effect of artificial media, temperature conditions and
TRANSCRIPT
Jpn. J. Trop. Agr. 50(1): 51-56, 2006
Effect of Artificial Media, Temperature Conditions and Storage Methods on in vitro Germination of Dragon Fruit
(Hylocereus undatus Britt & Rose) Pollen
Mustad Malid MACHA1, Abul Kashem CHOWDHURY2, Tatsuro MURATA3 and Yoshimi YONEMOTO4*
1 Faculty of Agriculture, Sokoine University of Agriculture, Tanzania2 Faculty of Genetics and Plant Breeding, Patuakhali Science and Technology University, Bangladesh3 School of Agriculture, Kyushu Tokai University4 Tropical Fruit Laboratory, Okinawa Subtropical Station, Japan International Research Center for Agricultural Sciences
Abstract White fresh dragon fruit (synonym: pitaya) (WD) is self compatible, while the Red fresh dragon fruit (RD) cultivars
are incompatible. Therefore, RD cultivars require artificial pollination with pollen from other cultivars to set fruit. The objective
of the present study was to identify suitable conditions for pollen germination of WD cultivars as a pollinator, using artificial
media at various sugar concentrations and various temperatures. Also various pollen storage methods were evaluated .
The use of agar containing 30% sucrose led to the highest values for the percentage of pollen germination and tube
elongation. The percentage of pollen germination was reduced at concentrations below 20% and above 40%, and the pollen did
not germinate at in the absence of sucrose and at a 50% sucrose concentration. Although the highest germination percentage
was observed at 30, 35 and 40•Ž, the germination percentage decreased at temperatures above 45•Ž and below 25•Ž . Pollen
germination did not occur at 10 and 55•Ž. Pollen germination percentage of fresh pollen and fresh pollen stored for 20 hrs
without silica gel exceeded 30%. However, pollen germination did not occur after storage under dry conditions with silica gel at
5•Ž. Pollen germination and tube elongation were reduced after storage at -20 and -30•Ž for 15 days. Pollen did not germinate
after being stored in acetone and ethyl acetate. Pollen stored in a sucrose solution (from 20% to 60% w/v) remained viable for 3
days, while pollen germination did not occur after pollen was stored in the absence of sucrose or in 5 and 10% sucrose solutions.
It was concluded that the use of sucrose at 30% concentration at 30, 35, and 40•Ž was suitable for pollen germination and tube
elongation, while prevention of exposure of pollen to dry or too wet conditions is necessary for pollen storage of dragon fruit .
Key Words: Agar medium, Incubation temperature, Pollen storage, Pitaya, Pollen viability, Sucrose concentration.
Introduction
Hylocereus undatus Britt & Rose (syn. Cereus
undatus Haw.) is called strawberry pear (Morton,
1987) or Dragon Fruit (Ke, 1997; Karp, 2003) in
English. The Spanish terms pitaya, pitajaya, pitahaya,
are used for the strawberry pear in Latin America
(Morton, 1987). These plants are climbing cacti native
to the tropical forests of the northern part of South
America, Central America and Mexico (Karp, 2003).
The major producers are Vietnam and Taiwan. The
plants were introduced into Japan a few years ago
(Nomura et al., 2005). The production of dragon fruit
in Okinawa Prefecture has also increased over the last
years (Yamamoto et al., 2004). The fruit could become a profitable new crop, therefore drawing more farmers
into its production. The plants are grown in the open in
tropical areas, but must be protected from intense
solar radiation and subfreezing temperatures when
cultivated under subtropical conditions such as those
prevailing in Israel (Mizrahi et al., 1997; Raveh et al.,
1997). There are three species of dragon fruit in
Okinawa; red-skinned with white flesh (WD), red-
skinned with red flesh (RD), and yellow-skinned with
white flesh (VI)). Generally among these three kinds
of cultivars, WD and YD are self compatible, while the
RD cultivars are incompatible. Therefore RD cultivars
require artificial pollination with pollen from other
cultivars to set fruit. Unfortunately, these cultivars
sometimes bloom at different times, i.e, with one to
two-week differences, leading to the absence of or very
little pollination. As a result, very small fruits which
fetch a low market value are produced. Furthermore,
in order to increase the fruit size, it is important to use
pollen with a high germination percentage. It is, therefore, necessary to develop an appropriate method
of pollen storage over a long period of time without
loss of viability. In addition, it is also important to
determine the optimum temperature for pollen
germination to obtain a higher fertilization rate.
