Synchronous Senescence in Neem Trees in Bijnor and Jyotiba Phule Nagar Districts of Western Uttar Pradesh

2007·1.7 MB·

by  Sanjay Kumar

MISCELLANEOUS NOTES
andlateeveninghours.Whiledrinkingnectar,thepasserines, Theleaflessstateoftreesduringflowering,makestheflowers
and Merops orientalis contacted the stamens and stigma, more visible, and may help attract bird visitors, even from a
effecting pollination. The other non-passerines caused long distance.
damage to sex organs while probing the flowers for nectar. These bird-flowers attract both passerine and
Further, they made punctures or holes at the flower base to non-passerine birds. The passerine birds and the
drinknectarandalsoremovedflowerstolookformorenectar. non-passerineM. orientaliseffectpollinationwhileprobing
Both categories ofbirds were regular visitors to B. superba the flowers for nectar. During probing, the birds cause the
until the flowers were exhausted. They made frequent visits release of stamens and stigma from the beak-shaped keel
to other trees ofthe same species in search of more nectar. petal and contact them on their beak and forehead. As the
The Indian Giant Squirrel (Ratufa indica), Bonnet Macaque birdsarefar-flyingandfrequentlymovebetweentreesofthe
(Macaca radiata) and Common Langur(Presbytis entellus) same species in quest of nectar, they effect both self- and
were also found to be regular visitors to the flowers of cross-pollination. The other non-passerines are not
B. superba. The squirrel removed the basal part ofthe keel specialized flower-birds, but use B. superba flowers as a
petals to access the nectar, thereby destroying the flowers. liquidsourceduringthedryperiod,butintheprocessdamage
The monkeys plucked the flowers to eat the nectar-bearing sexorgansandalsoremove alarge numberofflowersdaily,
part of the corolla. The flower-eating activity of all affecting reproductive success. Squirrels and monkeys use
non-passerine birds, except M. orientalis, squirrels and the flowers and contribute to a reduced fruit set rate. The
monkeys were found to be detrimental to the reproductive hectic flower-feeding activity of non-pollinators on
success ofB. superba. B. superba seen in our study appears to be a consequence
B. superba flowers show ornithophilous floral ofreduced or non-availability oftheir natural food sources
—
characteristics(FaegriandvanderFiji 1979) anthesisduring due to degraded forest habitats with reduced biodiversity.
theday,large,odourlessrobustflowers,brightorange-scarlet Nevertheless, B. superba flowers serve as potential feeding
corolla, deep-seated, well-protected nectar and ovary, stationsforvisitingbirds, squirrelsand monkeys during the
production ofcopious amount of nectar and the position of dry season in the Eastern Ghats.
stamens and stigma away from the nectar location. The
ACKNOWLEDGEMENT
standard petal curves downwards, facilitating easy probing
by birds. The keelpetal isbeak-shaped, holding the stamens
andstigmainside,andovertopstheotherthreepetals.Further, The financial support received from the Ministry of
the orientation and the arrangement of the flowers on the Environment and Forests, GovernmentofIndiaisgratefully
inflorescence help birds to probe them in quick succession. acknowledged.
REFERENCES
Ali, S. (1932): Flower-birds andbird-flowers in India.J. BombayNat. Hist. Soc. 35: 573-605.
Dafni, A. (1992): Pollination Ecology: A Practical Approach. Oxford University Press, New York. Pp. 247.
Faegri, K. & L. van der Pijl (1979): Principles ofPollination Ecology. Pergamon Press, Oxford. Pp. 244.
Solomon Raju, A.J. & C. Subba Reddi (1994): Pollination ecology and mating system ofthe weedy mint, Leonotis nepetaefolia R.Br. in India.
Proc. Indian Nat Sci. Acad. B60: 255-268.
27. SYNCHRONOUS SENESCENCE IN NEEM TREES IN BIJNOR AND JYOTIBA PHULE NAGAR
DISTRICTS OF WESTERN UTTAR PRADESH
1
SanjayKumar2
'Accepted July 12, 2003
directorate of Plant Protection, Quarantine and Storage, NH-IV, Faridabad 121001, Haryana, India.
