Imbibitional Chilling Injury Research Articles

Quantitative proteomics analysis reveals the response mechanism of peanut (Arachis hypogaea L.) to imbibitional chilling stress.

Imbibitional chilling stress inhibits normal seed germination and seedling establishment and leads to large losses in peanut production. This is a major limiting factor when sowing peanut earlier and further north. To reveal the response mechanism of peanut to imbibitional chilling stress, a Tandem Mass Tag (TMT)-based quantitative proteomics analysis was conducted to identify differentially accumulated proteins (DAPs) under imbibitional chilling stress. Hormone profiling and transcriptional analysis were performed to confirm the proteomics data. Further seed priming analysis with exogenous cytokinins was conducted to validate the role of cytokinins in alleviating imbibitional chilling injury. A total of 5029 proteins were identified and quantified in all of the experimental groups. Among these, 104 proteins were DAPs as compared with the control. Enrichment analysis revealed that these DAPs were significant in various molecular functional and biological processes, especially for biosynthesis and metabolism of plant hormones. Hormone profiling and transcription analysis suggested that the reduced abundance of cytokinin oxidase may be caused by down-regulation of gene expression of the corresponding genes and leads to an elevated content of cytokinins under chilling stress. Seed priming analysis suggested that exogenous application of cytokinins may alleviate injury caused by imbibitional chilling. Our study provides a comprehensive proteomics analysis of peanut under imbibitional chilling stress, suggesting the role of plant hormones in the response mechanism. The results provide a better understanding of the imbibitional chilling stress response mechanism in peanut that will aid in peanut production.

Transcriptome Analysis of Chilling-Imbibed Embryo Revealed Membrane Recovery Related Genes in Maize.

The delayed seed germination and poor seedling growth caused by imbibitional chilling injury was common phenomenon in maize seedling establishment. In this study, RNA sequencing technology was used to comprehensively investigate the gene expressions in chilling-imbibed maize embryo and to reveal the underlying mechanism of chilling injury at molecular level. Imbibed seeds for 2 h at 5°C (LT2) were selected and transcriptomic comparative analysis was performed. Among 327 DEGs indentified between dry seed (CK0) and LT2, 15 specific genes with plasma membrane (PM) relevant functions belonging to lipid metabolism, stress, signaling and transport were characterized, and most of them showed down-regulation pattern under chilling stress. When transferred to 25°C for recovery (LT3), remarkable changes occurred in maize embryo. There were 873 DEGs including many PM related genes being identified between LT2 and LT3, some of which showing significant increase after 1 h recovery. Moreover, 15 genes encoding intracellular vesicular trafficking proteins were found to be exclusively differential expressed at recovery stage. It suggested that the intracellular vesicle trafficking might be essential for PM recovery through PM turnover. Furthermore, transcriptome analyses on imbibed embryos under normal condition (25°C) were also made as a contrast. A total of 651 DEGs were identified to mainly involved in protein metabolism, transcriptional regulation, signaling, and energy productions. Overall, the RNA-Seq results provided us a deep knowledge of imbibitional chilling injury on plasma membrane and a new view on PM repaired mechanism during early seed imbibition at transcriptional level. The DEGs identified in this work would be useful references in future seed germination research.

How membranes organize during seed germination: three patterns of dynamic lipid remodelling define chilling resistance and affect plastid biogenesis.

Imbibitional chilling injury during germination causes agricultural losses, but this can be overcome by osmopriming. It remains unknown how membranes reorganize during germination. Herein, we comparatively profiled changes of membrane lipids during imbibition under normal and chilling temperatures in chilling-tolerant and -sensitive soybean seeds. We found three patterns of dynamic lipid remodelling during the three phases of germination. Pattern 1 involved a gradual increase in plastidic lipids during phases I and II, with an abrupt increase during phase III. This abrupt increase was associated with initiation of photosynthesis. Pattern 3 involved phosphatidic acid (PA) first decreasing, then increasing, and finally decreasing to a low level. Patterns 1 and 3 were interrupted in chilling-sensitive seeds under low temperature, which lead a block in plastid biogenesis and accumulation of harmful PA, respectively. However, they were rescued and returned to their status under normal temperature after polyethylene glycol osmopriming. We specifically inhibited phospholipase D (PLD)-mediated PA formation in chilling-sensitive seeds of soybean, cucumber, and pea, and found their germination under low temperature was significantly improved. These results indicate that membranes undergo specific and functional reorganization of lipid composition during germination and demonstrate that PLD-mediated PA causes imibibitional chilling injury.

