Controls on CO 2 Exchange in Two Polytrichum Moss Species. 2. The Implications of Belowground Plant Parts on the Whole-Plant Carbon Balance

Oikos ◽  
1981 ◽  
Vol 36 (3) ◽  
pp. 348 ◽  
Author(s):  
Bjartmar Sveinbjörnsson ◽  
Walter C. Oechel ◽  
Bjartmar Sveinbjornsson

2016 ◽  
Vol 17 (2) ◽  
pp. 76-83 ◽  
Author(s):  
C. J. Harbach ◽  
T. W. Allen ◽  
C. R. Bowen ◽  
J. A. Davis ◽  
C. B. Hill ◽  
...  

The terms used to describe symptoms of delayed senescence in soybean often are used inconsistently or interchangeably and do not adequately distinguish the observed symptoms in the field. Various causes have been proposed to explain the development of delayed senescence symptoms. In this article, we review published reports on delayed senescence symptoms in soybean, summarize current research findings, provide examples of terms related to specific symptoms, and present an overview of the results of a multi-state survey directed to soybean growers to understand their concerns about delayed soybean senescence. Some of these terms, such as green bean syndrome and green stem syndrome, describe symptoms induced by biotic factors, while other terms describe symptoms associated with abiotic factors. Some delayed senescence terms involve the whole plant remaining green while other terms include just the stem and other plant parts such as pods. In the grower survey, 77% reported observing soybean plants or plant parts that remained green after most plants in the field were fully mature with ripe seed. Most respondents attributed these symptoms to changes in breeding and choice of cultivars. At the end of this article, we standardized the terms used to describe delayed senescence in soybean. Accepted for publication 23 March 2016. Published 15 April 2016.



Revista CERES ◽  
2012 ◽  
Vol 59 (5) ◽  
pp. 689-694 ◽  
Author(s):  
Thiago de Oliveira Vargas ◽  
Ellen Rúbia Diniz ◽  
Ricardo Henrique Silva Santos ◽  
Alysson Roberto de Almeida ◽  
Segundo Urquiaga ◽  
...  

Roots effect is not generally considered in studies assessing the performance of crops in response to green manuring. However, such effect can contribute to a better understanding of crop rotation. The aim of this study was to assess the effect of root and shoot of two legumes on the production of cabbage. The experiment was conducted in pots of 10 liters containing substrate of 2:1 soil/sand. The experiment was arranged in a factorial scheme (2x3 + 2) in a randomized block design with five replicates using two legume species (Crotalaria juncea L. and Canavalia ensiformis L), three plant parts (root, shoot, or whole plant), and two additional treatments (mineral fertilization with 100% and 50% of the recommended dose of N for growing cabbage). Pots with legume treatments received mineral fertilizer with 50% of the recommended dose of N for growing cabbage. The experimental plot consisted of a pot containing one plant of cabbage. Legumes were grown in pots and harvested at 78 days. The root biomass was determined in extra pots. Production was assessed using head fresh and dry weight. The application of the whole plant of both legume species reduced cabbage production. However, root or shoot of both legume species was equivalent to 50% of mineral N fertilization required for the cultivation of cabbage.



2016 ◽  
Vol 34 (1) ◽  
pp. 11-24 ◽  
Author(s):  
A. KHALIQ ◽  
F ASLAM ◽  
A MATLOOB ◽  
A JAVAID ◽  
A TANVEER ◽  
...  

Phytotoxic effects of invasive weed Parthenium hysterophorus were studied by using whole plant, leaf and root aqueous extracts at 0, 2.5, 5.0, 7.5 and 10% (w/v) concentrations against germination and early seedling growth of wheat and canola. Studies were carried out both in Petri plates with filter paper as substratum placed in controlled conditions and soil-filled plastic pots placed in open environments. Pronounced variation was noted for phytotoxic activity of different plant parts of parthenium, aqueous extract concentrations, test species, and bioassay techniques. Aqueous parthenium extracts either inhibited or delayed the germination and suppressed seedling growth of test species over control. For both test species, all the germination attributes were suppressed to a greater extent in Petri plates than in plastic pots. Leaf extracts were more suppressive to germination of test species than whole plant and root extracts. Increasing extract concentration beyond 2.5% caused significant reduction in seedling dry biomass of both test species. Aqueous parthenium extract diminished chlorophyll contents of wheat and canola by 32-63% and 29 69%, respectively. Nevertheless, an increase of 9-172% and 22-60% in phenolic contents of wheat and canola was recorded. Canola appeared to be more susceptible than wheat at all extract concentrations. Present study concluded that bioassays conducted under controlled condition using filter paper as substratum may be misleading due to over estimation of allelopathic response and variation in potential of receiver and donor species. Furthermore, it implies that threshold concentrations of allelochemicals for test species in Petri plates are rarely reached under field conditions.



