Physiological mechanisms of tolerance to high boron concentration in Brassica rapa

2006 ◽  
Vol 33 (10) ◽  
pp. 973 ◽  
Author(s):  
Sukhjiwan Kaur ◽  
Marc E. Nicolas ◽  
Rebecca Ford ◽  
Robert M. Norton ◽  
Paul W. J. Taylor
Keyword(s):  
Brassica Rapa ◽  
Cell Walls ◽  
Boron Concentration ◽  
Leaf Tissue ◽  
Boron Uptake ◽  
Tolerance Mechanism ◽  
Physiological Mechanisms ◽  
Boron Tolerance ◽  
High Boron ◽  
Sensitive Genotype

Tolerance to high boron concentration in Brassica rapa was primarily due to low net boron uptake by the roots. However, in the two tolerant genotypes, 39–43% of boron uptake was retained in the tap roots, which limited boron accumulation in the leaves, and also contributed to boron tolerance. In the sensitive genotype, 99% of the increase in boron uptake caused by high soil boron accumulated in the leaves, particularly in the leaf margins. Despite higher transpiration rates, lower net boron uptake occurred in the tolerant genotypes. This result cannot be explained by passive boron uptake alone. Active boron efflux was probably responsible for differences in net boron uptake among tolerant and sensitive genotypes. Boron concentration was much lower in the cell walls than in the cell sap of leaves, indicating that storage of boron in the cell walls was not a tolerance mechanism. Despite high boron concentrations in the leaf symplasm, rates of photosynthesis, transpiration and growth were almost unaffected in the tolerant genotypes. The results demonstrate that boron tolerance in Brassica rapa involves boron exclusion at the root level, boron partitioning away from leaves and, as boron accumulates in leaves despite the first two mechanisms, boron tolerance of the leaf tissue itself.

scholarly journals Response of Grafted and Non-grafted Melon Plants to High Boron and Salinity Levels

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 873E-873
Author(s):  
Menahem Edelstein* ◽  
Meni Ben-Hur ◽  
Ron Cohen ◽  
Yosef Burger ◽  
Israela Ravina
Keyword(s):  
Negative Correlation ◽  
Irrigation Water ◽  
Boron Concentration ◽  
High Salinity ◽  
Leaf Tissue ◽  
Fruit Yield ◽  
Foliar Injury ◽  
Greenhouse Study ◽  
Salinity Levels ◽  
High Boron

Excess of boron and salinity in soil and irrigation water can limit the production of melons (Cucumis melo). A greenhouse study was conducted in order to compare the responses of grafted and non-grafted melon plants to combinations of high levels of boron and salinity. Boron levels were 0.25, 0.8, 2.5, 5.0, 10.0 mg·L-1 and salinity levels were 1.8 and 4.6 dS·m-1. Foliar injury caused by boron was more severe in the non-grafted than in the grafted plants. Likewise, boron accumulation in leaf tissue from non-grafted plants was higher than in grafted plants. High salinity led to decreased boron accumulation in the leaves. Fruit yield was decreased only at a boron concentration of 10 mg·L-1, and the decrease in grafted plants was smaller than that in non-grafted plants. A negative correlation was found between boron accumulation in leaves and fruit yield. The results showed that melon plants grafted on Cucurbita rootstock are more tolerant than non-grafted ones to high boron concentrations, and this can probably be explained by the decrease in boron accumulation caused by the rootstock.

scholarly journals Metal–organic frameworks (MOFs) as highly efficient agents for boron removal and boron isotope separation

RSC Advances ◽  
2017 ◽  
Vol 7 (26) ◽  
pp. 16022-16026 ◽  
Author(s):  
Jiafei Lyu ◽  
Hongxu Liu ◽  
Jingshuang Zhang ◽  
Zhouliangzi Zeng ◽  
Peng Bai ◽  
...  
Keyword(s):  
Separation Factor ◽  
Isotope Separation ◽  
Metal Organic Frameworks ◽  
Boron Isotope ◽  
Boron Removal ◽  
Boron Uptake ◽  
Highly Efficient ◽  
Metal Organic ◽  
High Boron

A variety of MOFs were observed with ZIF-8, to our knowledge, showing the highest boron uptake and MIL-101(Cr) with an unprecedentedly high boron isotope separation factor.