Priming with moringa leaf extract reduces imbibitional chilling injury in spring maize

This study investigated the potential of moringa leaf extract (MLE) in seed priming for vigour enhancement of spring maize sown at low temperature (12 ± 1°C). The efficacy of MLE priming (3% w/v) was compared with other priming agents: kinetin (0.5% w/v), KCl (2% w/v) and hydropriming, each for 18 hours in hybrid maize cv. Pioneer-6525. Non-primed seeds were used as the control. Priming with MLE was the most effective in improving germination rate and subsequent seedling growth. This increased seedling performance was the result of reduced time to 50% germination (T50) and mean germination time (MGT), and higher final germination percentage (FGP), germination index (GI) and germination energy (GE). Similarly improved seedling growth following seed priming with MLE or kinetin was due to enhanced root and shoot lengths, the ratio of root:shoot length and maximum seedling fresh and dry weights compared with control seeds. Enhanced seedling maize performance by priming with MLE was attributed to improved chlorophyll content, amylase activity and total sugar contents under cool conditions.

Ascorbate–glutathione cycle of mitochondria in osmoprimed soybean cotyledons in response to imbibitional chilling injury

Osmopriming treatment of chilling-sensitive soybean ( Glycine max L. cv. Zhonghuang-22) seeds for 72 h at 25 °C with polyethylene glycol (PEG8000) solution at −1.5 MPa strongly improves chilling resistance. The aim of the present work was to investigate whether the beneficial effect of osmopriming is associated with restoration of the ascorbate–glutathione (ASC–GSH) cycle of mitochondria in soybean seeds. Compared with the control, both H 2O 2 and malondialdehyde (MDA) contents in mitochondria of osmoprimed seeds decreased after chilling treatment, and these changes were associated with increased activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and l-galactono-γ-lactone dehydrogenase (GLDH). However, the activity of dehydroascorbate reductase (DHAR) showed no obvious change during osmopriming treatment. Increased ASC and GSH contents accompanied prolonged osmopriming, and the reduced/oxidized ratios of ASC and GSH increased differently during osmopriming. These results indicate that osmopriming treatment enhances activity of the ASC–GSH cycle of mitochondria, which raises the chilling tolerance in soybean seeds and protects against H 2O 2 that is generated in mitochondria during imbibition at low temperature.

Changes of plasma membrane H+-ATPase activities of Glycine max seeds by PEG treatment

The soybean (Glycine max) Heihe No. 23 is sensitive to imbibitional chilling injury. Polyethylene glycol (PEG) treatment can improve chilling tolerance of soybean seeds to a certain extent. The changes of hydrolytic ATPase in plasma membranes and H+-pumping responses in soybean seeds were investigated during PEG treatments. Effects of exogenous calcium and exogenous ABA on the hydrolytic ATPase were also examined in order to understand the mechanism of chilling resistance. Highly purified plasma membranes were isolated by 6.0% aqueous two-phase partitioning from soybean seeds, as judged by the sensitivity of hydrolytic ATPase to sodium vanadate. PEG treatment resulted in a slight increase of the hydrolytic ATPase activity in 12 h. Then the activity decreased gradually, but still higher than the control. The H+-pumping activity increased steadily during PEG treatment. Exogenous calcium had both activating and inhibiting effects on the hydrolytic ATPase, but the activity was inhibited in soybean seeds treated with exogenous ABA. Results suggested that PEG treatment, not the exogenous calcium and ABA, up-regulated H+-ATPase activities in soybean seeds.