Received Oct. 13, 2005Accepted Dec. 10, 2005* Corresponding author
Ishigaki, Okinawa 9070002, [email protected]
52 Jpn. J. Trop. Agr. 50 (1) 2006
Therefore, it is necessary to identify suitable conditions
for WD pollen storage for artificial pollination of RD
cultivars at anthesis, especially when WD blooms at
different times from RD. However, the number of
studies on pollen storage or conditions of pollen
germination for dragon fruit is very limited.
The objectives of the present study were to
identify suitable conditions for pollen germination,
using artificial media at various sugar concentrations
and temperatures for dragon fruit, and to develop a
suitable method for pollen storage over a long period
of time.
Materials and Methods
Sugar content in artificial media and incubation
temperature
WD cultivars grown at the Japan International
Research Center for Agricultural Sciences (JIRCAS)
Okinawa Subtropical Station in Ishigaki were investigated.
Fresh anthers and pollen grains were collected from 5
blooming flowers at 7.00am on June 26, 2005. The
pollen grains were then separated from the anthers by
shaking them in a sieve and they were mixed well.
Two percent agar lacking sucrose or containing 5, 10,
20, 30, 40, 50 and 60% (w/v) sucrose and 500ppm boric
acid was prepared. For each concentration, lml of agar
was dropped on 6 glass slides on which the fresh
pollen grains were poured using a small brush. The
glass slides were arranged in small plastic containers
with moist tissue paper on the underside, then covered
on top and kept at 25 •Ž. Observations of pollen
germination and tube elongation were performed
using a microscope (100 X ) at 20 hrs after plating of
the pollen. The germination percentage and tube
elongation were calculated by the method of Yonemoto
and Hennayake (2002).
Based on previous experimental results, we
prepared 2% agar containing 30% sucrose and 500ppm
boric acid. The fresh pollen was collected in the same
way as that described above on June 28, 2005. The
pollen was poured on the media and incubated at 10,
15, 20, 25, 30, 35, 40, 45, 50 and 55•Ž. Observations of
pollen germination and tube elongation were performed
at 20hrs after plating of the pollen.
Effect of storage methods on pollen germination
and tube elongation
The pollen of the WD cultivars was collected at
7.00am on the July 3, 2005 from 5 blooming flowers.
The pollen was separated from the anthers, as
described in the previous experiment. Seven different
methods were used as follows: Fresh pollen (soon after
collection); Fresh pollen without silica gel stored in
22m1 vials for 20hrs; Fresh pollen with 2g silica gel
stored in 22m1 vials for 20hrs; Fresh pollen stored at -20
•Ž and -30 •Ž for 15 days; Fresh pollen stored in 95%
acetone and 95% ethyl acetate for 20 hrs. For the
storage in organic solvent, 0.lg of pollen was dissolved
in 5m1 of each organic solvent and stored at 5©C for 20
hrs. The pollen grains were filtered with a filter paper
and air-dried at room temperature for 10 minutes
before being plated. For storage under freezing
temperature, 0.lg of pollen was wrapped with a powder
paper, and sealed in a vial and stored at -20 or -30•Ž for
15 days. Pollen was plated on 2% (w/v) agar media
containing 30% (w/v) sucrose and 500ppm boric acid.
Pollen germination percentage and tube elongation
were determined after 20hrs of incubation at 30 •Ž on
the media. Germination percentage and tube elonga-
tion were calculated by the method of Yonemoto and
Hennayake (2002).
In addition, pollen storage in a sucrose solution at
5 •Ž was examined. A 0.lg aliquot of pollen was
dissolved in 5m1 of a solution lacking sucrose or in 5ml
of 5, 10, 20, 30, 40, 50 and 60% (w/v) sucrose water
solutions and stored at 5 •Ž for 1, 3, 5, 10, 15 and 20
days. Pollen solutions were dropped using an injector
on agar media, as described above. Germination
percentage and tube elongation were determined after
20hrs of incubation at 30 •Ž on the media. The
observation methods were the same as those used in
previous experiments.