A freeze-etch study of plant cell walls for ectodesmata

1974 ◽  
Vol 52 (9) ◽  
pp. 2033-2036 ◽  
Author(s):  
N. C. Lyon ◽  
W. C. Mueller
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Leaf Tissue ◽  
Physicochemical Characteristics ◽  
Outer Cell ◽  
Plantago Major ◽  
Plant Cell Walls ◽  
Phaseolus Vulgaris L ◽  
Epidermal Cell Wall ◽  
Outer Cell Wall

Leaf tissue of Phaseolus vulgaris L. and Plantago major L. was prepared by the freeze-etch technique and examined in the electron microscope for the presence of ectodesmata. No structures analagous to ectodesmata observed with light microscopy could be found in freeze-etched preparations of chemically unfixed material or in material fixed only in glutaraldehyde. Objects appearing as broad, shallow, granular areas in the epidermal cell wall beneath the cuticle were observed in leaf replicas after fixation in complete sublimate fixative, the acid components of the sublimate fixative, or mercuric chloride alone. Because of their distribution and location, these objects can be considered analagous to ectodesmata observed by light microscopists. Because these areas occur only in chemically fixed walls and are localized within the walls in discrete areas, their presence supports the contention that ectodesmata are sites in the outer cell wall with defined physicochemical characteristics.

Effects of Soil-Applied Materials on the Dry Weight and Boron Uptake of Maize Shoots (Zea Mays L.) Under High Boron Conditions

2019 ◽  
Vol 50 (7) ◽  
pp. 811-826 ◽  
Author(s):  
Hakan Çelik ◽  
Murat Ali Turan ◽  
Barış Bülent Aşık ◽  
Sencer Öztüfekçi ◽  
Ali Vahap Katkat
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Dry Weight ◽  
Boron Uptake ◽  
High Boron

Photosynthetic Acclimation of Alocasia macrorrhiza (L.) G. Don

1988 ◽  
Vol 15 (2) ◽  
pp. 107 ◽  
Author(s):  
WS Chow ◽  
L Qian ◽  
DJ Goodchild ◽  
JM Anderson
Keyword(s):  
Charge Density ◽  
Leaf Area ◽  
Cell Walls ◽  
Surface Charge Density ◽  
Leaf Tissue ◽  
O2 Evolution ◽  
Palisade Cell ◽  
Unit Leaf Area ◽  
Unit Leaf ◽  
Growth Irradiance

The photosynthetic acclimation of Alocasia macrorrhiza (L.) G. Don, a species naturally occurring in deep shade in rainforests, has been studied in relation to a wide range of controlled irradiances during growth (~3-780 �mol photons m-2 s-1 of fluorescent or incandescent light, 10 h light/ 14 h dark). At the maximum growth irradiances, the light- and CO2-saturated rates of O2 evolution per unit leaf area were ~4 times as high as at low irradiance, and approached those of glasshouse-grown spinach. Growth at maximum irradiances reduced the quantum yield of O2 evolution only slightly. Changes in the anatomy of leaf tissue, the ultrastructure of chloroplasts and the composition of chloroplast components accompanied the changes in photosynthetic functional characteristics. At low growth irradiance, palisade cell chloroplasts were preferentially located adjacent to the distal periclinal cell walls and had large granal stacks, and the destacked thylakoids had a very low surface charge density. In contrast, at higher growth irradiance, palisade cell chloroplasts were preferentially located adjacent to the anticlinal cell walls; they had small granal stacks, large stromal space, and a high surface charge density on the destacked thylakoids. The number of chloroplasts per unit section length increased with growth irradiance. Ribulosebisphosphate carboxylase activity per unit leaf area increased markedly with irradiance. Photosystem II, cytochrome f and latent ATPase activity per unit chlorophyll increased to a lesser extent. While the chlorophyll a/chlorophyll b ratio increased substantially with growth irradiance, the chlorophyll content per unit leaf area declined slightly. Our results show that coordinated changes in the structure of leaf tissue, and the organisation and composition of chloroplast components are responsible for Alocasia being capable of acclimation to high as well as low irradiance.