The impact of film coating on initial water uptake and imbibitional chilling injury in high and low vigor sh2 sweet corn seeds

The impact of film coating on initial water uptake and imbibitional chilling injury in high and low vigor sh2 sweet corn seeds

Peroxidative changes associated with chilling injury in soybean seeds during imbibition

Summary The relationship between lipid peroxidation and fatty acid unsaturation was investigated during imbibitional chilling injury in soybean seeds. Transient changes in lipid hydroperoxide levels were observed in both chilled and non-chilled seeds and axes. However in axes the increase in lipid hydroperoxides after 12 hours of imbibition at chilling temperatures was associated with small but non-significant declines in the levels of linoleic acid, and linolenic acids (9 % and 8 % respectively) of the total lipid fraction. Increases in lipid hydroperoxides during the chilling of whole seeds and embryonic axes preceded ion leakage by some 40 hours. In an attempt to separate temperature effects from the imbibition process, seeds and axes were imbibed for 12 hours at 5 °C or 25 °C before transfer to 25 °C or 5 °C, respectively. Seeds showed no significant changes in fatty acid levels, although axes showed marked changes in the levels of linoleic acid. The capacity of soybean seeds to control lipid peroxidation may be an important component in chilling injury and lead to a loss of unsaturated fatty acids.

Chilling injury in germinating seeds: basic mechanisms and agricultural implications

AbstractGerminating seeds of many species, especially those of tropical or subtropical origin, suffer chilling injury when exposed to low but non-freezing temperatures, resulting in poor seedling establishment and reduction in yield. The severity of injury depends upon several factors such as (i) the species or the cultivars involved, (ii) the initial water content of the seed, (iii) the temperature to which seed is exposed, (iv) the duration of chilling exposure and (v) the period during the course of germination when the chilling exposure takes place. The period of imbibition by seeds is the period of sensitivity to the stresses but especially to chilling temperatures. Imbibitional chilling injury is defined as sensitivity to a combination of low seed-water content and imbibition at cold temperature. The mechanism of chilling injury in seeds is different from chilling injury of hydrated tissues and is discussed in relation to the involvement of membranes, respiration, rate of hydration and the concept of discreet moisture levels. Furthermore, the mechanistic and applied aspects of pre-sowing seed treatments for improved germination performance under chilling stress are discussed with an emphasis on hydration-dehydration, osmotic priming and growth regulator treatments.

Influence of Seed Hydration on Seedling Performance

Water is pervasively involved in the life cycle of seeds. Water in the environment, either as a vapor or liquid, directly affects seed moisture status. This article is devoted to the study of seed moisture status in postharvest events. Two topics are discussed: imbibitional chilling injury and upgrading of primed seeds. Imbibitional chilling injury is a physiological disorder that occurs in large-seeded legumes as well as other important agronomic seeds. Imbibitional chilling injury has been shown to reduce the survival rate of seedlings. Surviving seedlings have less emergence force per seedling and require a longer period to generate maximum force. Rapid hydration has been shown to induce injury at a particular seed moisture level. Methods of regulating the hydration rate were explored to alleviate chilling injury in snap beans (Phaseolus vulgaris L.) Plant breeding lines with the semihard seed characteristic delayed the onset of imbibition when the initial moisture level was low (8%). Coating seeds with polymeric films to complement the permeable testa retarded the imbibition rates. Both approaches alleviated chilling injury and improved seedling establishment under stressful conditions. Seed priming is a technique for elevation of seed moisture content before sowing. Primed seeds generally emerge more quickly than nonprimed seeds, especially under stressful environmental conditions. An additional merit of this technique is that it gives access to seeds with elevated moisture content. Various approaches may be employed to condition seeds after priming, but before redesiccation. Discarding the low-density fractions of primed tomato and lettuce seeds improved the percentage of germination compared with nonprimed seeds. Physiological mechanisms are presented to explain the association of density with seed viability in lettuce (Lactuca sativa L.).

Physiological, biochemical and ultrastructural aspects of imbibitional chilling injury in seeds: a review of work carried out at the Beijing Botanical Garden

AbstractThis paper is a résumé of research on imbibitional chilling injury of seeds. The following summarizes the experimental results obtained and some views and concepts derived from the studies conducted at Beijing Botanical Garden during the last decade. A lot of evidence has supported and confirmed the hypothesis for imbibitional chilling injury in seeds, i.e. the primary target of harmful effects during the chilling rehydration in seeds is the membrane systems, and the subsequent degree of lasting damage depends highly on the repair of the membrane systems themselves. The two processes of repair, physical and physiological–biochemical processes, can complement each other to a certain extent.

