Carleton 1968
Carleton 1968
Carleton 1968
Northern Rocky Mountain region. In preliminary Speed of elongation was calculated by the formula:
testing the variety ’Eski’ appears to be adapted as a
range legume to areas with 13 or more inches of SE = mean seedling length -b ....
~-~ to first count
precipitation. Hay yields of sainfoin were similar to
alfalfa in short-term irrigated hay trials in two-cut mean increase in length from previous count’~
areas (1). Sainfoin yielded more than alfalfa in
area where short water supply limited production to
days to last count )
The effect of temperature and of the pod on speed
one cutting (1). Sainfoin is not knownto cause bloat.’ of germination is shown in Fig. 1. Germination of
Potential for bloat is similar to birdsfoot trefoil (Lotus shelled seed was most rapid at 20 C. The next most
corniculatus L.) based on in vitro foam formation of rapid germination temperature was 15 C. Rapidity
extracts from each species (2). of germination of shelled seed decreased as tempera-
Since sainfoin has not been investigated extensive-
ly in the United States, information is needed concern-
ing its culture. The present study is concerned with the 55-
effect of the seed pod and temperature upon germina-
tion and seedling elongation. Sainfoin seed matures in
one-seeded pods, described by Piper (7) as "brown, 5O
indehiscent, lenticular, and reticulated on the sur-
face." The pod is bean-shaped and bilaterally com-
pressed, and it has a rough net-veined appearance. The 25
~eed itself is kidney-shaped, varying from yellowish
green to dark brown in color. The seed is much
larger than seed of our commonforage legumes. A ~o
pound of seed in the pod contains about 18,800 seeds
and a pound of shelled seed about 26,500 seeds (4).
Thus, the pod comprises 29% of the seed weight.
The effect of the pod upon germination was pre-
viously studied by Thomson (8). He concluded that I0,
lower germination was due to the failure of the radi-
cle from weaker seed to penetrate the pod. He also .5-
z Cooperative investigations of the Montana Agricultural Ex-
periment Station and the Crops Research Division, Agricultural
Research Service, USDA.Published with the approval of the
¯ Director of the Montana Agr. Exp. Sta. as Journal Series 814.
Received June 6, 1967. GERMINATION TEMPERATURE (,C)
~Assistant Professor; Agronomist, Crops Res. Div., ARS, USDA;
and Seed Analyst, Montana State Univ., Bozeman, Mont., re- Fig. l. Effect of germination temperature and seed condition
spectively. on speed of germination.
81
82 AGRONOMYJOURNAL, VOL. 60, JANUARY-FEBRUARY 1968
tures increased above 20 C. Germination of seed in Effect of Pod on Rate of Water Absorption
the pod was similar at a range of 15 to 23 C and de- Replicated 100-seed lots of shelled and unshelled sainfoin
creased at 30 and 35 C. At all temperatures, seed seed were germinated at 20 C. The germination procedure was
in the pod was slower to germinate than shelled seed. the same as in the previous study. At 20-minute intervals for
At the end of 8 days total germination of both shelled the first hour, and 1-hour intervals the next 15 hr, replicates
and unshelled seed was less at 30 and 35 C (Fig. 2). of each seed type were relnoved. Pods were re~noved from un-
shelled seed and the amount of moisture absorbed by each seed
Total germination of shelled seed was greater than un- type was determined.
shelled at all temperatures. This difference may have Water absorption by shelled seed was very rapid
been due to a difference in seed quality. Immature (Fig. 5). After 4 to 5 hr the water content rose
seeds were readily detected and removed from shelled between 50 and 55%, where it remained for the dura-
seed but could not be detected in seed in the pod. tion. of the test. In contrast, water content of seed in
Temperature optimums for seedling growth were the pod did not approach that of shelled seed until 9
.different from those for germination (Fig. 3). Optimnm to 10 hr. The differences of 4 to 5 hr in the time
temperatures for speed of seedling elongation ranged needed to reach maximumabsorption is not likely to
from 20 to 30 C for shelled and from 15 to 30 C for be of much importance, given adequate water for
seed in the pod. At all temperatures, speed of seedling germination. However, with summer showers and
elongation of Shelled seed was more rapid. Conse- rapid drying, this lag might be enough to prevent seed
quently, total seedling length at 8 days was general- from germinating at a time when seedbed moisture
ly greater for seedlings from shelled seed (Fig. 4). is not adequate to sustain the seedlings.
