scholarly journals Syntrichia norvegica shoots exhibit a complex inducible response to desiccation: separating the effects of rate of drying and water content

Botany ◽  
2017 ◽  
Vol 95 (5) ◽  
pp. 481-491 ◽  
Author(s):  
Lloyd R. Stark ◽  
Joshua L. Greenwood ◽  
Mandy L. Slate ◽  
John C. Brinda
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Content ◽  
Desiccation Tolerance ◽  
Severe Damage ◽  
Regeneration Potential ◽  
Significant Damage ◽  
Drying Rates ◽  
Shoot Damage ◽  
Water Contents

Plants in the moss genus Syntrichia are considered to have constitutive desiccation tolerance (DT), as in, able to tolerate a rapid drying event without incurring significant damage upon rehydration. However, few researchers have considered the separate effects of rate of drying and water content, and incorporated fully dehardened (to DT) plants in the experiments. Plants of Syntrichia norvegica F.Weber were cultured under conditions of suprasaturation, and adult shoots were exposed to a range of drying rates and equilibrating relative humidities (RHs), rehydrated, and assessed for chlorophyll fluorescence and regeneration potential. Adult shoots exhibited severe damage across all drying rates when equilibrated at RHs <30%. However, an inducible response to desiccation was present across all water contents as the rate of drying was extended from 0 to 4 d. The least desiccation damage occurred at longer drying times and higher water contents (8 d at 75% RH). A constitutive phenotype for DT was not strictly evident in S. norvegica. Rather, we observed an incomplete pattern of environmentally inducible DT, coupled with heavy shoot damage at lower water contents. Rate of drying and equilibrating RH clearly interact in producing the pattern and strategy of DT for this species.

Effects of differential drying rates on viability retention of recalcitrant seeds of Ekebergia capensis

1998 ◽  
Vol 8 (4) ◽  
pp. 463-471 ◽  
Author(s):  
N. W. Pammenter ◽  
Valerie Greggains ◽  
J. I. Kioko ◽  
J. Wesley-Smith ◽  
Patricia Berjak ◽  
...  
Keyword(s):  
Water Content ◽  
Exponential Function ◽  
Time Course ◽  
Drying Rate ◽  
Recalcitrant Seeds ◽  
Tissue Water ◽  
Initial Water ◽  
Viability Loss ◽  
Drying Rates ◽  
Water Contents

AbstractThe drying rate of whole seeds of Ekebergia capensis (Meliaceae) was shown to influence the response to desiccation, with rapidly dried seeds surviving to lower water contents. Short-term rapid drying (to water contents higher than those leading to viability loss) actually increased the rate of germination. The form of the time course of decline of axis water content varied with drying rate; slow drying could be described by an exponential function, whereas with rapid drying initial water loss was faster than predicted by an exponential function. These observations suggest that slow drying brought about homogeneous dehydration and that the rapid drying was uneven across the tissue. This raised the possibility that the different responses to dehydration were a function of different distributions of water in the axis tissue under the two drying regimes. However, ultrastructural observations indicated that different deleterious processes may be occurring under the different drying treatments. It was tentatively concluded that a major cause of viability loss in slowly dried material was likely to be a consequence of aqueous-based processes leading to considerable membrane degradation. Uneven distribution of tissue water could not be rejected as a contributory cause of the survival of rapidly dried seeds to low bulk water contents. The differential response to dehydration at different drying rates implies that it is not possible to determine a ‘critical water content’ for viability loss by recalcitrant seeds.

scholarly journals Drying and storage of Eugenia involucrata DC. seeds

2003 ◽  
Vol 60 (3) ◽  
pp. 471-475 ◽  
Author(s):  
Angela Maria Maluf ◽  
Denise Augusta Camargo Bilia ◽  
Claudio José Barbedo
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Cold Storage ◽  
Native Species ◽  
Plastic Bags ◽  
Physiological Quality ◽  
Drying Rates ◽  
And Storage ◽  
Water Contents