Soil Temperature Simulator for Seed Germination Studies

Conventional laboratory equipment used in seed germination research provides only constant and alternating temperature. The temperature of the soil in the seed bed is hardly ever constant or alternating in the same manner, but fluctuates constantly. In order to simulate the fluctuation of soil temperature that occurs in the field, a soil temperature simulator (STS) was designed, built, and evaluated. Plastic crispers containing soil in which seed are to be planted can be partially submerged in a rectangular tank into which water can be placed to a depth of 10 cm. Temperature of the water can be adjusted by heating and refrigeration systems under the control of a variable input programmer system. Maximum capabilities of the STS are: (i) maximum temperature drop 4 °C/h, (ii) maximum temperature rise 7.5 °C/h, and (iii) maximum temperature gradient within the unit 1.0 °C. The STS is capable of simulating fluctuations in soil temperature within a range of 4 to 40 °C and is particularly suited for the study of seed imbibitional chilling injury.

Seed coat permeability in semi-hard snap bean seeds: its influence on imbibitional chilling injury

SummaryThe susceptibility of a snap bean (Phaseolus vulgaris) breeding line with the semi-hard seed (SHS) characteristic to imbibitional chilling injury was studied. SHS with greater than 10% initial moisture content imbibed water readily. However, at 6% and 8% moisture levels 18 and 6 days were required for full imbibition, respectively. Seed coat permeability of SHS was readily reversible and was moderated by the seed storage relative humidity. Seeds of cv Bush Blue Lake 47 and cv Burly and SHS were adjusted to 12% moisture, and found to be tolerant to imbibitional chilling injury. At 8% moisture only SHS was not susceptible to chilling and this was attributed to slow hydration rates. Mechanical damage of SHS with 8% moisture resulted in increased hydration rates, solute leakage and chilling injury. An improvement in field seedling emergence was measured for SHS compared to the Bush Blue Lake 47 and Burly. SHS exhibited good field emergence at both 8% and 12% moisture.

Alleviation of Imbibitional Chilling Injury by Use of Lanolin1

Imbibitional chilling of seeds is generally associated with rapid entry of water in the cold. A means of alleviating chilling injury would be to retard the entry of water in the cold. Attempts to slow the rate of imbibition of soybean [Glycine max (L.) Merr.], corn (Zea mays L.) and cotton (Gossypium hirsutum L.) seeds through the application of a thin coat of lanolin (20 to 30 g kg−1 seed) provided alleviation of chilling injury in the chilling susceptible soybean and cotton.

ULTRASTRUCTURAL ASPECTS OF CHILLING INJURY IN THE SOYBEAN SEED RADICLE

Imbibitional chilling injury of soybean seeds was studied using light and electron microscopy. Intact seeds were allowed to take up water at 4 C or room temperatures and the ultrastructure of the radicle was examined after hydration. In chilled seeds, mitochondria showed weakly defined envelopes and cristae, in contrast to the well‐formed internal structure in the controls. Nuclei of chilled seeds were irregular in shape. Tannic acid was used as a probe of plasmalemma integrity. Most cells in both chilled and control treatments were able to exclude tannin, indicating that chilling injury effects did not damage the plasma membrane enough to allow passage of molecules of that size.

Ultrastructural Aspects of Chilling Injury in the Soybean Seed Radicle

Imbibitional chilling injury of soybean seeds was studied using light and electron microscopy. Intact seeds were allowed to take up water at 4 C or room temperatures and the ultrastructure of the radicle was examined after hydration. In chilled seeds, mitochondria showed weakly defined envelopes and cristae, in contrast to the well-formed internal structure in the controls. Nuclei of chilled seeds were irregular in shape. Tannic acid was used as a probe of plasmalemma integrity. Most cells in both chilled and control treatments were able to exclude tannin, indicating that chilling injury effects did not damage the plasma membrane enough to allow passage of molecules of that size.

