described by Fonteno et al. (2013) for determining the wettability of a substrate is known as the hydration efficiency test. In this method, known quantities of water are passed through a substrate and effluents are collected to determine the quantity of
Jeb S. Fields, William C. Fonteno and Brian E. Jackson
Christopher B. Cerveny, William B. Miller, Thomas Björkman and Neil S. Mattson
; Kamenetsky et al., 2005 ). It is common commercial practice to hydrate the dry roots before planting, because this provides handling uniformity and facilitates fungicide application (Y. Liberman, personal communication); however, the published information on
Cristian E. Loyola, John M. Dole and Rebecca Dunning
/night temperatures) compared with germination at 10/20 °C ( Torra et al., 2015 ). Postharvest issues on the farm. When considering all the postharvest issues, temperature management, hydration, and flower food management, and customer care of the product were the
Jabe E. Warren and Mark A. Bennett
Drum priming enhances seed performance without the waste and additional materials associated with conventional osmotic or matric priming techniques. Sweet corn (Zea mays L.) se (`White D' Lite') and sh2 (`WSS-4948') endosperm seeds were hydrated using drum priming at 25 °C for 6 hours. During each cycle, 125-g seed samples were exposed to 1.6, 3.2, 4.8, or 6.0 mL of distilled water and then rotated in a drum for 1 hour to ensure uniform uptake. At the end of this period, samples of 100 seeds (each) were removed and moisture content was determined. Drum priming hydrated all seedlots gradually, with increasing time required at reduced water levels for individual seedlots to achieve the desired moisture content (25% to 30%). Drum priming may provide a better alternative to conventional systems of priming.
A.G. Taylor, J. Prusinski, H.J. Hill and M.D. Dickson
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.).
Chris A. Martin, John M. Ruter, Robert W. Roberson and William P. Sharp
Hydration and elemental absorption of two commercially-available polyacrylamide gels (A and B) were studied in response to a 24-hr soak time in Hoagland's solution concentrations of either 2X, 1X, 0.5X, 0.25X, 0.125X or 0X (deionized water). Elemental absorption of gel specimens was observed and analyzed within the gel matrix on a Philips CM12S STEM equipped with an EDAX 9800 plus EDS unit for micro x-ray analysis. Thick sections were cut on dry glass knives using an RMC MT6000 ultramicrotome. Surface analysis of bulk specimens was made with an AMR 1000A SEM plus PGT1000 EDS unit. Overall, gel hydration decreased quadratically as solution concentration increased linearly; however, hydration for gel A was generally greater than for gel B. Surface analysis of gel samples revealed the presence Ca, K, P, S, Fe, and Zn for both gels. An analysis within the matrix of gel B revealed the presence of Ca, K, P, S, Fe, and Zn; however, an analysis within the matrix of gel A revealed the presence of Zn, and Fe only. The increased absorptive capacity of gel A appeared to be coupled to reduced migration of salts into the gel matrix.
Daniel C. Bowman and Richard Y. Evans
Hydration of a commercial hydrophilic polyacrylamide gel in 20 meq Ca(NO3)2/liter was reduced to <10% of the maximum hydration in deionized water. Repeated soaking with deionized water to remove soluble salts restored hydration to ≈ 30% of maximum. Incorporating KNO3 at concentrations ranging from 5 to 40 meq·liter-1 with the Ca(NO3)2 in the hydration solution partially reversed the Ca2+ inhibition of hydration following repeated soaking. Potential hydrogel hydration increased to 50% of maximum with 40 meq K+/liter. Potassium nitrate supplied separately following hydration in Ca(NO3)2 was much more effective at reversing Ca2+ inhibition of hydrogel hydration than joint application. Potential hydrogel hydration (following repeated soaking) was doubled after treatment with 5 meq KNO3/liter and reached 77% of maximum at 40 meq KNO3/liter.
Freshly harvested Rosa hybrida, `Kardinal' flowers were used to evaluate vase performance after hydration and storage at 37°F. Flowers were placed in one of six solutions for 24 hours and in dry storage for 3 additional days. After storage, half of the roses were cut before placement in vase solution containing 1% dextrose and potassium salts but without an anti-microbial agent.
Roses hydrated in aluminum sulfate had the shortest life followed by roses hydrated in CHRYSAL RVB. Flowers hydrated in CHRYSAL RVB and cut lasted as well as roses hydrated in HYDRAFLOR-100, 60 ppm sodium hypochlorite (naocl), citric acid, or citric acid with Tween 20 for one hour followed by 60 ppm maocl solution. Roses stored in naocl solution performed as well without, as with, cutting before placement in the vase solution. Results will be discussed in terms of microbe and particulate blockage of hydration pathways.
Jian Fana, E.E. Roos, C.W. Vertucci and F.D. Moore III
Seed water content has been considered the most important factor controlling various physiological reactions in seeds. Hydration/dehydration affects many physiological reactions, including the “priming effect” and “accelerated aging,” depending on time and level of hydration. Corn seeds (11% mc) were subjected to six cycles of hydration (2 h) and dryback or one hydration of 12 h and dryback. Following soaking, seeds were dried quickly by using a fan to remove moisture and then equilibrated to their initial mc. Seeds were evaluated for germination and vigor (root length and leachate conductivity). Percent germination of seeds treated with either continuous or intermittent hydration and dehydration was >90%. Vigor of seeds hydrated for successive 2-h cycles initially increased (priming effect); however, after the sixth cycle, vigor was equal to the nontreated control seeds. One cycle of hydration for 12 h then dryback had no effect on germination but did increase vigor. We are now extending the number of 2-h hydration periods to 10 to determine when damage occurs from these cycles. Our objective is to better understand the relationship between seed hydration and physiological changes associated with seed priming, accelerated aging, and imbibition damage.
Daniel C. Bowman, Richard Y. Evans and J.L. Paul
Hydration of three commercial hydrophilic polyacrylamide gels in deionized water ranged from 340 to 420 g per gram of gel. Hydration was progressively inhibited by fertilizer salt concentrations from 0 to 20 meq·liter-1. Hydration of the gels in the presence of divalent cations (Ca2+ and Mg2+) and monovalent cations (K+ and NH4 +) at 20 meq·liter-1 was reduced to ≈10% and 20% of maximum, respectively. The valence of the accompanying anion did not affect hydration. Gel hydration was unaffected by urea over the range of 2 to 20 mm. Sequential rinses of the hydrated gels with deionized water completely reversed the inhibition due to the monovalent, but not the divalent, cations. The electroconductivity (EC) of the external solution increased during gel hydration. In the presence of fertilizer salts, the physical properties of a 2 redwood sawdust : 1 sand (v/v) container mix were unaffected by hydrophilic gel additions of 1.2 and 2.4 kg·m-3 (1 × and 2 × the recommended rate, respectively).