The physiological quality of seeds of native species is important to produce healthy saplings and therefore guarantee the success of programs to recover disturbed vegetation. This reinforces the necessity for investigating the physiological quality of those seeds. To evaluate the effects of different drying rates on the germination, moisture content and storability of Eugenia involucrata diaspores, mature fruits collected at Mogi Guaçu, SP, Brazil had their epi- and mesocarps removed by washing and were dried at 30, 40 or 50ºC until their water content was reduced from 57% (fresh diaspores) to 13% (final drying), totaling six drying levels. In a second experiment, diaspores had their moisture content reduced from 57% to 49%, at 30ºC, totaling six drying levels (0h, 1h, 2h, 3h, 4h and 5h), and were kept for 180 days in plastic bags under cold storage. The drying rate had no effect on tolerance to desiccation by E. involucrata diaspores; water contents lower than 51% decreased both germinability and storability. Diaspores can be stored for up to 180 days as long as their water content is reduced to 53% and they are kept inside plastic bags under cold storage.

Responses of the moss Tortula ruralis to desiccation treatments. II. Variations in desiccation tolerance

1981 ◽  
Vol 59 (12) ◽  
pp. 2707-2712 ◽  
Author(s):  
Mark W. Schonbeck ◽  
J. Derek Bewley
Keyword(s):  
Water Content ◽  
Desiccation Tolerance ◽  
Dry Weight ◽  
Severe Damage ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Tortula Ruralis

Variations in the apparent desiccation tolerance of the moss Tortula ruralis were traced to several causes. When the moss was kept continuously hydrated for several days, desiccation tolerance tended to decrease ("dehardening"). Conversely, daily episodes of drying and rehydration induced hardening so that the moss could tolerate rapid drying to a tissue water content of 0.008 g∙g dry weight−1.Different clumps of moss showed very different degrees of desiccation tolerance. The least tolerant samples suffered severe damage after rapid drying, whereas the most tolerant suffered little damage, and did not deharden during 3 days continuous hydration.

Some aspects of Sphagnum ecology

1986 ◽  
Vol 64 (2) ◽  
pp. 416-426 ◽  
Author(s):  
Richard E. Andrus
Keyword(s):  
Desiccation Tolerance ◽  
Cation Exchange Capacity ◽  
Environmental Gradients ◽  
Exchange Capacity ◽  
Small Scale ◽  
Desiccation Resistance ◽  
Photosynthetic Response ◽  
Drying Rates ◽  
Water Holding ◽  
Water Contents

Sphagnum species are ecologically prominent wetland plants with xerophytic adaptations and succession-directing acidification capabilities. Species are organized along environmental gradients of pH, cation concentrations, hummock and hollow, wet versus dry, shade versus sun, coastal versus inland, and cold versus warm. The known factors responsible for this organization include cation-exchange capacity, desiccation tolerance, desiccation resistance, water-holding capacity, drying rates, and photosynthetic response at differing water contents. Small-scale distribution of Sphagnum species can be better explained for ombrotrophic sites than for minerotrophic sites.

Winter Survival Evaluation of 172 Groundcovers in Northern Illinois

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 453d-453
Author(s):  
A.M. Shirazi ◽  
E.A. HedBorn ◽  
S.A. Mehaffey ◽  
A.S. Merritt
Keyword(s):  
Cold Resistance ◽  
Winter Hardiness ◽  
Winter Survival ◽  
Severe Damage ◽  
Hedera Helix ◽  
Cold Temperatures ◽  
Ajuga Reptans ◽  
Significant Damage ◽  
Cold Damage ◽  
Euonymus Fortunei

