Đề tài: Đặc điểm ra hoa và phát triển trái của cây dừa nước (IMypa fruticans Wurmb) tại 3 vùng nước mặn, lợ và ngọt ở Đồng bằng sông Cửu Long

Mời các bạn cùng tham khảo nội dung đề tài Đặc điểm ra hoa và phát triển trái của cây dừa nước (IMypa fruticans Wurmb) tại 3 vùng nước mặn, lợ và ngọt ở Đồng bằng sông Cửu Long để nắm bắt được đặc điểm ra hoa và phát triển trái của cây dừa nước, các biện pháp để sản xuất nhựa buồng hoa,...

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Nghidn cuu dugc thuc hi£n tr£n cay dua nuoc d ba di£m thupc huy£n Trin D£, Dai Ngai tinh Soc Trtng vi

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bui dira nuoc va 10 tau la moi Su ting trudng cua hoa vi trai dugc tinh toin theo phuong trinh ting truong

dx/dt = kx (a-x) cua Robertson (1908, trich dan bdi Reed, 1920) K£t qui cho thiy d ba vung nude min,

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1 BAT VAN B£

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ngap man nhidt doi (Hutton, 1996) Cay dua nuoc

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cham va c6 nhidu phu sa (Toe et al., 2010) Trong dir

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1.000 m2 Trong khi dd, kich thich cho buong hoa tidt

nhua cd thd dung dd chd bidn th4nh dudng, giam,

rupu, (Samarajeew, 1985) Theo Van Die (1974)

nang suit dudng tir nhua budng hoa cay dua nude cd

thd dat 15-20 tin/ha so vdi c4y mia chi dat 5-15

tin/ha/nam M$c du hiu hdt c4c c4y thudc hQ Cau

Dira ddu cd thd t4c ddng cho nhua budng hoa tidt

nhua (Tuley, 1965), tuy nhidn, mdi logi c4y lgi cd

1 Bp mon Khoa hpc ciy trong • Khoa Ndng nghiep v i Sinh

hpc Ung dyng, Dgi hpc Can Tho

50

phuong ph4p khai th4c kh4c nhau, phu thudc chu ydu v4o dac tinh cua timg c4y Do dd, dd khai th4c dugc nhua buong hoa phuc vu cho nhu ciu san xuit thuc phim thi cin bidt dugc d$c tinh ra hoa phit tridn tr4i cua c4y dira nude 6 Vidt Nam noi chung v4 ddng bang sdng Cuu Long (DBSCL) ndi ridng hiu nhu chua cd cdng trinh nghien cuu nao vd c4y dua nude Do dd, dd tai dugc thuc hidn nham myc tidu x4c djnh d4c didm ra hoa v4 phit tridn tr4i cua ciy dua nude d ba viing nude m4n, nude ngpt v4 nude lgr 14m co sd cho vide nghidn cuu c4c bidn ph4p dd s4n xuit nhua budng hoa

Z PHUONG T fr V A PHUONG PHAP

Thi nghidm dugc thuc hidn trdn c4y dira nude b '

ba didm thupc huydn Trin Dd v4 Dgi Ngai tinh Sdc Trang v4 huydn C4ng Long tinh T ri Vinh tu 11/2010 ddn 2/2012 Vung Trin Dd dac trung cho vung nude mgn, viing C4ng Long d$c trung cho vung nude kr v i vung Dgi Ngai d$c trung cho vung nude ngpt Mdi vung khio sit 40 budng hoa (10 budng hoa theo ddi

sy phit tridn, 30 budng dung dd thu «n&« kh*n s& sv phit tridn budng hoa, trii), 50 budi dua nude (xic dinh mua vy ra hoa) v i 10 tiu l i mdi dupe hinh thinh khoing 30 cm C ic chi tidu theo ddi bao gdm: a) Mua vy ra hoa dugc ghi nhin bing cich ddm tdng

sd budng hoa xuit hidn/tdng sd li cd (30 ngiy/lin ),

sy phit tridn vd chidu cao cua li dugc do tu goc ddn

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dinh tau Id (15 ngay/lan); b) khao sat su phat triln