Storage of fresh pollen in a vial at 5 •Žwas
examined on the July 4. A 0.lg aliquot of fresh pollen
was wrapped with a powder paper. Fourteen wrapped
pollen were sealed in a vial and stored at 5 •Ž. Pollen
viability and tube elongation were determined every
day up to 10 days and every 5 days up to 25 days.
Observation method was the same as that used in
previous experiments.
Results and Discussion
Sugar content in artificial media and incubation
temperature
The diameter of the germinated pollen grains of
dragon fruit was about 150 ƒÊ m (Fig. 1). Sugar content
in artificial medium affected the pollen germination
percentage and tube elongation (Table 1) . The use of
agar containing 30% of sucrose led to the highest
percentage of pollen germination percentage (signifi-
Macha et al.: Dragon fruit pollen germination 53
Fig. 1 Germinated pollen grains of dragon fruit (Hylocereus
undatus Britt & Rose) 20 firs. after planting of
pollen on a germination medium containing 2% agar, 30% sucrose and 500ppm boric acid.
cant difference at p<0.01 by Tukey's method). Pollen
did not germinate in agar lacking sucrose or containing
50% sucrose. Pollen viability was reduced dramatically
at concentrations of more than 40% but also of less than
20%; consequently the tube length was reduced at 40%.
The optimum sucrose concentration in the agar medium
for pollen germination was in the range of 5-10% for
white sapote (Yonemoto et al., 2000), 5-15% for kiwi
(Watanabe and Takahashi, 1989), 10-20% for cherimoya
(Yonemoto et al., 1999), 25% for mango (Popenoe,
1917), 30% for purple passionfruit (Ishihata, 1983). Our
results indicated that the optimum sucrose concentra-
tion for pollen germination for the dragon fruit was the
same as that for the purple passionfruit.
Incubation temperature significantly affected (p<0.05
Tukey's method) the pollen germination percentage
and tube elongation (Table 2). The highest values for
the germination percentage and tube elongation were
observed at 30, 35 and 40 •Ž, and decreased at
temperatures above 45 •Ž and below 25 •Ž. Pollen
germination was not observed at 10 and 55 •Ž. The
optimum temperature for pollen germination was 25 •Ž
for lemon (Ganeshan and Alexander, 1991) and avocado
(Loupassaki et al., 1997), 25-30 •Ž for kiwi fruit
(Watanabe and Takahashi, 1989), cherimoya (Yonemoto
et al., 1999) and white sapote (Yonemoto et al., 2000).
The optimum temperature for pollen germination for
the dragon fruit was much higher than that for these
fruits. Dragon fruit blooms from June to October in
Okinawa Prefecture. Minimum temperature during
this period is higher than 25 •Ž, at which the pollen
germination percentage decreased to 25.5%. However,
this germination percentage seems to be high enough
for a normal fruit set, because artificial pollination was
very successful in commercial cultivation in Okinawa.
Due to the high prices fetched during the winter
period, farmers aim at producing the dragon fruit
during that period, by applying supplemental light.
Although flowering can be induced in winter by the
application of supplemental light, the low temperature
will, however, result in low pollen germination.
Therefore, the dragon fruit should be grown in a
plastic house to raise the air temperature for winter
production.
Table 1 Effect of sucrose concentration in growth media
on pollen germination percentage and pollen tube
elongation in pitaya
Different letters indicate statistical significance by Tukey's
method at p<0.01.
The media contained 2% agar (w/v) and 500ppm boric and were
incubated at 25 •Ž.
Measurements were performed at 20hrs. after plating of pollen
on the media.
One hundred pollen grains were observed six times.
Fresh pollen was collected at 7:00 am on June 16, 2005.
Table 2 Effect of incubation temperature on pollen
germination percentage and pollen tube elongation
in pitaya
Different letters indicate statistical significance by Tukey's test at p<0.05.
The media contained 2% agar (w/v) 30% sucrose (w/v) and 500ppm boric acid.
Measurements were performed at 20hrs. after plating of pollen
on the media.One hundred pollen grains were observed in six times.
Fresh pollen was collected at 7:00 am on June 25, 2005.