The decrease in speed of germination and of seed-
ling elongation caused by the pod (Fig. 1 and 3)
could be due to several factors; namely, (1) a slowed IOO-
rate of water absorbtion, (2) the presence of an in-
hibitor, and (3) mechanical restriction. These factors
were studied in .subsequent experiments. 90-
80’
IOO-
HEL
~ SHEL LED g ~’o-
90- "i-
I--
o 60-
o 50-
~ 70- Z
tu _J
~ 40-
~ 6o-
IN THE POD
~0-
50-
20-
40-
15 20 23 30 35
15 20 23 30 35 GERMINATION TEMPERATURE(C)
GERMINATION TEMPERATURE(C)
Fig. 4. Effect of germination temperature and seed condition
Fig. 2. Effect of germination temperature and seed condition upon seedling length after 8 days.
on percent germination after 8 days.
z 25
z ~ 40 /N THE
o
.J ~-35-
"~ 15
r~ I0
o 20-~
uJ
,, 5
0 l=.+si=_+ 1.8 IO-
uJ 0 I I I I
Q. 0 I I I I I I I I I I I I I I I
u) 15 20 23 30 35
GEI~IMINATION TEMPERATURE (C) H~ IN ~EOMIN&TO~
Fig. 3. Effect of germination temperature and seed condition
on speed of seedling elongation. ¯ ig. ~. Water uptake of shelled and ~sheIled sa~fo~ seed.
CARLETON ET AL.: GERMINATION OF SAINFOIN 83
described.
and
~ ~o
~ 50 ,,.///
The addition of the water extract from the sain-
~ ~o. .
loin pods slowed rate of germination. Speed of germi-
nation (SG) of shelled seed, shelled seed with extract
added, and seed in the pod was 70.1, 50.1 and 28.9,
respectively. These values were significfintly dif- , , , ,
ferent. The addition of the extract did not slow 12 24 36 48 60 72 84 96 108 120 132
germination to the rate observed for seed in the pod. HR IN GERMINATOR
This was probably due to a dilution effect from spread- ¯ i~. 6. ]nflucn~c o[ ~our sec~ trea~ents ~pon germina~o~ ~ate
ing the extract over the total blotter surface in the o~ sMn~oin.
germinating dish.
In a second study, a sample of unshelled sainfoin seed was
soaked in water for 18 hr and then air-dried for 7 days. The I00-
sample was then divided and one-half was soaked a second time
for 18 hr and dried for 7 days. Replicated seed lots from these
two samples were germinated in comparison with unsoaked 90-
shelled and unsoaked, unshelled seed.
Soaking seed did not reduce total germination 80-
(Table 1). Seed in the pod soaked twice germinated
more rapidly than unsoaked unshelled seed (Table 70-
1). Germination appeared to be faster for seed soaked
twice than for seed soaked once although the differ- ’1- 60-
ence was not significant. Seed in the pod soaked twice I--
germinated as rapidly as shelled seed. These data sug- Z
gest the presence of a water-soluble germination in- 50-
hibitor in the sainfoin seed pod.
A third study was conducted in which sainfoin seed was sub- 40-
jected to the following four treatments: (1) pods removed; (2)
pods opened but left on seed; (3) pods opened, removed from
seed, washed for 16 hr, oven-dried, and replaced on seed; and 30-
(4) seeds left undisturbed in the pods. Eight replications of
100 seeds each were used for each treatment. After treatment, 20-
seed lots were placed in 4 X 4-inch plastic trays on blotter
paper, moistened with 30 ml distilled water and germinated at
20 C. The percentage germination was determined at 12-hr in- I0-
tervals over a 132-hour period.