buong hoa va trai (moi vung Idy ba buong hoa, lay 10

tr4i/buong): kich thuoc cua buong hoa, chieu dai

cudng buong hoa, chu vi cua buong hoa theo chilu

rpng v4 chilu cao (15 ngay/lan) Khoi luong cua

buong hoa, tdng sd trai/buong, ti Id trai chdc (30

ngay/ldn) Do min cua nuoc dugc do vao ngay 14

din 16 hang thang khi nuoc dang ldn, do 6 do sau

c4ch mat nuoc 20 cm Su tang trudng cua budng hoa

dugc tinh toan theo phuong trinh tang trudng dx/dt

= kx (a-x) cua Robertson (1908, trich dan bdi Reed,

1920) Trong dd x la gia tri quan sat (qs), t la thdi

dilm quan sat, a la sd cuoi cung cua gia tri xqs+SE, tj

la thdi gian d gi4 tri x = a/2, k la hang sd

s n £ tqu A v a h U oluan

3.1 Biln ddng vl dd m$n cua nude dr ba dilm

khio s4t

Qua khao sat do m4n cua nuoc d ba diem cd su

kh4c nhau va biln dong qua cac thang (Hinh 1)

Dilm thi nghidm thuoc huydn Tran D l cd do man

cao nhait v4 dp man luon duy tri d muc rat cao vao cac

thing trong nam so vdi hai dilm cdn lai Tai Tran Dd

dd man trong nude vao thang ba 14 cao nhat

(20,82±0,27%o) O dilm thi nghidm thuoc huydn Dai

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gi4 trj dd man rat nho khdng vupt qua 0,l%o qua cac

thing T?ii C4ng Long thi do man trong nude cd su

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nhit l,33±0,08%o Theo to chuc Y te thi gidi (WHO)

dp man cho phep trong nude uong nam d nguong

0,25%o Nhu vay, dua vao do man cd thi phan ra day

14 ba vung nude Tran D l 14 vung nude man, Dai Ngai

14 vung nude ngpt v4 C4ng Long 14 vung nude lo

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Hinh 1: Sy biln ddng dd m$n cua nude dr ba dilm

thi nghi£m huydn Trdn D l v4 huydn D<u Ngai,

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3.2 Mua vu ra hoa Cay dira nude d tat ca cac thang trong nam thi dlu hau het cd su xuat hidn cua phat hoa mdi (Hinh 2) Tuy nhidn, d ba vung thi dua nude ra hoa tap trung trong mua kho tu thang 11 den thang 4 ndm

sau O vung nuoc man thi cay dua nude ra hoa tap

trung vao thang 11 ddn thang 3 ndm sau, trong khi

dd d vung nude ngot thi cay ra hoa tap trung nhidu nhat tu thdng 1 ddn thang 4 6 vung nude lp thi cdy hau nhu ra hoa quanh nam Nhu vay co thi thay rdng, cay dua nude ra hoa tap trung vao cac thdng mua kho vd thdng cuoi mua mua, vao cac thdng mua mua thi cay rat it ra hoa Theo Toe et al (2010) thi cay dua nude phat triln trong bai bdi, noi thuy triiu chay cham, nude song cd nhilu phu sa ndn vao mua kho muc nude khong qua cao Id dilu ki|n thudn lpi

dl c4y ra hoa Tinh trong c4 ndm thi ti Id c4y dua nude ra hoa cao nhat 14 d vung nude man (72%), kd ddn 14 vung nude lp (68%) v4 thap nhat 14 vung nude ngpt (60%) Ti Id ra hoa d ba vung n4y ddu cao hon so vdi cay dua nude d Papua New Guinea 14 49% (Paivoke, 1985) Su chdnh ldch vl ti 1| ra hoa cua ba vung cd thi 14 do su kh4c bidt vl moi trudng sinh

sdng vi theo Joshi et al (2006) thi moi trudng thich

hpp cua dira nude 14 mot ti Id pha lodng cua nude biln bdi ddng nude ngpt ch4y dpc theo hudng biln

□ ViggoDc min ■ Ving <ux ngpt ■ Ving nuoc lp

Ttagrakot

Hinh 2 Mua vy ra hoa cua cdy dira nude

d ba vung nude man, nude ngpt v4 nude lp 3.3 Chilu cao 14

Tai thdi dilm vira t4ch ra khoi 14 m? cho din 8 th4ng sau thi chilu cao 14 giua ba vung cd su kh4c bidt d muc y nghia 5% qua phan tich thong kd (Hinh 3) Chilu cao 14 dira nude d vung nude lp v4 nude ngpt kh4c bi|t khdng y nghia, nhung c4 hai lai kh4c bidt cd y nghia so vdi vung nude man qua t4m th4ng