54 Jpn. J. Trop. Agr. 50 (1) 2006
Effect of storage methods on pollen germination
percentage and tube elongation
Storage methods affected the pollen germination
percentage and tube elongation (Table 3). The highest
germination percentage was observed with fresh
pollen soon after collection and fresh pollen stored
without silica gel for 20 hrs. Pollen stored in 95%
acetone or 95% ethyl acetate and pollen stored with
silica gel did not germinate. These results indicate that
the dragon fruit pollen loses its viability under dry
conditions or in organic solvents. It is well known that
in fruit trees blooming at night such as cherimoya
(Utsunomiya et al., 1992) and durinn (Bala, 1996),
pollen loses its viability under dry conditions. This also
applies to the dragon fruit. Therefore, it is necessary to
prevent pollen from drying during storage and
artificial pollination.
When pollen was stored at -20 •Ž and -30 •Ž for 15
days, pollen germination and tube elongation were
reduced to 7.6 and 4.3% and 255 m and 165 m,
respectively (Table 3). Peach and pear pollen stored
for more than 6 years at -20•Ž was successfully used for
artificial pollination (Akihama et al., 1978), and Mizuno
et al. (2002) also reported the same results at -20 •Ž
storage for peach pollen. In the present study, the
pollen germination percentage after 15 days of storage
was significantly lower at -20•‹and -30 •Ž than at 5 •Ž
(Table 3). Pollen of cherimoya (Yonemoto et al., 1999)
loses its viability under dry conditions, and also cannot
be stored under freezing conditions. However, white
sapote pollen can be stored under dry conditions and
at freezing temperatures (Yonemoto et al., 2000) . Since
the dragon fruit is similar to cherimoya, pollen storage
at freezing temperature should be avoided.
The percentage of sucrose solution affected the
pollen germination and tube elongation in artificial
media (Fig. 2). Pollen germination did not occur within
the sucrose solutions regardless of the concentration
during storage (Data not shown). High values for the
germination percentage and tube elongation which
were observed after pollen storage in 30, 40 and 50%
sucrose solutions from day 1-5, decreased dramatically
thereafter. Germination percentage was markedly
reduced from day 1 in 60% and 20% sucrose solutions,
while germination did not occur when the pollen was
stored in solutions lacking sucrose or containing 5 and
10% sucrose. These results indicate that when the
dragon fruit pollen is too wet, viability is lost. In the
passionfruit, no germination was observed for the
pollen collected from anthers that had been wetted by rain and the fruit set of purple passionfruit decreased
due to the loss of pollen viability (Ishihata, 1991). In
the dragon fruit, heavy dew at night affected the fruit
set in commercial cultivation in Okinawa. Wetting of
pollen by dew may decrease pollen viability, resulting in a low fruit set. Furthermore, rain could decrease the
fruit set completely. Therefore, farmers should
consider protecting the flower from rain by using a
plastic cover during the blooming period. Papaya
(Bala, 1996) and peach (Mizuno et al., 2002) can be
pollinated by aqueous pollen spray. In the present study, dragon fruit pollen stored in 30-50% sucrose
solutions germinated on agar, which indicates that
pollination may be possible by aqueous pollen spray. However, further experiments for improving aqueous
pollen spray should be carried out because this
Table 3 Effect of storage methods on pollen germination percentage and pollen tube elongation
Fresh pollen was collected at 7:00 am on June 26, 2005 from 10 blooming flowers.
0.1g of pollen was dissolved in 5 ml of each organic solvent and stored at 5 •Ž for 20 hrs. Pollen grains
were filtered with a filter paper and air-dried at room temperature for 10 minutes before being plated.
0.1g of pollen was wrapped with a powder paper and sealed in a vial and stored at -20 or -30 •Ž for 15 days
and at 5 •Ž with or without silica gel for 20hrs.
Pollen was plated on 2% (w/v) agar media containing 30% (w/v) sucrose and 500ppm boric acid.
Measurements were performed after 24 hrs. of incubation at 30 •Ž on the media.
Mean separation in columns by Tukey's-test, p<0.01.
n =10 and 20: germination percentage and tube elongation, respectively.
Macha et al.: Dragon fruit pollen germination 55
Fig. 2 Effect of pollen storage in sucrose solution on pollen germination percentage and
pollen tube elongation.
Pollen solution was plated on 2% (w/v) agar media containing 30% sucrose (w/v) and
500ppm boric acid.
Measurements were performed after 20 hrs. of incubation at 30•Ž on the media.
Vertical bars indicate SE (n=10 for germination percentage, n=20 for tube elongation).
method is easier than pollination with a brush.
