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mainly distributed 71 <strong>to</strong> 72 percentage, taking up 50
percentage in F 2:3 population. In F 2:3 population, <strong>the</strong> starch
content over 73 percentage <strong>to</strong>ok up 1.4 percentage <strong>and</strong>
below 69 percentage <strong>to</strong>ok up 0.7 percentage. It explained
that <strong>the</strong> starch content in F 2:3 population was concentratly
distributed. In general, different nutritional qualities
distribute continuously.
334 pairs of maize SSR primers were used <strong>to</strong> detect <strong>the</strong>
polymorphism in parents LX00‐6 <strong>and</strong> E28, of which 25
pairs of polymorphism primers were obtained.
Connecting with <strong>the</strong> information or known primers, <strong>the</strong>
genetic linkage map had been established using
MAPMAKER/EXP 3.0, in which <strong>the</strong> markers on <strong>the</strong>
1 st ,2 nd ,5 th ,6 th ,8 th <strong>and</strong> 10 th chromosome. The genetic
linkage map covered 124 loci <strong>and</strong> spanned maize genome
about 1497cM, with an average interval of 12.07 cM.
Based on <strong>the</strong> linkage map <strong>and</strong> nutritional quality detected,
3 QTLs controlling nutritional quality traits were
identified by using QTL composite interval mapping. We
mapped 1 QTL associated with oil locating on <strong>the</strong> 1 st
chromosome <strong>and</strong> demonstrating additive effect. 2 QTLs
associated with starch were located on <strong>the</strong> 1 st <strong>and</strong> 8 th
chromosome <strong>and</strong> demonstrated partial dominance effect.
But we found no QTLs associating with protein content.
More SSR primers are being used <strong>to</strong> detect <strong>the</strong>
polymorphism in parents, <strong>the</strong> high‐resolution genetic
map will be obtained <strong>and</strong> more QTLs will be found.
Research on soil infiltration law of different
l<strong>and</strong>ues types in Jinsha River dry­hot valley
Zhiqin LIU
Southwest Foresty University.Email: lzq‐xl@163.com
This article takes 4 different slope l<strong>and</strong>s(arbor forest,
shrub l<strong>and</strong>, grassl<strong>and</strong> <strong>and</strong> wastel<strong>and</strong>) of Laocheng village
as <strong>the</strong> experimental points in Jinsha River dry‐hot volley.
The advanced double‐rings method is adopted <strong>to</strong> illustrate
<strong>the</strong> rules of soil moisture infiltration characteristics in
four different l<strong>and</strong>use types. The results show that <strong>the</strong>
physical properties <strong>and</strong> structure of forestl<strong>and</strong> are better
than those of non‐forest l<strong>and</strong>; different l<strong>and</strong>use types have
obvious differences in soil infiltration capability among
four different patterns of l<strong>and</strong>use. Arbor forest behaved
<strong>the</strong> best infiltration capability <strong>and</strong> wastel<strong>and</strong> <strong>the</strong> worst;
<strong>the</strong> average infiltration <strong>and</strong> <strong>the</strong> steadily infiltration attains
1.67mm/min <strong>and</strong> 0.5mm/min respectively during <strong>the</strong>
first 120min of soil water infiltration process in arbor
forest. The rate of whatever <strong>the</strong> average infiltration or <strong>the</strong>
steadily infiltration express <strong>the</strong> same regulation. The
arbor forest is slightly higher than <strong>the</strong> shrub l<strong>and</strong>, <strong>the</strong>
grassl<strong>and</strong> <strong>and</strong> <strong>the</strong> waste l<strong>and</strong>. The moisture infiltration
rate in different l<strong>and</strong>use types can all be thoroughly
defined through <strong>the</strong> Hor<strong>to</strong>n equation. Water infiltration is
affected by <strong>the</strong> bulk density of <strong>the</strong> soil. With <strong>the</strong> bulk
density increasing, <strong>the</strong> steady infiltration rate decreases
<strong>and</strong> <strong>the</strong> two are at an exponential function.
Studies on mutation breeding <strong>and</strong>
mechanism of isomannanase producing
strain by UV light
Liping WANG <strong>and</strong> Zhaoyan MU
Shanghai Ocean University, Shanghai, China.
Mannan oligosaccharides (MOS), which can stimulate <strong>the</strong>
growth of bifidobacteria selectively, are a kind of
prebiotics <strong>and</strong> ideal feed additives. MOS can be obtained
by hydrolyzing mannana with isomannanase <strong>and</strong>
improving <strong>the</strong> activity of mannanase is one of <strong>the</strong> key
fac<strong>to</strong>rs for <strong>the</strong> efficient production of MOS. To improve
<strong>the</strong> activity of isomannanase, a Bacillus subtilis K‐6 strain
secreting isomannanase preserved in our labora<strong>to</strong>ry was
induced mutated, <strong>the</strong> solid‐state fermentation conditions
of a positive mutant B. subtilis K‐6‐9 was optimize, <strong>and</strong>
mechanism of mutation of K‐6‐9 was analyzed by
bioinfonnatics methods.
The results showed that treated with ultraviolet (UV) light,
mutations of K‐6 were produced, <strong>and</strong> <strong>the</strong> enzyme activity
of <strong>the</strong> obtained highest‐yielding mutant K‐6‐9 reached up
<strong>to</strong> 348.2 U/mL, which was 169.1% higher than <strong>the</strong>
enzyme activity of K‐6. The results of 5 sub‐cultures
showed that <strong>the</strong> enzyme activity of K‐6‐9 were between
342.9 U/mL <strong>and</strong> 349.5 U/mL, indicating <strong>the</strong> mutant is
stable.
In addition, <strong>the</strong> optimal condition of solid‐state
fermentation for production of enzyme was studied by
single fac<strong>to</strong>r experiment <strong>and</strong> orthogonal experiment with
K‐6‐9. The results showed that <strong>the</strong> optimized medium
formulation for enzyme producing were wheat bran 40%,
yeast cell 8%, NH 4 Cl 1.5%, <strong>and</strong> ratio of material <strong>and</strong>
water 1:1.2, <strong>and</strong> <strong>the</strong> optimal culture conditions were
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