影响。结果表明,在同一施氮量条件下,表现为花后土壤含水量过高（80%～90%）或过低（40%～50%）导致穗粒数减少,千粒重降低,最终使产量降低。在同一土壤含水量下,表现为增加施氮量有利于提高穗数,但过多（300kg/hm^2）或过少（150kg/hm^2）施氮均不利于穗粒数和千粒重的提高,而导致减产。在同一土壤含水量下,总蛋白质、醇溶蛋白、麦谷蛋白含量及谷/醇比随着施氮量的增加而增加。在同一施氮量条件下,总蛋白质及各组分均随着土壤含水量的增加而降低,同时谷/醇比也降低。在同一施氮量下,花后土壤含水量过高（80%～90%）或过低（40%～50%）均不利于淀粉及其组分含量的提高。在同一土壤含水量下,过高（300kg/hm^2）或过低（150kg/hm^2）施用氮肥均不利于淀粉及其组分含量的提高。只有保持适宜的花后土壤含水量和施适宜的氮肥才有利于支/直比的提高。适量增施氮肥或花后土壤含水量适宜可提高小麦的加工品质。这说明在小麦生产中可以通过施用氮肥和控制花后土壤水分含量技术,调控小麦品质和产量的形成,从而实现优质高产。

抗氧化剂和吲哚生物碱在粉红色和白色长春花植株不同部位中的分布(英文)

目的研究抗氧化剂和吲哚生物碱在2种长春花(粉红色和白色)植株不同部位的分布。方法通过检测无酶活性的抗氧化分子含量和抗氧化酶活性测定抗氧化能力。无酶活性的抗氧化分子包括抗坏血酸、α-生育酚和还原型谷胱甘肽。抗氧化酶包括超氧化物歧化酶、抗坏血酸过氧化物酶、过氧化氢酶、过氧化物酶和多酚氧化酶。所用样品为从田间收集到的植株的根、茎、叶、花和豆荚。结果与其他部位比较,根和茎中抗氧化剂的含量较高,花和豆荚中含量最低。粉红色长春花中抗氧化剂和生物碱含量较高。叶中抗氧化酶的活性较高,但吲哚生物碱的含量在粉红色长春花的根中较高。结论对于抗氧化剂和生物碱含量而言,粉红色长春花更适合培养。

Changes in growth and photosynthetic characteristics of Ocimum sanctum under growth regulator treatments

A field experiment was conducted to investigate the effect of growth regulators on growth characteristics such as root length,shoot length,total leaf area,number of inflorescence per plant,number of flower per inflorescence,whole plant fresh weight and whole plant dry weight.Photosynthetic characteristics were also analyzed based on the same experiment.For this,various photosynthetic pigment contents such as chlorophyll,carotenoid,anthocyanin and xanthophyll content were calculated.The conventional growth regulator abscisic acid(ABA)and non-conventional growth regulator triazole compound paclobutrazol(PBZ)were used.Root length increased due to growth regulator treatment,but shoot length decreased.Leaf area was decreased due to growth regulator treatment.The number of inflorescence increased in ABA treated plants,but it was decreased in PBZ treated plants.In ABA treated plants,the number of flowers per inflorescence was increased.In PBZ treated plants the number of inflorescence was reduced.The whole plant fresh weight(FW)and dry weight(DW)were increased in ABA and PBZ treated plants.There was an increase in chlorophyll content in growth regulator treated plants compared to control,and it was more in PBZ treated plants.The carotenoid content was also increased in ABA and PBZ treated plants.

Marine mycoflora of south India with special emphasis on Lignicolous Marine Fungi

A study dealing with the marine fungi associated with decaying wood samples in the brackish water mangrove ecosystem and shoreline ecosystem was carried out in south India.A total of 19 marine fungi were isolated from the brackish water mangrove ecosystem.They included 13 Ascomycetes,one Basidiomycete and five Mitosporic fungi.In terms of percent frequency of occurrence,the most frequent species obtained from the brackishwater were the Lignincola longirostris(16.60%)and Savoryella lignicola(12.09%).Nine species were found frequently.Five species were occasionally encoun-tered.Aigialus mangrovei,Aniptodera mangrovei and Halosarpheia marina were the rare species recorded.The average number of isolates per wood sample was 1.53.A total of 27 marine fungi including 15 ascomycetes,one basidiomycete and ten mitosporic fungi were recorded from the shoreline ecosystem.In terms of percent frequency of occurrence,the most frequent species obtained from Kanyakumari were the Arenariomyces trifurcates(13.66%),Corollospora maritima(12.44%),and Cirrenalia pygmea(10.98%).Seven species were found frequently.Fourteen species were occasionally encountered.Three species were found to be rare in occurrence.The average number of isolates per wood sample was 1.21.