Botanical Studies (2008) 49: 243-251.
*
Corresponding author:
E-mail: liyi2001@gmail.com.
INTRODUCTION
Today facing with the great loss of plant biodiversity
around the world, one way to protect is to store the plant
seeds in gene bank. The effective preservation of seeds de-
pends on their moisture content and the store temperature
(Hsu et al., 2000; Tsou and Mori, 2002), but in developing
countries where the costs of cold storage are prohibitive
(Zheng and Jing, 1998). Low moisture content conserva-
tion (it also called ultra-dry seed storage) through long-
term storage of seed is possible for a significant proportion
of higher plants. Where feasible, long-term seed storage
serves as a safe and relatively inexpensive method of plant
genetic resources conservation (Hong and Ellis, 1996).
Ultra-dry seed storage is a technique for decreasing the
seed moisture content to less than 5% and stored at ambi-
ent temperatures, it can reduce the cost for constructing
and maintaining the genebank and has brought worldwide
attention because of its potential economic effect and
promising application in germplasm conservation. A lot of
studies have been confirmed that ultra-dry seed storage not
only can be used to maintain the quality of seeds but also
improve the storability of seeds (Wang et al., 2003). Posi-
tive results of ultra-dry storage to improve storability have
been reported (Eills et al., 1989, 1990a, 1992, 1993, 1994,
1995; Cheng et al., 1991; Zheng and Jing, 1998; Wang et
al., 1999; Zhu et al., 2001; Huang et al., 2002; Wang et al.,
2005; Li et al., 2007).
Seeds during long-term storage at last lost their ability
to germinate. There are some papers have identified lipid
peroxidation, enzyme inactivation or protein degradation,
disruption of cellular membranes, and damage to genetic
integrity as major cause (Priestly, 1986; Smith and Berjak,
1995; Walters, 1998; McDonald, 1999; Narayana Murthy
et al., 2003). Under accelerated aging conditions such
as high temperature and high seed water moisture lead to
biochemical deterioration during seed aging (McDonald,
1999). In these cases, lipid peroxidation and the loss of
membrane phospholipids are major cause of seed aging
under accelerated aging conditions; the consequence of
A report on ultra-dry storage experiment of Zygophyllum
xanthoxylon seeds
Yi LI
1,
* , Jianjun QU
1
, Xiaoming YANG
2
, and Lizhe AN
3
1
Dunhuang Gobi and Desert Ecology and Environment Research Station, Cold and Arid Region Environmental and
Engineering Research Institute, Chinese Academy of Sciences, Lanzhou Gansu, 730000, P.R. China
2
Gansu Academy of Agricultural Sciences, Lanzhou Gansu, 730070, P.R. China
3
School of Life Science, Lanzhou University, Lanzhou Gansu, 730000, P.R. China
(Received September 21, 2007; Accepted March 11, 2008)
ABSTRACT.
This research aimed to determine whether ultra-dry storage improves the longevity of
Zygophyllum xanthoxylon seeds. Moisture content of Z. xanthoxylon seeds was dried to 4.81%, 3.81%, 2.41%
and 1.99% (w.b.) in a desiccating container with silica gel, and stored at 45¢XC, 25¢XC and 15¢XC for 24 months.
The data from 24 months showed that the optimum moisture content for storage varies with temperature.
Our results found that optimum moisture can not be considered independently of temperature. After ultra-
drying the seeds were accelerated aged (50¢XC, 1 month), some physiological indices were tested. The results
indicated that Dehydrogenase, POD, SOD and CAT activities of the ultra-dry seeds were higher than those
of the control seeds, while volatile aldehydes and malondialdehyde were lower than the control group. The
results indicate that moisture content of seed was a key index for storage at ambient temperature (25¢XC) and
3.81% seem to be the best moisture content for ultra-dry seeds in our research. RAPD markers were also used
to evaluate the genetic fidelity of seeds, all RAPD profiles from ultra-dry seeds were monomorphic and similar
to non-ultra-dry seeds, we conclude that variation is almost absent in ultra-dry storage. From these results, we
suggest that seed moisture content less than 5% enhances longevity and ultra-dry could be an economical way
for conservation of the plant genetic resource.
Keywords: Moisture content; Physiological indices; RAPD; Seed storage; Ultra-dry; Zygophyllum
xanthoxylon.
PHYSIOLOGY