摘要:

AbstractBoron‐deficient soybean roots have a rosette appearance at the terminals caused by the death of the root primordium and the initiation of new root primordia. The root tips show some darkening, swelling, and then a collapse of the tissue. The petiole s of B‐deficient plants are very brittle.Physiologically, B‐deficiency in HA‐soybeans does not appear to involve an interference in the transport of photosynthate (C14distribution) or precursors required for citrate synthesis in the roots.More Ca 45 was found in the tops of B‐sufficient than B‐deficient plants, but the opposite trend existed in the root sap. Boron deficiency symptoms were accentuated by maintaining a relatively low pH of the prenutrient solution by the addition

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07854.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe photosynthate consumption in apple fruits in relation to the leaf/fruit ratio was studied in sections of branches of the Graasten and Golden Delicious varieties by exposure to14CO2during July and August. A significant, negative correlation was found between the fixation of14C in the fruits in terms of percent of the total amount of14C absorbed and the leaf/fruit ratio of the branch sections. The leaf area required for the saturation of one fruit was found to be ca. 190 and 230 cm2(14 and 17 leaves) in the case of Golden Delicious, and ca. 400 and 670 cm2(25 and 42 leaves) for Graasten in July and August, respectively, calculated under conditions of large leaf areas per fruit. In such cases a fairly good, reverse proportionality exists between the14C fixation in the fruit in terms of percent and the leaf area expressed in multiples of saturation area. At low leaf/fruit ratios, however, the actual saturation area is found to be lower than the theoretically computed one.The translocation of the14C assimilated in the leaves of the extension shoots or of spurs without fruits to fruits on other spurs was on the whole promoted by a decreasing leaf/fruit ratio in the parts in question; similarly the greatest transport took place on the side where the leaf/fruit ratio was lowest. The fixation was often greatest in the fruit closest to the treated leaves, hut in a number of cases the value was higher for the second closest or even further removed fruits. In this connection the importance of the size of the fruit and the vascular connections is discussed.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07855.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractMeasurements were made of phosphorus uptake by intact tomato plants from solutions labelled with32P. The plants were exposed to low water potentials by the addition of mannitol to culture solutions. The amounts of labelled phosphorus in the roots and in the shoots wore determined after a one‐ or two‐hour period. Down to ‐5.4 atmospheres, the amount of labelled phosphorus in the roots remained constant, hut the amount transported to the shoots was reduced. However, potentials of ‐10.4 atm reduced the amount of labelled phosphorus in both the root and the shoot. Similar results were obtained when plants were tested immediately after water stress was imposed and when tested after water potentials had been lowered gradually.Plants were treated for one hour at low water potentials and then returned to control solutions (−0.4 atm). For a considerable time, these plants had a much lower phosphorus uptake than plants which had remained continuously at −0.4 atm. These data support the idea that a disturbance in mineral nutrition is partly responsible for reduced growth in plants which experience a moderate wa

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07856.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractLowering the water potential of culture solutions from −0.4 to −5.4 atm reduced both phosphorus and bromide transport to the shoot, hut the content in the roots was not affected. Reductions in phosphorus transport to the shoot were measured during the first four hours of treatment and were related to concurrent decreases in water flow and not to an impairment of active phosphorus transport. The effect of low water potential on phosphorus transport to shoots was similar at external phosphorus concentrations between 0.6 and 15 mg/l.Phosphorus transport was greater in the dark at −0.4 atm than in the light at −5.4 atm even when these treatments gave the same overall rates of water flow; this is attributed to a different pattern of water flow through the various root zones. The results suggest that the main effect of water flow on anion transport to shoots occurred after the ions had been actively adsorbed by the roots and was not due to mass flow increasing ion delivery to sites of active

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07857.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY