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2. Effects of shading and CO2 enrichment on photosynthesis and yield of winter grown tomatoes in subtropical regions

Creator:
Carmi, A.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
The effects of exposing winter-grown tomato {Lycopersicon esculentum L.) to various sunlight irradiances and CO2 concentrations, on dark respiration (Ro), night respiration (/?},}), net photosynthetic' rate (P^), dry matter production (DMP), yield earliness and yield amount were studied. Plants were grown in greenhouses under controlled temperatures and exposed to: fiill (FS) oř half (HS) sunlight irradiance in combination with atmospheric (A) oř enriched (E) concentrations of 300-330 or 1400-1500 g(C02) m'^, respectively. The of intact leaves at noontime reached 10.7, 15.2, 5.9 and 9.6 pmol(C02) m-2 s-i in treatments of FSA, FSE, HSA and HSE, respectively. The irradiances on the upper leaf surface during the measurements ranged between 160-190 and 450-550 pmol s'^ in the HS and FS treatments, respectively. of leaves which were kept in darkness following the measurement amved at efflux of 2.6, 2.5, 1.4 and 1.4 pmol(C02) m‘2 s'* while their Pn G^etween 20:00 and 24:00) reached values of 0.9, 1.3, 0.8 and 0.8 pmol(C02) treatments of FSA, FSE, HSA and HSE, respectively. Elevating the CO2 concentration from 300 to 1500 g m'^ increased P^ by 16, 28, 30 and 46 % under an irradiance of 160 pmol m‘2 s'*, and 19, 34, 59 and 44 % under irradiance of 320 pmol m-2 s'* in the FSA, FSE, HSA and HSE treatments, respectively. Increasing the measurement irradiance from 160 to 320 pmol m'2 s'* enhanced P^ by 69, 78, 23 and 49 % in an atmosphere of 300 g m-^ CO2, and by 73, 84, 49 and 47 % in an atmosphere of 1500 g m-^ CO2, in the FSA, FSE, HSA and HSE treatments, respectively. DMP was strongly influenced by the different environmental conditions and the total dry matter accumulation in the shoot per plant during 145 d reached 580, 347, 398 and 235 g in the FSA, FSE, HSA and HSE treatments, respectively. CO2 emichment promoted early yield under both full and partial sunlight irradiance. The HSE treatment led to earlier yield harvesting than the FSA and HSA treatments. The yield of the seven first trusses reached 6.8, 4.6, 5.7 and 3.2 kg per plant in the FSA, FSE, HSA and HSE treatments, respectively. Some increase in fruit fresh matter and diameter of fruits was detected in the C02-enrichéd treatments as compared to the non-enriched ones. Thus the combination of moderate shading and CO2 enrichment might provide a more productive option for winter- grown tomatoes in regions of subtropical climate, even in the winter, than the conventional management of aerated greenhouses without CO2 enrichment which are exposed to fiill sunlight.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Formation of photorespiratory glycollate and glyoxylate ín leaf discs of C3-C4 intermediates: reduced sensitivity to external bicarbonate

Creator:
Tirumala Devi, M. and Raghavendra, A.S.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
Accumulation of glycollate or glyoxylate on irradiation of leaf discs in the presence of a-hydroxypyridinemethane sulfonate (a-HPMS) oř glycidate, respectively, was studied in C3-C4 intermediates of Altemanthera species (A. ficoides, A. tenellá) and Paríhenium hysíerophorus in comparison with the partem in C3 or C4 species. The levels of these two photorespiratory metabolites were reduced in the intermediates (< 75 % of that in C3) while being very low in the C4 species (about 10 % of that in C3). The inhibitory effect of bicarbonate on the glycollate or glyoxylate accumulation was pronounced in the C3 species (60 % inhibition), moderate in the intermediates (about 45 %), and very low (< 2 %) in the C4 plants. The negligible effect of bicarbonate on these photorespiratory metabolites in the C4 species is expected to be due to their C4 acid-based C02-concentrating mechanism. In the presence of 5 mM bicarbonate, the levels of glycollate and glyoxylate in the C3 species were similar to those in the C3-C4 intermediates. We speculate that a high intemal CO2 pool, possibly due to an efficient CO2 recycling/refixation mechanism, may be an additional reason besides the partial reduction in photorespiratory enžymic capacity for reduced levels of photorespiratory glycollate/glyoxylate in C3-C4 intermediates.Accumulation of glycollate or glyoxylate on irradiation of leaf discs in the presence of a-hydroxypyridinemethane sulfonate (a-HPMS) oř glycidate, respectively, was studied in C3-C4 intermediates of Altemanthera species (A. ficoides, A. tenellá) and Paríhenium hysíerophorus in comparison with the partem in C3 or C4 species. The levels of these two photorespiratory metabolites were reduced in the intermediates (< 75 % of that in C3) while being very low in the C4 species (about 10 % of that in C3). The inhibitory effect of bicarbonate on the glycollate or glyoxylate accumulation was pronounced in the C3 species (60 % inhibition), moderate in the intermediates (about 45 %), and very low (< 2 %) in the C4 plants. The negligible effect of bicarbonate on these photorespiratory metabolites in the C4 species is expected to be due to their C4 acid-based C02-concentrating mechanism. In the presence of 5 mM bicarbonate, the levels of glycollate and glyoxylate in the C3 species were similar to those in the C3-C4 intermediates. We speculate that a high intemal CO2 pool, possibly due to an efficient CO2 recycling/refixation mechanism, may be an additional reason besides the partial reduction in photorespiratory enžymic capacity for reduced levels of photorespiratory glycollate/glyoxylate in C3-C4 intermediates.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. On finiteness conditions for Rees matrix semigroups