KHOA HOC CbNG N G H l

khao sat Thuc hi£n vi£c tinh toan theo phuong trinh

tang trudng cua Robertson (1908), chieu cao la dat

toi da la 713,9±75,2 cm (nude man), 841,5±88,1 cm

(nude lg) va 796,&t84,4 cm (nude ngot) Chi£u cao la

dat toe do tang trudng cue dai tai thdi diem 3,76

thang (nude man), 3,73 thang (nude lo) va 3,66 thang

(nude ngot) Tir thdi di<?m nay trd di thi toe do gia

tang v£ chieu cao cua la cham lai cho den khi 14 dat

chi£u cao tdi da Thdi gian la tang trudng dat toe do

toi da d ca ba vung nam trong khoang 3,54 thang

sau khi tach ra khoi 14 me L4 dira nude can thdi gian

khoang s4u th4ng d<? co th£ dat chi^u cao toi da La

dira nude khi dat chi£u cao tdi da d ba viing nude n4y

gan bang vdi la d Singapore 14 9 m (Toe et al., 2010),

nhung thap hon rat nhi£u so vdi d Papua New

Guinea 14 11,7-14,2 m (Paivoke, 1985)

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(b) Hinh 4 Sy ph4t tri£n (a) v4 tde dd ting trudng (b) cua khdi lugng budng hoa dira nude d ba vung nude

m$n, nude lgr v4 nude ngpt

x tinh toan theo phucmg trinh tin g trudng cua Robertson (1908, trich dan bdi Reed, 1920) vdi

lp), Y=0,29xfI00&x) (nuoc ngpt)

Hinh 3 Sy ph4t tri&i (a) v4 tde dd ting trudng (b)

cua chi£u cao 14 dira nude d ba vung nude m$n, nude

lgr v4 nude ngpt

x tinh toan theo phuong trinh tdng trudng cua

Robertson (1908, trich ddn bdi Reed, 1920) vdi

Y=0,27xT13-92x) (nuoc man), Y=0,27x(84l51'x } (nudc

3.4 D$c tinh budng hoa

3.4.1 Khdi lupng budng hoa

Budng hoa dira nude dat khdi lugng tdi da d

th4ng thu s4u, sau dd dn djnh ddn th4ng thu mudi

(Hinh 4, 5) Dua v4o phuong trinh tang trudng cua

Robertson (1908) cho thay khdi lugng budng hoa

tang trudng cue dai d thdi di<?m 4,39 th4ng d viing

nude man, 4,08 d viing nude lgr v4 4,15 th4ng d vung

nude ngot Khdi lugng budng hoa d viing nude lgr v4

nude ngot cao hon so vdi viing nude man O Papua

New Guinea, Paivoke (1985) nh4n thay khdi lugng

budng dira nude bi£n dong tir 6,1 d&i 30 kg/buong

Nhu v4y, d viing nude man khdi lugng budng dira

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Hinh 5 Sy ph4t tri£n cua budng hoa dira nude d

vung nude ngpt

3.4.2 Kich thudc buong hoa

Chu vi budng hoa theo chi£u cao v4 chi£u rdng tir khi budng hoa mdi no cho d£n giai doan b4y th4ng sau khi hoa no d ba vung d£u cd su kh4c bi£t thdng k£ d muc y nghia 5% d timg thdi di&n quan sat (Hinh

bi£t khdng y nghia v4 c4 hai cung khac bi£t cd y nghia vdi budng hoa viing nude m^n Dya vao phuong trinh ting trudng cua Robertson (1908) thi chu vi budng hoa theo chi£u cao v4 chi^u rdng d^t tdi da 14 89,9*8,2 cm v4 90,1±11,3 cm (nude m$n), 102,1± 10,6 cm v4 101,9tl3,3 cm (nude lg), 102,4±9,3

cm v4 101,8±12,8 cm (nude nggt) Chu vi budng hoa theo chi£u cao va chi£u rdng gia tang tir khi hoa nd v4 dat tde dd tang trudng eye tai tai thdi diem 3,1 th4ng v4 3,07 thing (nude min), 3,06 thing vi 3,03