scholarly journals Ni–B and Co–B Amorphous Alloys with High Boron Concentration

1979 ◽  
Vol 20 (7) ◽  
pp. 404-406 ◽  
Author(s):  
Akihisa Inoue ◽  
Akihiro Kitamura ◽  
Tsuyoshi Masumoto
Keyword(s):  
Amorphous Alloys ◽  
Boron Concentration ◽  
High Boron

A greater relative growth rate of Brassica rapa L. at low temperatures increases biomass at anthesis

2001 ◽  
Vol 52 (6) ◽  
pp. 645 ◽  
Author(s):  
P. Si ◽  
N. Thurling
Keyword(s):  
Growth Rate ◽  
Brassica Rapa ◽  
Seed Yield ◽  
Negative Correlation ◽  
Low Temperatures ◽  
Leaf Tissue ◽  
Dry Weight ◽  
Controlled Environment ◽  
Relative Growth ◽  
Potassium Leakage

0t, n.s.). These relationships suggested that it might be possible to develop early flowering cultivars with increased seed yield by selecting for higher RGR before anthesis. RGR of BC 2 F 3:4 lines in the field during winter was correlated with RGR at low temperatures (13/4°C) in a controlled environment, suggesting that genotypes producing more dry weight at anthesis grew more at the low temperatures normally experienced in the field. This was supported by a significant (P < 0.05 0.05) negative correlation (r = –0.69**) between growth in the field and potassium leakage from leaf tissue at 4

scholarly journals Microscopic Aspects of Silicon-Mediated Rice Resistance to Leaf Scald

2016 ◽  
Vol 106 (2) ◽  
pp. 132-141 ◽  
Author(s):  
Leonardo Araujo ◽  
Rayane Silva Paschoalino ◽  
Fabrício Ávila Rodrigues
Keyword(s):  
Cell Walls ◽  
Leaf Surface ◽  
Leaf Tissue ◽  
Phenylpropanoid Pathway ◽  
Microscopic Level ◽  
High Concentration ◽  
Great Abundance ◽  
Leaf Scald ◽  
X Ray ◽  
Fungal Hyphae

This study investigated the effect of silicon (Si) on the potentiation of rice resistance against leaf scald at the microscopic level. Rice plants (‘Primavera’) were grown in a nutrient solution containing 0 (−Si) or 2 mM (+Si) Si. The foliar Si concentration of the +Si plants (3.6 dag/kg) increased in comparison with the −Si plants (0.3 dag/kg). An X-ray microanalysis revealed that the leaf tissue of +Si plants infected with Microdochium oryzae had higher peaks and deposition of insoluble Si than that of −Si plants. The high foliar Si concentration for the +Si plants reduced the expansion of leaf scald lesions. Scanning electron microscopy revealed that fungal hyphae and appressorium-like structures of M. oryzae were more abundant in the leaf surface of −Si plants relative to +Si plants. At both histopathological and ultrastructural levels, fungal hyphae grew abundantly into the leaf tissue of −Si plants. By contrast, rice cell walls were rarely degraded and fungal hyphae were often surrounded by amorphous granular material in the leaf tissue of +Si plants. Conidiophores emerged from stomata 36 h after fungal penetration, and conidia were noticed inside the leaf tissue of the −Si plants in great abundance. The collective results of the present study showed a high concentration and deposition of Si and a considerable deposition of phenolic-like compounds in the leaf tissue of +Si plants. These results indicate that the potentiation of the phenylpropanoid pathway in these plants supplied with Si was favorable for the increase in rice resistance to leaf scald.

Composition and susceptibility to rumen microbial degradation of nonmesophyll cell walls isolated from Caucasian bluestem [Bothriochloa caucasica (Trin)] leaf tissue

1991 ◽  
Vol 39 (3) ◽  
pp. 473-477 ◽  
Author(s):  
Edward J. Piwonka ◽  
Jennifer W. MacAdam ◽  
Monty S. Kerley ◽  
John A. Paterson
Keyword(s):  
Microbial Degradation ◽  
Cell Walls ◽  
Leaf Tissue
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