Email:[email protected]
Neem (Azadirachta indica A. Juss.) is a polycarpic where maximum temperatures get as high as 49° C (Anon.
perennial,mediumsized,deciduoustreehavingmedicinalas 1948).The optimum temperature forits growth, however, is
well as insecticidal properties. It is cultivated all overIndia 20-30° C. The Neem tree is described as evergreen because
butthrivesbestinthedrierclimateofthenorth-westernparts. newleavesappearatthetipsofbranchesimmediatelybefore
J. Bombay Nat. Hist. Soc., 104 (1), Jan-Apr 2007 121
MISCELLANEOUS NOTES
orafterabscissionofoldleaves(MohanRamandNair 1996). Table1: SynchronoussenescenceinNeemtreesin
Thus, the tree shows sequential senescence controlled by westernUttarPradesh
internal factors, and the process becomes more prominent Numberoftrees
during the months of February and March, just before the
Location Observed Synchronously Dead
initiationofthereproductivephase,everyyear.Theabscission senesced
ofolder leaves helps the tree to conserve nutrients that are
DistrictBijnor
needed in large quantities during the reproductive phase.
Neem trees cannot withstand waterlogged soils, frost and Chandpur 28 24 1
Goyali 17 17 0
freezing or extended cold conditions (National Research Pheena 31 24 3
Council 1992); however, they have occasionally withstood Ratangarh 10 8 0
temperaturesbelow0°CinDadeCounty,Florida(Anon. 1980). DistrictJyotiba PhuleNagar
Dogra and Thapliyal (1996) have reported that in the dry
localitiesofIndia,Neemtreesmayshedallleavesforabrief ADhmarnoahuara 2272 2169 01
period and, therefore, appear to be deciduous. The Gajraula 24 21 2
developmental processes, in general, are controlled by a Naugaon 21 20 1
number of phytohormones. Amongst them, auxins, Shivala 18 14 0
gibberellinsandcytokininspreventabscission,whileabscisic Total 198 173 8
acid and ethylene promote abscission ofleaves by forming Mean 22.00 19.22 0.89
anabscission layer(DharniandSrivastava2004). S.E.± 2.15 1.88 0.35
Synchronoussenescence(completeleaffall), which is
a common phenomenon in plants like Grapevines (Vitis western Uttar Pradesh. Consequently, severe cold wave
vinifera). Peach (Prunus persica), Poplar (Platanus conditionsi.e. meanmaximumtemperature 15°C(7°Cbelow
orientalis) and Pipal (Ficus religiosa), was also noticed in normal), and mean minimum temperature 4° C (4° C below
Neemtrees(youngeronesandeventhosemorethan50years normal)prevailedinthewesternUttarPradeshuptothethird
old) in Bijnor and Jyotiba Phule Nagar districts of western weekofJanuary 2003. Thetotalrainfallduringthe monthof
Uttar Pradesh during the winter of 2003. To observe the January2003was22mm-4mmabovenormal(Anon.2003).
phenomenon critically, Neem trees in residential areas, Since synchronous senescence is governed by
agricultural fields and along roadsides were marked, at four environmentalfactorsratherthaninternalfactors(Dhamiand
locations in Bijnor district and at five locations in Jyotiba Srivastava2004), duringJanuary 2003, the severecold spell
PhuleNagardistrict. Theobservations were madeatweekly coupled with frosty conditions throughout the month may
intervals starting from the second week ofJanuary 2003 to be regarded as the stress factors, and the commencementof
the fourth week of April 2003. The trees denuded almost synchronous senescence in Neemtrees as strain. In general,
completely were considered synchronously senesced, and the low temperature range results in dehydration and frost
ofthemthosethatfailedtobearnewfoliagewereconsidered injury to the protoplasm; also, the roots of temperate
dead.Thedetailsoftreesobservedatdifferentlocationshave deciduous trees do not absorb sufficient water from soil.As
beenpresented inTable 1.Theresultsrevealedthat 173 trees aresult ittendstoreducetherateoftranspirationlossthrough
out of 198 observed (87.37%) exhibited synchronous abscission of leaves. Thus, at low temperatures, the
senescence. Laterwiththe rise in temperature, by thefourth production of phytohormones in Neem trees alters to save
weekofMarch2003,sproutingofapical,auxiliaryandfloral the plant from the adverse environmental conditions, and
budswasobservedalloverthegrowingpartsofthesedenuded subsequently Neem trees exhibit synchronous senescence-
trees, and thereafterthese trees had the green foliage crown a tolerance type ofstress resistance.