Fresh pollen of dragon fruit stored in a vial at 5 •Ž
remained viable at a rate of more than 25% until 8 days
and the viability dramatically decreased to 0% at 25
days (Fig. 3). However, the pollen tube length
decreased slowly after 8 days of storage. Pollen stored
in a refrigerator can be used for artificial pollination
until 8 days but further experiments should be carried
out to determine its practical use after 8 days. In
Okinawa, WD cultivars bloom at 9 to 15-day intervals.
It would be preferable for the growers if the pollen
could be stored in a refrigerator for 15 days.
In conclusion, pollen viability of the dragon fruit
can be easily observed on 2% agar media containing
30% sucrose and 500ppm boric acid at 30-40 •Ž. The
pollen loses its viability under too dry or wet
conditions. Fresh pollen can be stored in a vial at 5 •Ž
for 8 days. Storage of pollen in a freezer has not yet
been evaluated.
References
Akihama, T, M. Omura and I. Kozaki 1978. Further investigation
of freeze-drying for deciduous fruit tree pollen. Fruit Tree
Research Station A72: 1-7.
Bala, J. I. 1996. Practical and efficient techniques of pollen
delivery for pollination in selected fruit tree crops.
Proceedings International Conference on Tropical Fruit Vol.
II: 59-64.
Ganeshan, S. and M. P. Alexander 1991. Cryogenic preservation
of lemon (Citrus limon Burm.) pollen. Gartenbauwissenshaft
56: 228-230.
Ishihata, K. 1983. On the pollen germination of purple passion
fruit, Passiflora edulis Sims. Bulletin of the Faculty of Agric.
Kagoshima Univ. 33: 7-11.*
Ishihata, K. 1991. Studies on pollen germination and tube growth
from normal and upright style flowers in purple passion
fruit, Passiflora edulis Sims using various artificial media.
Jpn. J. Trop. Agric. 35: 98-103.
Karp, D. 2003. Enter the Dragon Fruit. Tropical Fruit News
March/April: 3-7.
Ke, N. V. 1997. Dragon Fruit (Pitaya). In: Tropical Fruit in
Vietnam (Akihama, T, Y. Tanaka and T. Tanaka eds.) The
foundation of agricultural development and education.
Fig. 3 Time course changes in pollen germination percentage
and tube elongation of dragon fruit pollen stored at 5•Ž.
Pollen was plated on 2% (w/v) agar media containing 30%
(w/v) sucrose and 500ppm boric acid.
Measurements were performed after 20 hrs. of incubation
at 30•Ž on the media.
Vertical bars indicate SE (n=10 for germination percentage,
n=20 for tube elongation).
56 Jpn. J. Trop. Agr. 50(1) 2006
Agricultural bulletin series 1:13-16.**Loupassaki, M., M. Vasilakakis and I. Androulakis 1997. Effect of
pre-incubation humidity and temperature treatment on the in vitro germination of avocado pollen grains. Euphytica 94:
247-252.Mizrahi, Y., A. Nerd and P. S. Nobel 1997. Cacti as crops. Hort.
Rev. 18: 292-320.Mizuno, S., K. Waki and R. Todo 2002. Studies on the labor-
saving technique for the artificial pollination of peach trees-Pollen storage and pollen spraying methods for the artificial
pollination. Bulletin of the Faculty of Agric. Tamagawa University 42:1-14.*
Morton, J. F. 1987. Strawberry Pear. In: Fruit of Warm Climates. Media Incorporated (North Carolina) 347-348.
Nomura, K., M. Ide and Y. Yonemoto 2005. Changes in sugars and acids in pitaya (Hylocereus undatus) fruit during development. J. Hort. Sci. Biotech. 80: 711-715.
Popenoe, W. 1917. The pollination of mango. U.S. Dept. Agr. Bull. 542:1-20.
Raveh, E., A. Nerd and Y. Mizrahi 1997. Responses of two hemiepiphytic fruit-crop cacti to different degrees of shade. Sci.Hort. 53:115-122.
Utsunomiya, N., H. Higuchi, Y. Yonemoto and S. Yamashita 1992.
