ISSN:0190-4167    

DOI:10.1080/01904168709363625

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Iron deficiency chlorosis remains an economically important plant nutrition problem after decades of research. However, basic research on Fe nutrition has provided much information important to a general understanding of plant nutrition, including: 1) chemical equilibria in nutrient solutions and xylem and phloem fluids; 2) regulation of the root's Fe uptake potential to meet the availability of Fe to the root; 3) localization of ferric reduction, Fe‐uptake, and proton excretion in young parts of roots (<3cm from tip) of main and lateral roots; 4) excretion of ligands (phytosiderophores) by graminae to facilitate cation diffusion and uptake; 5) excessive phosphate use as pH buffer in nutrient solutions confounds plant research compared to other buffers; and 6) uptake of Fe by plants under sterile conditions shows uptake is a fundamental plant capability; however, plants may also use Fe from some microbial siderophores.

ISSN:0190-4167    

DOI:10.1080/01904168709363626

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The effect of iron deficiency on the amount of photosynthetic pigments per unit leaf area was investigated into two fruit tree species, apricot and pear, grown in the field. Iron deficiency reduced the amount per area of all pigments, but the extent of the reduction depended on the particular pigment affected. The concentration of lutein per unit area was the least affected by iron deficiency. When compared to green leaves, iron deficient leaves which had lost about 85 percent of their chlorophyll a and other pigments, conserved about 30 percent of their lutein Tper area). The relationships between neoxanthin and chlorophylla, and between β‐carotene and chlorophyll a were practically linear. The ratio between chlorophyllaand chlorophyllbincreased only when the chlorophyllacontent fell below 6–8 μg cm‐2, i.e. in fully chlorotic leaves.

ISSN:0190-4167    

DOI:10.1080/01904168709363627

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An HPLC method for MAs (mugineic acid and its analogues) analysis was established. By this method, time course change of MAs secreted from the roots of Fe‐deficient barley were traced. After about one week of ‐Fe treatment, MAs secreted from the roots gradually increased and after 40 days it became plateau. The several MAs were synchronously secreted from the roots throughout a day; their amounts were maximum at noon. The pattern of MAs secretion was different from that of amino acids. MAI was found to be trace in roots, xylem sap and shoots of the control (+Fe) plant. However, MAs concentrations remarkably increased in those tissues when Fe‐deficiency chlorosis progressed due to ‐Fe treatment. From experiments of14CO2‐fixation by photosynthesis,14C‐MA1 secreted from the roots was found to be biosynthesized with a half‐life of 24 h.

ISSN:0190-4167    

DOI:10.1080/01904168709363628

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The changes in the ultrastructure of barley root cells induced by Fe‐deficiency was investigated in relation to secretion of mugineic acid and its analogues (MAS). We found that the particular vesicles were present in barley root cells under both conditions of sufficient and deficient iron. These particular vesicles were increased in number and volume under Fe‐deficient condition. These vesicles contained fibrous materials. Their limiting membrane was thinner than that of Golgi vesicles, and they had ribosomes around their surface. Their structure suggests that they originated from rough endoplasmic reticulum. The vesicle volume was expanded especially before sunrise when MAs were enriched in Fe‐deficient barley roots. In the midday, after secretion of MAs, the volume of the vesicles decreased.

ISSN:0190-4167    

DOI:10.1080/01904168709363629

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Metabolic changes in Fe‐deficient apple seedlings were investigated. Apple seedlings released reducing compounds into the root environment and reduced Fe3+when set into an agar FE‐EDTA plus BPDS (batho‐phenanthroline disulfonate) mixture. Reduction of Fe was clearly visible as a red color around the root‐zone. Leakage from the root was also demonstrated by pH changes and increased electrical conductivity. Iron‐deficient plants had chlorotic leaves, photosynthesis (Pn) was decreased, sugar content was lower but acid content was higher throughout the entire plant. Succinic, malic and citric acids were all increased in the leaves that developed under Fe‐stress conditions, compared to pre‐stressed levels.. The reason for the increase in acid content was not apparent but it helps to explain the leakage of reducing compounds from the roots of Fe‐deficient plants.

