无机营养对春小麦抗旱适应性的影响

本文研究了无机营养对春小麦一些抗旱适应性的影响,主要包括:渗透调节的大小和变化过程、可溶性糖的积累、脯氨酸的积累、叶片导度的变化、离体叶片的失水速率、叶面积和耗水量的变化、根系生长和根/植冠值,并且分析了各个处理植株的水分利用效率(WUE)和产量的变异。认为,在干旱条件下,无机营养对于春小麦不同器官、不同生理功能,并不都具有一致的作用。有的利于提高植株的抗旱性,有的可以改变一些适应性产生的时间和发展过程,有的则不利于植株的抗旱性。通过综合分析,提出旱地施肥使作物增产的主要原因是,营养元素满足了作物生长所需,促进了根系发育,利于吸收水分、维持水分平衡和正常生理功能,但对作物自身的耐旱性并没有产生显著影响。     

土壤干旱条件下磷素营养对春小麦水分状况和光合作用的影响

研究了土壤干旱条件下磷素营养对春小麦水分状况和光合作用的影响。结果表明：土壤干旱下,磷素营养明显改善了春小麦的水分状况,维持了较高的ψｗ和ＲＷＣ,并因而导致了较高的净光合速率和较大的气孔开度。不同干旱程度下,限制春小麦光合的因子并不相同,轻度干旱下,光合降低主要是气孔的作用,而严重干旱下则主要是非气孔因子的作用。无论何种水分水平下,施磷处理的净光合速率皆高于不施磷处理,与其较大的气孔导度和叶肉光合     

THE ANATOMY OF INTERNAL TIPBURN OF CABBAGE

Leaves of resistant and susceptible breeding lines of two closely related varieties of cabbage, ‘Glory’ and ‘Globe,’ showing internal tipburn were examined anatomically. Since both resistant and susceptible lines developed tipburn, the type of injury rather than the amount was considered. Regardless of the degree of resistance, cellular disorders in the tipburned areas were the same. Early symptoms showed small gray areas at the lobes of the leaves. The outer parenchymatous cells of these areas remained normal. Some of the xylem vessels became occluded with a granular substance; surrounding cells, including the idioblasts, enlarged. The idioblasts, reported to contain the enzyme myrosin, contained a particulate substance. Some idioblasts hypertrophied and also divided resulting in the distribution of the particles to additional cells. The conditions causing tipburn also affected cell walls, causing thickening and the production of pectic warts between cells and on walls facing the intercellular spaces. As more xylem vessels became occluded, and as the number of idioblasts with particles increased, the cells at the periphery of the leaf collapsed.     

THE NUTRITION OF LETTUCE

In 1935, nutritional work on lettuce was started by the author. The investigations were divided into three sections: sand-culture experiments, soil-culture experiments, and field-fertilizer trials. The results of the sand-culture work have been published (Woodman, 1936, 1939 a, b, c, d , 1940 a, b ); the present paper deals with the results obtained so far from soil cultures and field trials.     

酸白菜发酵中乳酸菌群的分析

酸泡菜是世界性大众化蔬菜发酵制品,其主要发酵菌群是乳酸菌。对西式泡菜、朝鲜泡菜、四川泡菜发酵过程中微生物区系已有较多研究,进而探索出接种微生物纯培养物促进蔬菜发酵的新方法,用于工业生产。但对酸白菜这一中国特有发酵制品的微生物学研究及接种后发酵过程中乳酸菌种类的变化,国内尚未见报道。 我们根据接种发酵和自然发酵对比试验结果,分析不同发酵过程中乳酸菌种类及其变化,说明接种乳酸杆菌促进酸白菜发酵的作用机理。 1