Creator:
Ayik, Hayrullah
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Rees matrix semigroup, periodicity, local finiteness, residual finiteness, and word problem
Language:
English
Description:
Let $T=\mathcal {M}[S;I,J;P]$ be a Rees matrix semigroup where $S$ is a semigroup, $I$ and $J$ are index sets, and $P$ is a $J\times I$ matrix with entries from $S$, and let $U$ be the ideal generated by all the entries of $P$. If $U$ has finite index in $S$, then we prove that $T$ is periodic (locally finite) if and only if $S$ is periodic (locally finite). Moreover, residual finiteness and having solvable word problem are investigated.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

5. Organisation of photosynthetic apparatus of Triticale in relation to productivity

Creator:
Kabanova, S. N., Kabashnikova, L. F., Serduchenko, E. V., Kalituho, L. N., and Chaïka, M. T.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll, genotypes, grain yield, heterosis, hybrids, leaf area, photochemical activity of chloroplasts, plant height, productivity, and seedling length
Language:
Multiple languages
Description:
Chlorophyll (Chl) content, photochemical activity of chloroplasts as well as photosynthetic and crop productivity were studied in different winter hexaploid Triticale (xTriticosecale Witt.) lines and their F1 hybrids. Heterosis enhanced Chl content, photosynthetic potential, photosynthetic productivity, and grain yield only in several F1 hybrids of Triticale. Indication in some genotypes of close correlations among morphological structure, Chl content, photochemical activity of chloroplasts, photosynthetic potential, and plant productivity may be used in breeding practice of Triticale. and S. N. Kabanova ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Responses of gas exchange, chlorophyll synthesis and ROS-scavenging systems to salinity stress in two ramie (Boehmeria nivea L.) cultivars

Creator:
Huang, C.-J., Wei, G., Jie, Y.-C., Xu, J.-J., Zhao, S.-Y., Wang, L.-C., and Anjum, S. A.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, abiotic stress, pigments, lipid peroxidation, antioxidant enzymes, 2, and 581
Language:
Multiple languages
Description:
Ramie (Boehmeria nivea L.) is an important crop that serves as fine fiber material, high protein feedstuff, and valuable herbal medicine in China. However, increasing salinity in soil limits the productivity. We investigated in a greenhouse experiment responses to salinity in two ramie cultivars, Chuanzhu-12 (salt-tolerant cultivar, ST) and Xiangzhu-2 (salt-sensitive cultivar, SS), to elucidate the salt tolerance mechanism of this species. Salinity stress substantially reduced both chlorophyll and carotenoid contents. In addition, net photosynthesis, transpiration rate, stomatal conductance, intercellular CO2 concentration, and the ratio of intercellular CO2 to ambient CO2 were affected, less in ST. Nevertheless, salinity stress markedly improved water use efficiency and intrinsic water use efficiency in both species. Moreover, relative water contents, soluble proteins, and catalase activity were substantially impaired, while proline accumulation and superoxide dismutase activity were enhanced substantially, more in ST. Furthermore, noteworthy increase in peroxidase activity and decrease in malondialdehyde content was recorded in ST, whereas, in SS, these attributes changed conversely. Overall, the cultivar ST exhibited salt tolerance due to its higher photosynthetic capacity, chlorophyll content, antioxidative enzyme activity, and nonenzymatic antioxidants, as well as reduced lipid peroxidation and maintenance of the tissue water content. This revealed the salt tolerance mechanism of ramie plants for adaptation to salt affected soil., C.-J. Huang, G. Wei, Y.-C. Jie , J.-J. Xu, S.-Y. Zhao, L.-C. Wang, S. A. Anjum., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public