1979 ◽  
Vol 57 (19) ◽  
pp. 1994-1998 ◽  
Author(s):  
Peter L. Tobiessen ◽  
Nancy G. Slack ◽  
Keith A. Mott

The response of photosynthesis and respiration to drying was measured in four species of epiphytic mosses, Ulota crispa (Hedw.) Brid., Neckera pennata Hedw., Anomodon rugellii (C. Mull.) Keissl., and Plagiomnium cuspidatum (Hedw.) T. Kop., from habitats along a desiccation gradient. There was little difference among the mosses in these responses. The relationship of water content to water potential did differ among the mosses, with Plagiomnium, the facultative epiphyte, showing a typical response of more mesic species and the other three showing a more xeric response, i.e., water potential does not begin to fall steeply until a lower water content is reached in Ulota, Neckera, and Anomodon. Both photosynthesis and respiration in all four moss species were quite sensitive to moderate water stress.



2018 ◽  
Vol 7 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Mohd Shahijahan Dar ◽  
◽  
GH. Nabi Joo ◽  
Showkat Ahmad Ganaie ◽  
◽  
...  

Man has used plants since time immemorial to alleviate sufferings and ailments. The present study attempts to explore and document the medicinal plants used against several diseases by the tribal and rural community of Sata Pokhran area of district Pulwama. During the survey from March to September 2017, a total of 28 different plant species belonging to equal number of genera and 16 different families were found to be used as effective remedies. The present study revealed that either whole plant or some plant parts are used to cure different diseases. It was also observed that majority of plant species are used to treat more than one disease and likewise more than one plant species is used to treat a particular disease. The scientific, local and family names of these medicinal plants along with their parts used, mode of administration and ethno medicinal uses are presented in this paper



1985 ◽  
Vol 33 (1) ◽  
pp. 56-59
Author(s):  
P.C. Struik

Differences in digestibility of plant parts from 5 forage maize hybrids are described and related to the differences in whole plant digestibility of crops grown under different conditions. Plant parts differed greatly in digestibility, and the proportions of the DM of the total plant were variable due to numerous physical, chemical, biological and genetic factors. Whole-plant digestibility, however, was fairly constant and predictable. (Abstract retrieved from CAB Abstracts by CABI’s permission)



2018 ◽  
Vol 6 ◽  
pp. 1-5
Author(s):  
Binita Shrestha ◽  
Chandra Bahadur Thapa

The invasive species are the major cause of crop loss, across the globe, mainly due to their allelopathic effects on the growth of crop plants. In this study, we explored the allelopathic effects of Parthenium hysterophorus on germination of two major cereal crops of Nepal, Rice (Oryza sativa) and Wheat (Triticum aestivum). The experiment was conducted at laboratory of Department of Botany, Prithivi Narayan Campus, Pokhara, Nepal during 2017. In laboratory, seeds of rice and wheat were treated with aqueous extracts of P. hysterophorus plant parts viz. root, stem, leaf, inflorescence and whole plant with concentration of 5, 10, 15 and 20%. The experiment was laid out in a complete randomized design (CRD) in a factorial arrangement with three replicates of each test. The result suggests that the effect was more on wheat than on rice. The maximum inhibition in seed germination of rice was recorded by the inflorescence extract however, in wheat seed germination was inhibited by leaf extract. In both rice and wheat, roots were highly affected than shoots because root first encounters the toxic allelochemicals and absorbs it. The highest concentration (20%) of leaf, inflorescence and whole plant extract was found to be most pernicious whereas root and stem were recorded to have little effects.



2021 ◽  
Vol 118 (43) ◽  
pp. e2112825118
Author(s):  
Giovanni Bortolami ◽  
Gregory A. Gambetta ◽  
Cédric Cassan ◽  
Silvina Dayer ◽  
Elena Farolfi ◽  
...  