Effect of relative humidity on pollen storage and fruit set in cherimoya. J. Japan. Soc. Hort. Sci. 61(Extra issue 1): 172-173.**
Watanabe, K. and B. Takahashi 1989. Factors influencing pollen longevity, germination, and tube growth in vitro of kiwi fruit, Actinidia deliciosa, cv. Matsua. J. Japan. Soc. Hort. Sci. 57: 591-596.*
Yamamoto, S., H. Inoue, Y. Yonemoto, H. Higuchi and E. Nawata 2004. Isozyme analysis of Dragonfruit in Okinawa. Jpn. J. Trop. Agric. 48: 115-119.*
Yonemoto, Y. and C. K. Hennayake 2002. Pollen tube growth in the pistil as affected by temperature and effective pollination
period in white sapote (Casimiroa edulis Llave and Lex.). Jpn. J. Trop. Agric. 46: 77-81.
Yonemoto,Y., H. Higuchi, K. Ishihata and E. Tomita 2000. Effect of artificial medium conditions on in vitro germination and
storage conditions of white sapote (Casimiroa edulis Llave and Lex.) pollen. Jpn. J. Trop. Agric. 44: 171-177.*
Yonemoto, Y., H. Higuchi, T Nakanishi and T Tomita 1999. Conditions of artificial media for pollen germination and tube growth of cherimoya (Annona cherimola Mill.). Jpn. J. Trop. Agric. 43: 260-264.*
(*: In Japanese with English summary, **: in Japanese)
ドラ ゴ ン フル ーツ(Hylocereus undatus Britt & Rose)花 粉 のin vitroで の
花 粉発 芽 に及 ぼ す人 工 培地,気 温 お よび花 粉 貯 蔵 法 の影 響
Mustad Malid MACHA1・Abul Kashem CHOW DHURY2・ 村 田 達 郎3・ 米 本 仁 巳4*
1ソ コイネ農業大学農学部 ,タ ンザニア2パ ツアクハリ科学技術大学植物遺伝 ・育種学部 ,バ ングラデシュ3九州東海大学農学部
4国 際農林水産業研究センター沖縄支所
要 約 白 肉系 ドラゴ ン フル ーツ(ピ タヤ)は 自家結 実性 で あ るが,赤 肉系 は 自家不 和合 性 で,白 肉系 の花 粉 を授 粉 して 結
実 させ る.こ の た め,授 粉 に用 い る白肉 系の 花粉 の最 適発 芽 条件 を,寒 天 培地 に含 まれ る シ ョ糖濃度 お よび発 芽温 度 を変 え
て検 討 した.さ らに,花 粉 の保 存法 を異 な る貯蔵 条 件下 で検討 した.
寒 天培 地 に含 まれ る シ ョ糖濃 度 は30%が 花 粉 発芽 お よび花 粉管 伸長 に最 適 で,20%以 下 と40%以 上 で発 芽率 が低 下 し,0%
と50%で は発 芽 しなか った.花 粉 発芽 に最適 な温 度 は30,35お よび40℃ で,45℃ 以 上 と25℃ 以 下 で低 下 し,50℃ と10℃
で は発芽 しなか った.採 取 直後 の新 鮮花 粉 お よび5℃ で20時 間貯 蔵 した花 粉 の発芽 率 は30%以 上 で あった が,シ リカゲル と
共 に5℃ で20時 間 おい た花粉 は発 芽 しなか った.-20と-30℃ で15日 間貯 蔵 した花 粉 の発芽 率 は低下 した.ア セ トン または
酢酸 エ チル に貯蔵 した花粉 は発 芽 しなか った.20～60%(w/v)の シ ョ糖液 中 に5℃ で貯蔵 す れ ば3日 間 は発芽 率 を維持 した.
しか し,10%以 下 の シ ョ糖 液 に貯蔵 した花粉 は発芽 しなか った.
これ らの こ とか ら,白 肉 系 ドラ ゴ ンフル ー ツの 人工 培 地上 で の花 粉 の発 芽 と花 粉 管 伸長 には シ ョ糖30%で30,35ま たは
40℃ が最 適 で あ る.し か し,花 粉 貯蔵 に は乾燥 あるい は過湿 を避 ける必要 が あ る.
キ ー ワー ド:花 粉 貯蔵,花 粉 発芽率,寒 天 培地,シ ョ糖 濃度,培 養温 度,ピ タヤ
*Corresponding author
〒907-0002沖 縄 県 石 垣 市 真 栄 里