The winter hardiness of many groundcover cultivars in northern Illinois is not well-known. This study was designed to evaluate the survival of 172 plants used in the groundcover path at The Morton Arboretum. Once a month, from Sept.1997 to Jan. 1998, the plants chosen for this study were visually evaluated and their vitality rated on a scale of 1 to 5 (1 = alive, 5 = dead). All nine cultivars of Euonymus fortunei remained virtually unchanged throughout the study period. Among six cultivars of Hedera helix, only `Gold Heart' showed minor damage in November. Nine Heuchera were evaluated and all exhibited excellent resistance to cold temperatures. While all the Pulmonarias studied showed some cold damage by November, `Bielefeld Pink', `Little Blue', `Roy Davidson', Pulmonaria longifolia var. cevennensis, and Pulmonaria officinalis `Sissinghurst White' fared the best for the longest period of time. Five cultivars of Pachysandra terminalis were included in this study. None had significant damage until November, and then only rated a “2.” Of the eight Ajuga evaluated, Ajuga pyramidalis `Metallica Crispa', and Ajuga reptans `Braunherz', `Catlin's Giant', and `Gaiety', exhibited the best cold resistance. Four Polygonums varied widely in their response to cold temperatures, but all showed signs of severe damage in November. Polygonum `Border Jewel' exhibited the best tolerance, rating a “1” in October, but in November it was given a rating of “4.” Their recovery in spring will be compared.

scholarly journals Effects of different drying rates on the physiological quality of Coffea canephora Pierre seeds

2005 ◽  
Vol 17 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Sttela Dellyzete Veiga Franco da Rosa ◽  
Delacyr da Silva Brandão Júnior ◽  
Édila Vilela de Resende Von Pinho ◽  
André Delly Veiga ◽  
Luiz Hildebrando de Castro e Silva
Keyword(s):  
Water Content ◽  
Storage Temperature ◽  
Removal Rate ◽  
Coffea Canephora ◽  
Development Stage ◽  
Seed Vigor ◽  
Drying Rate ◽  
Physiological Quality ◽  
Drying Rates

Desiccation tolerance in seeds depends on the species, development stage and drying conditions, especially the water removal rate. Coffea seeds are considered of intermediate performance, because they tolerate relative dehydration compared to orthodox seeds and are sensitive to low temperatures. The objective of this study was to verify the effect of different drying rates on the viability and storability of Coffea canephora seeds. A complete randomized experimental design was used, in a factorial 3 x 5 x 2 design, with three drying rates (fast, intermediate and slow), five final mean water contents after drying (51, 42, 33, 22 and 15 %) and two storage temperatures (10 and 20°C). The germination and seed vigor assessments, using radicle protrusion, cotyledon leaf opening, seedling emergence and emergence speed index, were performed shortly after drying and after two and four months storage. It was observed that with reduction in the water content there was reduction in the germination values and seed vigor, for all the drying rates. The greatest reductions in physiological quality occurred when the seeds were dried quickly and the best results were obtained at the intermediate drying rate. There was an effect of drying rate and storage temperature on the physiological quality of the seeds, and lower germination and vigor values were observed in seeds with lower water content stored at 20°C. C. canephora seeds were tolerant to desiccation down to 15 % water content and can be stored for four months at 10°C. A temperature of 20ºC can be used to store C. canephora seeds, as long as the water content is not reduced to values below 22 % water content.

MITIGATION YIELD SCALED METHANE EMISSION FROM RICE GROWN IN WATER STRESS CONDITIONS WITH BIOCHAR AND SILICATE AMENDMENTS

2021 ◽  
Author(s):  
MUHAMMAD ASLAM ALI ◽  
SANJIT CHANDRA BARMAN ◽  
MD. ASHRAFUL ISLAM KHAN ◽  
MD. BADIUZZAMAN KHAN ◽  
HAFSA JAHAN HIYA
Keyword(s):  
Water Stress ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Field Capacity ◽  
Saturated Soil ◽  
Rice Grain ◽  
Standing Water ◽  
Water Contents ◽  
Soil Water Contents

