108 W. Q. Zheng et al.
After one day of larval rearing medium treat-
ment by CC, the substrates were in the condi-
tion of compaction, appearing rigid and turning
gray. Compaction is the process of compacting
materials. It means to compress, condense or
consolidate. Severe compaction reduces materi-
als’ pore space, thereby increasing bulk density,
expressed as grams per cubic centimeter (g/cm^3 )
(Horn et al. 1995 ). In soil, compaction has impact
on microorganisms, growth of plant and soil ani-
mal, just because soil compaction induces sever-
al stresses which negatively influences physical
properties of soil (bulk density and pore space)
and may interact simultaneously, including in-
creased soil strength, decreased aeration and re-
duced hydraulic conductivity (Tracy et al. 2011 ).
Therefore, soil compaction may consequently
limit soil microfungi, which are significant for
nutrient bioavailability. Non-normal microbe
population further heads off plant and soil ani-
mal development (Kara and Bolat 2007 ). These
problems such as aeration decrease and hydrau-
lic conductivity shrinkage demonstrated in soil
compaction may happen in larval rearing me-
dium. Larval rearing medium compaction due to
chemical or physical reaction after CC addition
can have profound effects on water communica-
tion and air exchange and, hence, can have a det-
rimental effect on maggots’ normal metabolism.
We performed a study to observe the effect of
different CC concentrations on larval rearing me-
dium compaction. The effect was predominantly
obvious, higher concentration CC having heavier
compaction compared with the lower concentra-
tion counterpart. Our observed results indicated
some negative effects of larval rearing medium
compaction focusing on minimizing water and
air exchange between medium and maggots, and
then heading off normal metabolism, inducing
maggots mortality at last. Compared to null mag-
gots in control group, approximately one third of
the whole maggots sneaked up on side wall of the
beakers in treatment counterpart. This phenom-
enon strongly and further confirms decrease in
aeration and hydraulic conductivity shrinkage in
larval rearing medium after its compaction.
CC and its break-down products hydrogen cy-
anamide (HC) exhibit some bioactivity to other
organisms involving fungi, mollusk and nema-
tode. The mode of action of CC or HC on kinds
of plants has extensively been exposed. HC stim-
ulates the fermentative pathway, inhibits respira-
tion to release buds from dormancy and restricts
plant growth (Vergara et al. 2012 ). The bud re-
sponse to HC is showed, more condensed and
stronger, as reflected by a higher number of regu-
lated genes and a higher intensity of regulation.
HC perturbed mitochondrial activity, developed
oxidative stress and established a situation that
resembled hypoxia (Ophir et al. 2009 ). Oxidative
stress or hypoxia induced expression of Ca2+-
ATPase and then evoked an increase in [Ca2+]cyt.
Similar induction was confirmed for calmodulin,
calmodulin-binding protein, and calcium-depen-
dent protein kinase (CDPK). HC induced-mech-
anism of Ca2+ signaling led to release of bud dor-
mancy. HC also changed the interplay between
abscisic acid (ABA) and ethylene metabolism. It
temporarily caused an increase of acetaldehyde,
ethanol and ethylene which enhanced bud break
(Ophir et al. 2009 ). Most genes identified fol-
lowing HC application appeared to be associated
with the reactivation of growth. Groups of genes
that were rapidly up-regulated in response to HC
were the glutathione S-transferase (GST) class
of genes. Phylogenetic analysis of these GSTs
showed that they clustered into sub-clades, sug-
gesting a strongly correlation between their ex-
pression and bud-break across species (Walton
et al. 2009 ). HC also induced early bud break
and at the same time down-regulated PpDAM5
and PpDAM6 expression, two of the six peach
( Prunus persica) dormancy-associated MADS-
box genes (Yamane et al. 2011 ). In the short term,
HC induced transiently the expression of hypox-
ic responsive genes (HRG) and flowering locus
T(VvFT), a transcription factor related to dor-
mancy release in Vitis, and hastened the sprout-
ing of endodormant grapevine-buds. In the long
term, along with the advancement of bud-break,
the expression of these genes moved forward in
treated buds, suggesting that this second induc-
tion that occurred just before bud-break was de-
velopmentally regulated (Vergara et al. 2012 ). On
the other hand, HC restricted growth of plant in
a dose-dependent manner. Cytological observa-