ISSN:0190-4167    

DOI:10.1080/01904168709363630

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In calcareous soils, chickpea cultivars frequently exhibit symptoms of lime‐induced chlorosis and reduced yield. This behavior is influenced by genetic and physiological factors. Five chickpea lines (ICCL 81192, ILC 263, ILC 482, ILC 2643 and a local Lebanese cultivar), were grown for 10 weeks in soils of varying CaC03 content with and without added Fe and K. Plants were rated for Fe chlorosis resistance and analyzed for chlorophyll, Ca, Mg, K, P, and active and total Fe. In the 63% CaCO3soil, both ILC 482 and ILC 263 were highly resistant to Fe chlorosis, the Lebanese local cultivar was moderately resistant, whereas ICCL 81192 and ILC 2643 were chlorosis susceptible. However, no line was fully resistant in the soil with 82% CaCO3. Chlorosis was alleviated by Fe‐EDDHA treatment, but K2SO4had only a slight effect in delaying the onset of chlorosis. Visual chlorosis rating was negatively correlated with leaf chlorophyll content and dry weight of aerial plant tissue. In the non‐calcareous soil, susceptible lines had higner concentrations of K+and Fe3+than resistant ones. As chlorosis progressed in susceptible lines grown on calcareous soils, plant Fe2+and Fe3+concentrations decreased, while Ca, K and Mg increased. Genetic studies indicated that a single recessive gene may control susceptibility of lime‐induced chlorosis in chickpea.

ISSN:0190-4167    

DOI:10.1080/01904168709363631

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

We studied the changes with time in the composition of leaves of different age, with particular attention given to the youngest leaves, because relatively little is known of the effect of iron chlorosis on the elemental composition of groundnut leaves (Arachis hypogaeaL.).

ISSN:0190-4167    

DOI:10.1080/01904168709363632

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Several crop cultivars were tested for their Fe‐deficiency stress tolerance and susceptibility, using solution culture with Fe and without Fe. The criteria employed were the onset of and recovery from chlorosis and change in pH. While in sorghum, peanut, cotton, sesame, and chickpea, the recovery was associated with decrease in pH, there was no relationship between these two factors in lentil, in which two cultivars behaved differently. In VI‐1, the pH decreased only to a small extent, but the plants turned green. On the other hand, in S‐34, the pH decreased considerably but no recovery was obtained.

ISSN:0190-4167    

DOI:10.1080/01904168709363633

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The influence of ammonium/nitrate ratio on the chlorophyll content and induction of chlorosis under low‐pressure sodium (LPS)‐lamps was examined in two cultivars ofChrysanthemum morifoliurnRamat. ('Mountain Snow’ and ‘Fiesta') found previously to differ in sensitivity to water stress. Plants were grown in a peat moss‐vermiculite mix under controlled environments for 39 days under LPS lamps at a photosynthetic photon flux of 320 umol s‐1m‐2. Plants were fertilized twice daily with one of three complete nutrient solutions containing nitrogen at a NH4/NO3ratio: of 0/100; 50/50; or 100/0. Significant differences in the severity and rate of development of chlorosis were observed depending upon the genotype and NH4/NO3ratio. Drought‐tolerant ‘Fiesta’ showed little chlorosis after 39 days of treatment while drought‐sensitive ‘Mountain Snow’ exhibited marked bleaching of the leaves as the percentage of NH4in the solution increased. Bleaching appeared first in the youngest leaves on the main shoot and lateral shoots and proceeded basipetally. Increasing the NH4/NO3ratio from 0/100 to 100/0 hastened the onset of chlorosis in the primary and secondary leaves of NH4‐sensitive ‘Mountain Snow’ by 8–9 days. After 39 days, both cultivars displayed chlorosis, even at 100% NO3, indicating that this damage was probably not caused by NH4treatment alone, but was enhanced by high NH4. These findings thus demonstrate an interaction between spectral quality and NH4nutrition in growth chamber‐grown chrysanthemum.

ISSN:0190-4167    

DOI:10.1080/01904168709363634

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor