水分胁迫对植物线粒体结构和脯氨酸氧化酶活性的影响

水分胁迫期间,小麦幼苗芽鞘和棉花幼苗胚轴细胞内游离脯氨酸浓度增加;但复水后又恢复正常。电镜观察发现线粒体肿大,嵴消失。胞质中出现脂肪滴。气相层析技术分析,发现水分胁迫使线粒体脂肪酸组成及含量有明显变化;不饱和脂肪酸含量增加。随着水分胁迫时间的延长,脯氨酸氧化酶活性也明显下降。设想水分胁迫使线粒体结构和组分发生了不利于脯氨酸氧化酶活性表达的变化,因而抑制了酶活性。     

INFLUENCE OF UPWARD WATER TRANSLOCATION ON UPTAKE OF IONS IN CORN PLANTS

Smith , Richard C. (Rutgers U., New Brunswick, N. J.) Influence of upward water trans location on uptake of ions in corn plants. Amer. Jour. Bot. 47 (9): 724–729. Illus. 1960.—Experiments were performed in which segments of corn roots were surrounded by a nutrient solution which contained radioactive phosphorus, while a second nutrient solution containing no phosphorus was caused to flow upward through the xylem. Results indicate that phosphorus moves radially across the root into the xylem in the absence of any radial water movement, but that increased rate of water movement upward through the xylem increases the rate of radial or inward movement of ions. Results of experiments in which root segments were treated with sodium azide suggest that the movement of phosphorus across the root is independent of, and in competition with, the process of phosphorus accumulation by the cells of the cortex.     

THE EFFECT OF GIBBERELLIC ACID ON THE ABSORPTION AND TRANSLOCATION OF PHOSPHORUS-32 BY BEAN PLANTS

Linck , A. J., and Theodore W. Sudia . (U. Minnesota, St. Paul.) The effect of gibberellic acid on the absorption and translocation of phosphorus-32 by bean plants. Amer. Jour. Bot. 47(2) : 101—105. Illus. 1960.–Plants of Phaseolus vulgaris, variety ‘Black Valentine,‘ treated with 1 p.p.m. gibberellic acid supplied to the roots for 4 hr. were compared with nontreated. plants for phosphorus-32 uptake. Plants treated with gibberellic acid where transpiration was either rapid or restricted absorbed more phosphorus-32 than those not treated. More phosphorus-32 was recovered from plants free to transpire than from plants in high humidity. In plants free to transpire, significantly more phosphorus was present in the treated plants after 28 hr. and significantly more phosphorus-32 accumulated in treated plants in those parts actively growing, i.e., stem apex, second internode and first trifoliate leaf, and in the roots. For plants in high humidity atmosphere significantly more phosphorus-32 was absorbed by the treated plants at the end of 4 hr. than in the non-treated plants and this difference was maintained throughout all times of harvest. For plants in high humidity atmosphere, significantly more phosphorus-32 accumulated in the lower portions, i.e., roots, hypocotyl, first internode and primary leaves, of treated plants than of non-treated plants, while the differences for the second internode, the first trifoliate leaf and the stem apex were not significant between treated and non-treated plants.