密度对玉米群体冠层内小气候的影响

 系统研究了两个玉米(Zea mays L.)品种不同密度群体冠层内光合有效辐射、CO2浓度、温度、风速、相对湿度等小气候因子垂直分布及其变化。指出,密度能显著影响小气候因子在群体中的分布,并最终反映在群体的有效贮积能量上。通过合理密植能调节群体结构、充分利用小气候资源,获得较高有效贮积能量。     

IN VITRO CULTURE OF EAR SHOOTS OF ZEA MAYS AND THE EFFECT OF KINETIN ON SEX EXPRESSION

Immature ear primordia of maize when cultured on a defined liquid medium grew and differentiated in response to two variables: 1) size of initial explants and 2) concentration of kinetin in the medium. Overall growth of primordia, less than 15 mm at explanting, reached an optimum fresh weight and ear length when kinetin was 10^–6m. Ears less than 10 mm, in the presence of kinetin, produced many male spikelets with well-developed stamens in both upper and lower flowers. Ears greater than 15 mm, at explanting, produced only female flowers regardless of the kinetin concentration. Different proportions of male and female and bisexual flowers were produced depending upon the initial size of inflorescences and the concentration of kinetin.     

螺旋藻在体外对双歧杆菌及乳杆菌增殖的促进作用

通过用改良的ＴＰＹ和ＧＡＭ培养基作为螺旋藻的基质,在试管内证实了螺旋藻对双歧杆菌、乳杆菌生长的促进作用。结果显示,钝顶螺旋藻在实验浓度下,对双歧杆菌和乳杆菌的增殖作用与对照组相比有非常显著的差异,这一结果也说明了钝顶螺旋藻在调整肠道菌群,改善肠道内环境方面的作用。     

城市化对植物生长发育的影响

 本文研究了北京市首钢工业区和樱桃沟游览区生态条件的变化及城市化对植物生长发育的影响。两个功能区的气温、相对湿度、降雨量以及雨水、飘尘、植物中的污染物质含量都有很大差异。工业区大多数植物的开花期、结果期比游览区早,而营养结束期延晚;有些植物甚至不能开花、结果;有些虽能正常开花,但花的数量少,结的果实也小等;游览区九种乔木、灌木的叶面积和四种常绿乔木的枝条年生长量都比工业区大0.5—1倍。     

酸沉降地区大气汞对土壤-植物系统汞累积影响的调查研究

按酸沉降危害程度的差异及不同功能区,进行了大气、植物、土壤汞的同步调查采样分析。结果表明,大气汞对土壤－植物系统汞累积的影响非常明显,土壤、植物含汞量均随大气汞浓度的升高而升高,土壤－植物系统汞累积与大气汞浓度有显著的相关（相关系数分别为ｒ植＝０．８８２＊＊,ｎ＝５３;ｒ土＝０．７４１＊＊,ｎ＝５２）。调查还发现,当大气汞浓度大于３０ｎｇ／ｍ３时,土壤－植物系统汞累积较为明显,因此把３０ｎｇ（Ｈｇ）／ｍ３作为本地区大气汞对土壤－植物系统造成二次污染的临界浓度     

施水量变化对毛乌素沙地优势植物形态与生长的影响

 以毛乌素沙地优势植物沙柳(Salix psammophila)、杨柴(Hedysarum mongolicum)、油蒿(Artemisia ordosica)和柠条(Caragana intermedia)为对象,人工控制4种施水量来研究这4种植物形态和生长对模拟降水量变化的响应。结果表明不同施水量显著影响着沙柳、杨柴、油蒿和柠条的分枝格局、叶片、生物量及其分配,并且这4种植物的以上特征对不同施水量的响应也有明显差异。在157.5 mm和630.0 mm的施水量之间,施水量的增加对沙柳、油蒿和杨柴枝叶形态     

THE EFFECT OF LIGHT INTENSITY AND TEMPERATURE ON PLANT GROWTH AND CHLOROPLAST ULTRASTRUCTURE IN SOYBEAN

Soybean plants grown in controlled environment cabinets under light intensities of 220 w/m² or 90 w/m² (400–700 nm) and day to night temperatures of 27.5–22.5 C or 20.0–12.5 C in all combinations, exhibited differences in growth rate, leaf anatomy, chloroplast ultrastructure, and leaf starch, chlorophyll, and chloroplast lipid contents. Leaves grown under the lower light intensity at both temperatures had palisade mesophyll chloroplasts containing well-formed grana. The corresponding leaves developed under the higher light intensity had very rudimentary grana. Chloroplasts from high temperature and high light had grana consisting of two or three appressed thylakoids, while grana from the low temperature were confined to occasional thylakoid overlap. Spongy mesophyll chloroplasts were less sensitive to growth conditions. Transfer experiments showed that the ultrastructure of chloroplasts from mature leaves could be modified by changing the conditions, though the effect was less marked than when the leaf was growing.     

重金属在食用菌中的富集及对其生长代谢的影响

本文报导食用菌对重金属的吸收积累性能及重金属对食用菌生长代谢的影响。从供试的香菇、凤尾菇、金针菇及木耳等食用菌研究表明:对Hg、Pb、As、Ni、Cd、Cu、Zn等重金属均有不同程度的富集作用,其中对Hg的富集是极显著的,但对Pb则不明显。从福建省食用菌生产点采样测定结果看,子实体中的重金属含量均不超标。上述重金属对食用菌生长均有不同程度的不良影响,尤其以Hg和As为突出。对产量影响的顺序以香菇最大、凤尾菇次之、金针菇较弱。重金属在一定范围内对香菇抗坏血酸氧化酶活性有激活作用,对纤维素酶有抑制作用。     

温度和水分状况对几种不同类型植物叶片水势和延伸生长的影响

在田间条件下研究了温度、相对湿度、土壤水分对玉米、高粱、茄子、豇豆、河北杨和泡桐六种植物LER2)和ψWL3)日变化的影响。结果表明,ψWL日变化呈正弦曲线,即早晨、晚上高,中午低;土壤水分亏缺,中午大气ψWV4)愈低,ψWL降低愈多。在土壤供水良好的条件下,玉米、高粱、河北杨、泡桐叶片生长与温度密切相关,因此白天生长快,晚上生长慢;若中午ψWV太低,生长减慢,使叶片生长呈双峰曲线,即午前及18:00左右生长快。若土壤水分亏缺,白天ψWV太低,白天生长慢,晚上生长快。茄子和豇豆叶片生长对水分亏缺更敏感,晚上生长快,白天生长慢,干旱处理叶片在白天中午有收缩现象。