KHOA HOC C6NG NGHt

thang (nude lgr), 3,06 thing vi 3,05 thang (nuoc

ngpt) Nhu viy, chu vi buong hoa theo chilu cao va

chilu rpng a ba vixng la khic nhau Ion nhat la or vung

nuoc lp va thip nhit li vung nuoc min Thoi gian can

thilt dl chu vi buong hoa theo chilu cao vi chilu

rong dat kich toi da li siu thing sau khi hoa ncr Toe

dO ting truong cuc dai cua chu vi buong hoa theo

chilu cao vi chilu rpng nim trong khoang tir thing

thu ba din thing thu tu sau khi hoa no

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Hinh 6 Sy phit triln (a) v i tdc d0 ting tru6ng (b)

cua chu vi budng hoa theo chilu cao b ba vung nude

min, nu6c lp v i nude ngpt

x tinh toin theo phuong trinh ting trudng cua

Robertson (1908, trich dan bdi Reed, 1920) vdi

Y~0,34xf892**) (nude m$n), Y=0,33x<1020*x >(nudc

lgr), Y*0,32x°02-3*X) (nude ngQt)

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ngpt 79,1-89,3 trai/buong Giua ba vung tr£n khong

co su khic bi£t vl tong so trai/buong co thi dugc giai thich la do tong so trai/buong hoa dua nude hau nhu da dupe quylt dinh ngay trong giai doan buong hoa dupe hinh thinh, do do hau nhu tdng so trii/buong khong co su thay doi trong suot giai doan buong hoa phat triln Tuy nhi£n, tong so trii/buong hoa cua ba vung nuoc nay cung nho hon so voi tong

sd trii/buong hoa d Papua New Guinea li 111 trii/buong (Paivoke, 1985)

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Hinh 7 Sy phit triln (a) vitd c do ting trudng (b)

cua chu vi bu6ng hoa theo chilu r0ng b ba vung

nude min, nude lp v i nude ngpt

x tinh toin theo phuong trinh ting trudng cua

Robertson (1908, trich din bdi Reed, 1920) vdi

Y-0,32xmi**) (nude m$n), Y-QJlxf™** }(nudc

lp), Y-0,31x°0lsr*} (nude ngpt)

3.4.3 Tdng sdtrii/budnghoa

Tdng sd trii/budng hoa b ba vung khdng cd sy

khic bi$t b muc i nghia 5% qua phin tich thong k l b

timg thing khio sit (Hinh 8) Tdng sd trii/budng

hoa cua viing nude mgn trung binh vio khoing 77,3-

86,3 trii/budng, nu6c 77,3-94,7 trii/budng v i nude

Hinh 8: Tdng sd trii/budng hoa dua nude b ba viing

nude m$n, nude ngpt v i nude lp

3.4.4 Ti 16 trii chic/budng hoa

Ti 10 trii chic/buong hoa khdng cd su khic bi|t

or muc y nghia 5% qua phin tich thdng k£ giua ba viing qua timg thing khio sit (Hinh 9 ) Khi budng hoa dira mdi nor, chua x ic djnh dugc trii chic vi trii lep do luc niy buong hoa mdi buoc vio giai doan thu phan v i cd thi thay ring tat ca cic trii dlu cd thi tro thinh trii chic 6 giai doan mdt thing sau khi hoa

no thi sd trii chic/buong cua budng hoa dira nude tai ba vung dlu cao hon so vdi cic thing cdn lgi Dilu niy li do b giai do?n mpt thing sau khi hoa no thi budng hoa luc niy cung chua cd sy thay ddi ldn

v l kich thudc trii do dd lupng trii duge xic dyih li trii chic tuong ddi cao Tuy nhi£n, din thing thu hai thi luc niy trii d i bit dau phit triln v l kich thudc v i hiu nhu nhung trii dira nude tr£n cung mdt budng

se phit triln hinh dang dua hoin toin vio khdng gian m i chung cd dupe, b giai do^n niy cd sy c?nh tranh v l khdng gian d l t?o thinh hinh dang cua moi trii Do dd, b thing thu hai thi d i cd sy phin bi|t rO rang giua trai chic v i trii lep, ddng thdi hinh d?ng cua moi trii cung d i duge quylt djnh Ti 1| trii chic/buong tinh tir thing thu hai din thing thu 10 cua viing nude min trung binh vio khoing 47,8- 60,93%, nude ngpt 50,1-60,2% v i nude lp 48,963,4%

