Richmond planet. [volume] (Richmond, Va.) 1883-1938, 1905-02-11

= lS. I-Slelt 1raIIflg. Z-Bud Graft.
union is generally understood to deter
mine the whole success or failure of the
graft. These phrases, good unions and
poor unions, are common in horticulture,
yet their significance is generally un-
known. The facts are often wrongly
guessed and the whole nature of the mat
ter at times essentially misunderstood.
1t is pointed out by Prof. Waugh that
in herbaceous grating (where soft
growing parts are sed) there is no gem
'eral commingling of the cells of scion
and stock as has been popularity imag-
tned. The original scion and the origin
al stock remain to the end of their ex-
istence very largely separate and dis
tinct. Disregarding for a moment the
very thin cambium zone. the stock and
scion are made up wholly of dead wood
and bark. With perfectly negligible ex-
cepuons the cells are all dead, totally
and forever. II is absolutely impossible
Tor them to grow or TO unite with any
thlng. One might as well talk of MAX
tng lead pencil unite with a penholder
or a neckyoke with a singletree. The
two may be glued together, waxed to-
unite
The thin sheet of cambium. lying be-
tween the bark and the wood, is the only
portion OF the tree stem which is really
alive, the oD'y portion which can grow
and is therefore the part where we must
look for the beginning of the graft union.
Note Fig. l, which is diagram of a cleft
graft three years old. The black por-
lions represent the wood of the original
scion and stock; the white portions
three annual layers of wood which have
grown since the graft was made.
II mas long been the dream of gar
oeners to produce new kinds of plants
by the graft union of new scions and
stocks. Our present observations show
this to be impossible No matter how
closely the two kinds of cells may lie
against one another, their contents are
never mingled in the production of the
cell. The cell tissues of the stock and
scion may comminele or lap in together
somewhat in the line of union. but this
mixture is only mechanical. not physio-
logical. The experiments were con-
Quoted with bud unions, and from orr
view there is no difference between p
oud graft and long scion graft.
Fig 2 shows diagramaticallv tba
growth of a bud when set upon a stock
The black portion represents the wood
or the stock, the shaded portion the bud
or scion and the white portion three on
huai layers OF growth which have been
put on since the bud was set In this
case, as with the common graft. the law
ers OF the new growth are continuous.
running from top to bottom without any
break at the plane of junction.
IL the normal union of scion and stock
is made OF such complete and continuous
cylinders OF annual growth as above
mentioned, one will naturally ask the
reasons Tor the unsuccessful unions. The
answer is not an altogether easy one
we may approach ii by saying that
when the two members are unlike ina
ture and in some way physioloeicallv in
compatible, the wood does not heal read
lly, owing TO some sort Of irrigation
winch continues to be felt at this point.
After a close study of large number
OF defective scions, Prof Waugh has
reached the opinion that they are all
most always due to this incompatibilitv
OF stock and scion.
1t is common notion among horti-
culturists that careless or ignorant man
tpulation in the grating will lead TO
poor unions. There seems to be LITTLE
ground for this opinion. If the stock and
scion are of varieties which are congen-
ial, and If the graft or bud grows at all.
the union will nearly always be good.
Poor manipulation will often cause the
failure of a large percentage to grow.
but 1t seldom affects permanently the
strength of The uI.icn in those c-2s.-