Imbibitional Chilling Injury in Pollen

Chilling injury is sustained by dry pollen of Typha latifolia L. upon hydration in germination medium at 0 degrees C. This injury is evidenced as poor germination, low vigor, and depressed respiration. Isolated mitochondria showed multiple sites of impaired electron transport. Besides losses of cytochrome (Cyt) c and NAD(+), the activities of membrane-bound enzyme complexes such as Cyt oxidase, NADH-duroquinone oxidoreductase, succinate-duroquinone oxidoreductase, and malate-duroquinone oxidoreductase were severely affected.Similarly, as in isolated mitochondria, in situ tests of mitochondrial activity showed that Cyt c was partially lost from its site of action. Re-addition of the lost Cyt c to the grains restored the N,N,N',N'-tetramethyl p-phenylenediamine dihydrochloride plus ascorbate-mediated electron transport from Cyt c to O(2), but did not significantly accelerate the overall O(2) uptake. Electron flow to duroquinone in the injured grains was low, indicating that lesions at the substrate side of ubiquinone determine the rate of O(2) consumption. Leakage of NAD(+), and also of adenylate phosphates and Krebs cycle substrates out of the injured grains, was considerable.Increasing the initial moisture content of the grains strongly enhanced their resistance to cold hydration. Below 17% moisture content (fresh weight basis), the decrease in vigor closely matched the loss of NAD(+) and adenosine phosphates. Vitality was irreversibly lost by cold hydration below 10 to 12% initial moisture content.Injury to dry pollen was prevented by imbibition at 27 degrees C. Decrease of vigor and increased leakage, however, started below 20 degrees C, and complete loss of vitality occurred below 10 degrees C.These results are interpreted as evidence that loss of membrane integrity is the primary cause of imbibitional chilling injury.

Imbibitional Chilling Injury during Chickpea Germination

Abstract In the paper “Imbibitional Chilling Injury during Chickpea Germination” by Tony H.H. Chen, S.D.K. Yamamoto, L.V. Gusta, and A.E. Slinkard [J. Amer. Soc. Hort. Sci. 108(6):944–948, 1983], on page 946, Fig. 2 was omitted inadvertently during printing. The missing photograph and its caption appear below:

Imbibitional chilling injury in cultivars of soybeans differing in temperature sensitivity to pod formation and maturation periods

The occurrence and extent of chilling injury during imbibition of seeds from five cultivars and four lines of soybeans (Glycine max (L.) Merr) were tested. Seeds were imbibed and incubated at 2 °C for up to 72 h on moist filter papers and their ability to germinate when returned to 25 °C was recorded. Early-maturing varieties with the ability to form pods and seeds at lower temperatures were most susceptible to irreversible injury during imbibitional chilling. Rate of water uptake during low-temperature imbibition was measured, and seeds which were most susceptible to imbibitional chilling also had the highest rate of water uptake. In controlled-environment studies, seeds from the same cultivars that were set at different temperatures showed corresponding differences in susceptibility to imbibitional chilling injury. These results suggest that environmental temperatures during seed set or pod formation can play a role in chilling tolerance during seed imbibition.

Imbibitional Chilling Injury during Chickpea Germination

Abstract Either imbibition at low temperatures or fast water uptake reduced germination of chickpea (Cicer arietinum L.) by 15%. The combination of imbibition at low temperatures and fast water uptake reduced germination by 65%. The most chilling-sensitive period for chickpea germination is the first 30 minutes of imbibition. Slow imbibition at 20°C for 24 hours prior to seeding of mechanically damaged chickpea seeds significantly improved percentage of germination, and uniform, vigorous seedlings resulted. Such prehydrated seeds also showed better emergence under field conditions, especially in early spring when the soil was still cold. The results suggest that mechanically damaged seeds sown in cold, wet soil undergo imbibitional chilling injury and fast water uptake, leading to poor field emergence. Prehydration of seeds by slow imbibition at warm temperature and/or fungicide application increased the germination and emergence of chickpeas sown into cold, wet soils.