KHOA HPC CONG N GH l

Thang u u khi hoa nd

Hinh 9 Ti l£ trii ehac/budng hoa dira nude d ba

vung nu6c m$n, nude ngpt vi nude lgr

3.5 Khdi luong trii chic

Trai chic dat khoi lugng toi da d thang thu sau,

sau do on dinh toi thing thu muoi (Hinh 10) Phuong

trinh ting truong cua Robertson (1908) cho thay

khoi luong trai chic tang trudng cuc dai d thdi di£m

4,78 thang d vung nuoc man, 4,52 d vung nude lgr va

4,55 thang d vung nude ngot Trong do, khoi lugng

trai chic d vung nuoc man khac biet cd y nghia so

vdi khoi lugng trai chac d hai vung nude ngot va lgr

Nhu vay, khoi lugng trai chac cao nhat la d vung

nude lgr va thap nhat 14 d vung nude man

d£u co su khic bi£t thong k£ d muc y n gh ia 5% d timg thdi di£m quan sat Dua vao phuong trinh tang trudng cua Robertson (1908) thi chi£u dai trai gia tang tir khi hoa no va dat toe do tang trudng cue t^i tai thdi diem 3,14 thang (nude man), 3,0 thang (nude lo), 3,06 thang (nude ngot) Tuong tu nhu khao sit d Papua New Guinea, chi£u dai trai bi£n dong 12,4- 14,7 cm va chi£u rong trai 6,2-7,6 cm (Paivoke, 1985) Nhu vay, chieu dai trai ldn nhat la d vung nude lo, thap nhat la viing nude man Thdi gian can thi£t d<? trai dat kich toi da la sau thang sau khi hoa no Toe

do tang trudng cuc dai v£ chi<ki dai cua trai nam trong khoang tir thang thu 2 ddn thang thu tu sau khi hoa nd

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Hinh 10 Su phit tri£n (a) v i tdc dd tang truong (b)

cua khdi lugng trii chic cua trii dira nude dba viing

nude m$n, nude lgr v i nude nggt

x tinh toin theo phuong trinh tin g truong cua

Robertson (1908, trich din bdi Reed, 1920) vdi

lo), Y=0,35x(,9IO'x) (nude ngQt)

3.6 Kich thudc trii ch£c

Chi£u dai (Hinh 11) cua trii chic tir giai doan

mdt thing ddn 10 thing sau khi hoa nd d ba vung

Hinh 11 Su phit tri£n (a) vi tdc do ting trudng (b) cua trii chic theo chi£u cao d ba viing nude min,

nude lgr v i nude nggt

x tinh toan theo phuong trinh tin g trudng cua Robertson (1908, trich dan bdi Reed, 1920) vdi

3.6 Chi£u dii cudng budng hoa Chidu dai cudng budng hoa dira nude d ba viing

cd su khic bi£t d muc y nghia 5% qua phan tich thong k6 d timg thdi didm khao sit (Hinh 12) Cuong buong hoa dira nude dai nhat li d viing nude lg va thap nhat la d viing nude min Chi£u dai cudng buong hoa dira nuoc gia ting tir khi buong hoa mdi

nd cho ddn giai doan hai thing sau khi hoa nd, sau giai doan niy chidu dai cudng buong hoa dira nude gan nhu khdng cdn ting trudng nua va dat chidu dii tdi da Chidu dai cudng buong hoa dira nude khi d?t kich thudc tdi da d viing nude min la 85,1 cm, nude ngot 101,8 cm vi nude lgr 103,7 cm Nhu vay, cd thd thay chidu dai cuong budng hoa dira nude thay ddi theo timg viing v i didu niy cung d i dugc tim thiy bdi Hamilton and Murphy (1988) dd la chidu dai cua

buong hoa thay ddi theo timg noi b Philippu buong

hoa dii 0,6-1 m, d Sumatra dii 1,4 m

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Hinh 12: Chilu dii cu6ng buong hoa dua 6 ba viing

nu6c m$n, nu6c lgr vi nu6c ngpt

4 NET LUAN VA BE NGHI

4.1 Kltlu$n

- 6 ba viing nuoc man, nuoc lg va nuoc ngpt

cay dira nuoc ra hoa tap trung trong mua kho tir

thing 11 din thang 4 nam sau Ti 16 cay dira nuoc ra

buong hoa a viing nuoc man la cao nhat (72%), thap

nhat la viing nuoc ngpt (60%) Thoi gian can thiet de

buong hoa o ca ba viing phat trien dat kich thuoc toi

da la 6 thing tir khi hoa no

- Viing nuoc man co khoi luong buong hoa,

chu vi buong hoa theo chieu cao, chilu rong, kich

thuoc trai chac, chieu dai cuong buong hoa va chieu

cao cua 14 luon nho hon so viing nuoc lp va nuoc

ngpt Tong so trai/buong va ti le trai chac khong co

su khic bi$t a ba viing.