asbefore(Photographicevidenceprovided-Eds.).However, The Neem trees survived severe cold and frosty
8denudedtrees(4.62%)failedtosurvive. conditions through alteration in the normal physiology by
It has been reported that there were repeated western showingsynchronoussenescence,wherefunctionalcapacity
disturbances as an upperairsystem, extending upto 4.5 km decreasesandcellularbreakdownincreasestemporarily.The
abovemsl,overnorth-eastRajasthanandHaryana, andover observations made during subsequent years revealed that
north Pakistan and Jammu & Kashmir and Punjab regions Neem trees showed usual sequential senescence and not the
during the last week of December 2002 and throughout the synchronous senescence. The reason may be that the cold
month ofJanuary 2003. There was alsoaninducedcyclonic waves did not prolong beyond a week, which were well
circulationoverthenorthernpartsofRajasthan,Haryanaand tolerated by the Neem trees.
122 J. Bombay Nat. Hist. Soc., 104 (1), Jan-Apr 2007
MISCELLANEOUS NOTES
REFERENCES
Anon. (1948): Azadirachta A. Juss. Pp. 140-142. In: The Wealth of Dogra, P.D. & R.C. Thapuyal (1996): Gene resources and breeding
India. Volume 1, A-B (Eds: Manjunath, B.L.). Publication and potential. Pp. 27-32. In: Neem (Eds: Randhawa, N.S. &
Information Directorate, CSIR, New Delhi. B.S. Parmar). Society of Pesticide Science, India. New Age
Anon. (1980): Firewood Crops - Shrub and Tree Species for Energy International (P) Ltd., Publishers, New Delhi.
Production. Vol. I. National Academy Press, Washington, D.C. MohanRam. H.Y. & M.N.B. Nair(1996): Botany. Pp. 6-26. In: Neem
237 pp. (Eds:Randhawa,N.S.&B.S.Parmar).SocietyofPesticideScience,
Anon. (2003): Weekly Weather Report (weeks ending 01.01.2003 to India. NewAge International (P) Ltd., Publishers,New Delhi.
29.01.2003). Indian Meteorological Department, Pune. National Research Council (1992): Neem: A Tree For Solving
Dhami,PS.&H.N.Srivastava(2004):ATextBookofBiology.Pradeep Global Problems. National Academy Press, Washington, D.C.
Publications, Jalandhar, India. Pp. III/73. Pp. 23-30.
28. OCCURRENCE OF A BI-CHAMBERED FRUIT
OF THE RED SILK-COTTON BOMBAX CEIBA
'
VlBHAKAR K. PARALKAR2
'Accepted September 16, 2004
2B 001, Gimar View Apartment, Gokul Angan, Krishna Township, OffAmbadi Road, Vasai (West) 401 202,
Thane district. Maharashtra, India.
During an outing at Sanjay Gandhi National Park,
Borivli, I observed manyfallen fruitsofthe Red Silk-cotton
Bombax ceiba under a tree. While examining the fruits my
attention was drawn to an abnormal bi-chambered fruit; the
laterally formed fruitlet was approximately one third ofthe
originalfruitborneintheoppositedirection; seedswith silk-
cotton were present in both lobes. Fig. 1:Thebi-chamberedfruitoftheRedSilk-cotton Bombaxceiba
Printed by Bro. Leo at St. Francis Industrial Training Institute, Borivli, Mumbai 400 103 and publishedon December 13, 2007
byJ.C. DanielforBombayNatural HistorySociety,Hombill House, Dr. SalimAliChowk.
ShaheedBhagatSingh Road, Mumbai400001. Maharashtra, India.