In the context of climate change, plant mortality is increasing worldwide in both natural and agroecosystems. However, our understanding of the underlying causes is limited by the complex interactions between abiotic and biotic factors and the technical challenges that limit investigations of these interactions. Here, we studied the interaction between two main drivers of mortality, drought and vascular disease (esca), in one of the world’s most economically valuable fruit crops, grapevine. We found that drought totally inhibited esca leaf symptom expression. We disentangled the plant physiological response to the two stresses by quantifying whole-plant water relations (i.e., water potential and stomatal conductance) and carbon balance (i.e., CO2 assimilation, chlorophyll, and nonstructural carbohydrates). Our results highlight the distinct physiology behind these two stress responses, indicating that esca (and subsequent stomatal conductance decline) does not result from decreases in water potential and generates different gas exchange and nonstructural carbohydrate seasonal dynamics compared to drought.



Weed Science ◽  
1994 ◽  
Vol 42 (3) ◽  
pp. 333-339 ◽  
Author(s):  
Carlos J. Fernandez ◽  
Kevin J. McInnes ◽  
J. Tom Cothren

Whole plant studies were conducted to examine the effects of glyphosate on components of carbon balance, transpiration, and biomass partitioning of wheat plants grown in Olton sandy clay loam soil and in a well-aerated fritted clay medium under controlled environmental conditions. Well-irrigated plants were transferred from a nursery room into a test chamber about 48 d after planting. Two to five days later, 12 to 42 ml of a glyphosate solution with a concentration of 480 mg ai L–1were sprayed until full coverage of the foliage. Environmental conditions in the chamber were air temperature 25 C, dew point 18 C, windspeed 1.1 m s–1, and PPFD 1500 mmol m–2s–1(at the top of the foliage) for 12 h daily. Glyphosate treatment resulted in destruction of the root system, as determined at the end of the tests, and at the start of tests using companion plants. Plants grown in soil lost 0.53 kg kg–1of the initial root mass, while this loss was 0.38 kg kg–1in plants grown in fritted clay. Glyphosate treatment rapidly inhibited daily rates of gross carbon uptake and transpiration of wheat plants grown in both media. Effects occurred more than twice as rapidly in plants grown in soil as in fritted day. Similarity in the patterns of inhibition of gross carbon uptake and transpiration suggests that glyphosate may also affect leaf stomata. After applying glyphosate, daily rates of carbon loss increased for 3 d in soil-grown plants but remained almost constant for 10 d in plants grown in fritted clay; thereafter, the rates of carbon loss declined. The early increase or the constancy of carbon loss observed after applying glyphosate was related to catabolic processes occurring in roots.



1992 ◽  
Vol 43 (7) ◽  
pp. 1653 ◽  
Author(s):  
DO Huett ◽  
EB Dettmann

The effect of N application level on uptake and partitioning of nutrients by zucchini squash (Cucurbita pepo L.) cv. Blackjack, head lettuce (Lactuca sativa L.) cv. Monte110 and potato (Solanum tuberosum L.) cv. Sebago was investigated in sand culture experiments with a stable nutrient supply. Plants were grown during 14 (zucchini squash), 8 (lettuce) and 12 weeks (potato). Five nitrate N levels ranging from 2-36 mol m-3 for lettuce and 2-43 mol m-3 for zucchini squash and potato were applied in a complete nutrient solution. Gamma x quadratic response surface models fitted actual nutrient uptake data (R2> 0 . 9 5 ) . From these models, predicted nutrient uptake, partitioning of nutrients between plant parts and nutrient uptake rates were derived. Nitrogen had a pronounced effect on nutrient uptake of all species. The maximum predicted whole plant (excluding roots) uptake of N and K (parenthesis) was calculated (mol m-3 N) for zucchini squash (19.3, 17.7), lettuce (16.5, 12.1) and potato (12.7, 11.2) respectively. An N deficiency (2 mol m-3)did not result in remobilization of nutrients from vegetative to reproductive growth for zucchini squash and potato. Remobilization of N and K from outer leaves to head occurred for lettuce over the last week of the growth period at all N levels. An N deficiency increased partitioning of N and K by 36 and 54% respectively to reproductive growth for zucchini squash compared with adequate N for fresh yield (14 mol m-3), whereas an N deficiency had a negligible effect on partitioning to reproductive growth for potato. Partitioning, as measured by the ratio of nutrients in fruit, head or tuber to whole plant increased over the growth period, and at final harvest, partitioning was lowest for Ca (0.22-0.24 zucchini squash, 0.21-0.32 lettuce and 0.03-0.09 potato) and highest for K (0.39-0.60 zucchini squash, 0.59-0.68 lettuce and 0.63-0.86 potato). Potato tubers and lettuce head, in contrast to zucchini squash fruit, were dominant sinks for N, K and P.



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