4.2 Dd nghi

Su ra hoa va phat triln trai cua cay dira nuoc

khic nhau a ba viing nuoc man, lp va ngpt Do do,

cin nghidn cuu bi|n phap tac dong cho buong

hoa tilt nhua thich hop a timg viing d l co thi dat

dupe nang suat va chat lupng nhua buong hoa cao

nhit

TAI LfU THAM KHAO

1 Hamilton, L S and D H Murphy, 1988 Use

and Management of Nipa Palm (Nypa fruticans,

Arecaceae): A Review, Economic Botany 42(2), pp

206-213

2 Hutton, W., 19% Tropical Fruits o f Malaysia

and Singapore, Periplus Edition (UK) Ltd., pp: 18-

25

3 Joshi, L, U Kanagaratnam and D Adhuri,

2006 Nypa fruticans - useful but forgotten in

mangrove reforestation programs? Livelihood and

human welfare World Agroforestry Center, http://

www worldagroforestrycentre org/ Sea/ WNew/ datas Aceh30Nov06/ 7.%20Nypa% 20fruticansuseful%

20but%20forgotten%20in%20mangrove.pdf.

4 Latiff, A., 2008 Malaysian nipah: An appraisal of its scientific, economic potential and

future In Prosiding Seminar Pengurusan dan

Pemuliharaan Nipah 2008 Hotel Vistana, Pulau

Pinang, pp 49-58

5 Nguyln Ngoc Binh, 2004 Cam nang nganh

lam nghiep: Chqn loai cay uu ben cho cac chuong trinh trong rung tai Viet Nam Nxb Giao thong Van

tai, Hi Noi 99 tr

6 Paivoke, A E A., 1985 Tapping practices and

sap yields of the nipa palm (Nypa fruticans) in Papua

New Guinea Agriculture, Ecosystem s and Environment 13, pp 59-72.

7 Phan Van Den, 2012 Dieu tra hiin trang canh

tac va hieu qua kinh ti' cua c iy dira nude (Nypa fruticans) tai huyen Long M y tinh H$u Giang LVTN

dai hoc nginli trong trpt, truong Dai hpc Can Tha, 79 trang

8 Toe, S., W F Ang, A F S L Lok, B R Kurukulasuriya and H T W Tan, 2010 The status and distribution of the nipah palm, Nypa

fruticansWurmb (Arecaceae), in Singapore Nature

in Singapore, 3, pp.45-52.

9 Tuley, P., 1965 Studies on the production of

wine from the oil palm J Nigerian Inst Oil Palm

Res 4, pp 284-289.

10 Van Die, J., 1974 The developing fruits

of Cocos nuciferaand Phoenix dactylifera as

physiological sinks importing and assimilating the

mobile aqueous phase of the sieve tube system Acta

B ot Neerl 23(4), pp 521-540.

KHOA HQC C6WO NGHft

BLOSSOMING AND NUT DEVELOPMENT CHARACTERISTCS OF NYPA PALM GROWN

AT THREE ECOLOGICAL AREAS, SALT AFFECTED, BRACKISH AND FRESHWATER AREA

IN THE MEKONG DELTA

Le Thi Thanh Thuy, Tran Van Hau Summary

This study, conducted on Nypa palm grown at three locations, i.e Tran De and Dai Ngai district, Soc Trang province, and Cang Long district, Tra Vinh province from November 2010 to February 2012, was aimed to investigate blossoming and nut growth characteristics of Nypa palm located at three ecological areas, viz salt affected, brackish, and freshwater area At each location, 40 infructescences, 50 brushwoods, 10 fronds were investigated The growth of infructescence and nut was calculated by Robertson growth equation (1908, cited by Reed, 1920) described as dx/dt = kx (a-x) Results showed that blossoming of Nypa palm occurred during the dry season, from November to April next year The highest blossoming ratio of Nypa palm was observed at salt affected area (72%), while the lowest one was observed at freshwater area (60%) The necessary period for infructescence at the three locaitons to reach maximum size was 6 months, from blossoming At salt affected area, Nypa palm had smaller values of weigh and circumference of infructescence, filled nut size, peduncle length, and leaf height in comparison to that of the palm grown in brackish and freshwater area Among the three areas, there was no significant difference in total number of nut per bunch, and filled nut ratio.

Keywords: Nypa fruticans Wurmb, infructescence, seawater, brackish water, freshwater.

Ngudi pan bi£n: GS.TSKH Trin Th£ Tuc

Ngiy nh£n bii: 29/11/2013

Ngiy thdng qua phin bi£n: 30/12/2013

Ngiy duy£t ding: 6/01/2014