Climate change and water scarcity may badly affect existing rice production system in Bangladesh. With a view to sustain rice productivity and mitigate yield scaled CH4 emission in the changing climatic conditions, a pot experiment was conducted under different soil water contents, biochar and silicate amendments with inorganic fertilization (NPKS). In this regard, 12 treatments combinations of biochar, silicate and NPKS fertilizer along with continuous standing water (CSW), soil saturation water content and field capacity (100% and 50%) moisture levels were arranged into rice planted potted soils. Gas samples were collected from rice planted pots through Closed Chamber technique and analyzed by Gas Chromatograph. This study revealed that seasonal CH4 emissions were suppressed through integrated biochar and silicate amendments with NPKS fertilizer (50–75% of the recommended doze), while increased rice yield significantly at different soil water contents. Biochar and silicate amendments with NPKS fertilizer (50% of the recommended doze) increased rice grain yield by 10.9%, 18.1%, 13.0% and 14.2%, while decreased seasonal CH4 emissions by 22.8%, 20.9%, 23.3% and 24.3% at continuous standing water level (CSW) (T9), at saturated soil water content (T10), at 100% field capacity soil water content (T11) and at 50% field capacity soil water content (T12), respectively. Soil porosity, soil redox status, SOC and free iron oxide contents were improved with biochar and silicate amendments. Furthermore, rice root oxidation activity (ROA) was found more dominant in water stress condition compared to flooded and saturated soil water contents, which ultimately reduced seasonal CH4 emissions as well as yield scaled CH4 emission. Conclusively, soil amendments with biochar and silicate fertilizer may be a rational practice to reduce the demand for inorganic fertilization and mitigate CH4 emissions during rice cultivation under water stress drought conditions.

The effect of water deficit on some physiological indices of Indian lettuce (Lactuca indica L.)

2021 ◽  
Vol 66 (1) ◽  
pp. 80-86
Author(s):  
Thin Pham Thi Thanh ◽  
Bang Cao Phi ◽  
Hai Nguyen Thi Thanh ◽  
Khuynh Bui The ◽  
Mai Nguyen Phuong ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Stress ◽  
Water Content ◽  
Flowering Time ◽  
Water Deficit ◽  
Physiological Responses ◽  
Water Deficit Stress ◽  
Flower Formation ◽  
Lactuca Indica ◽  
Wilting Rate

Indian Lettuce (Lactuca indica L.) is a valuable medicinal herb but there are still no many researches about this plant. In this work, the physiological responses of Indian lettuce plants under water deficit conditions (5, 8, and 11 days of water stress) were investigated. The Indian lettuce wilted after 5 days of water stress (66.66%), the wilting rate increased after 8 (93.33%) and 11 days (100%) of water stress. The longer duration of water deficit stress caused the slower recovery of plants after rewatering. The water deficit stress caused a decrease in chlorophyll fluorescence, non-associated water content as well as flower formation of Indian lettuce. But the water deficit stress increases the associated water content and the flowering time of this plant.

scholarly journals Effect of Nano-Carbon on Water Holding Capacity in a Sandy Soil of the Loess Plateau

2017 ◽  
Vol 21 (4) ◽  
pp. 189-195 ◽  
Author(s):  
Beibei Zhou ◽  
Xiaopeng Chen
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Loess Plateau ◽  
Sandy Soil ◽  
Water Retention ◽  
Soil Mixture ◽  
Cumulative Infiltration ◽  
Nano Carbon ◽  
Water Contents ◽  
Soil Water Contents

The poor water retention capacity of sandy soils commonly aggregate soil erosion and ecological environment on the Chinese Loess Plateau. Due to its strong capacity for absorption and large specific surface area, the use of nanocarbon made of coconut shell as a soil amendment that could improve water retention was investigated. Soil column experiments were conducted in which a layer of nanocarbon mixed well with the soil was formed at a depth of 20 cm below the soil surface. Four different nanocarbon contents by weight (0%, 0.1%, 0.5%, and 1%) and five thicknesses of the nanocarbon- soil mixture layer ranging from 1 to 5 cm were considered. Cumulative infiltration and soil water content distributions were determined when water was added to soil columns. Soil Water Characteristic Curves (SWCC) were obtained using the centrifuge method. The principal results showed that the infiltration rate and cumulative infiltration increased with the increases of nanocarbon contents, to the thicknesses of the nano carbon-soil mixture layer. Soil water contents that below the soil-nano carbon layer decreased sharply. Both the Brooks-Corey and van Genuchten models could describe well the SWCC of the disturbed sandy soil with various nano carbon contents. Both the saturated water content (θs), residual water content (θr) and empirical parameter (α) increased with increasing nano carbon content, while the pore-size distribution parameter (n) decreased. The available soil water contents were efficiently increased with the increase in nanocarbon contents.

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