Institute of Genetics and Developmental Biology

ABSTRACT
One hundred and five mature pods from a solitary tree of Acacia coriacea subsp. pendens Gowen and Muskin growing
in Botanical Garden of University of Karachi, Pakistan, were collected in the month of March 2012 and studied for
various size parameters after air-drying for around two months. The pod weight averaged to 2.23 ± 0.073g (ranging
from 0.9965 to 4.8622g) and tended to distribute normally. The number of mericarps per pod varied by 26.99% and
averaged to 7.24 ± 0.19. The brood size averaged to 4.37 ± 0.19 seeds and tended to be positively skewed. The
frequency of pods containing seed in each mericarp was low (10%). Ninety per cent of the pods had one or more empty
seed chambers. The seed mass per pod varied by a quantum of 44.35% and averaged to 0.5834 ± 0.2892 g and
maximally 1.2572g in one pod. The pericarp mass of pods varied from 0.4934 to 3.5002g per pod (CV: 31.6%). The
weight of single seed for a sample of 399 normal seeds collected from 105 pods was less variable (15.58%) as
compared to the brood size (CV: 44.35%). The weight of individual seed averaged to 139.70 ± 1.0827 mg varying
from 58.4 to 243.7 mg (4.17 -fold variation). The distribution of seed weight of normal seeds was asymmetrical
(negatively skewed). The proportion of pericarp to fruit (PFR) was 73.26 ± 0.899% and proportion of seeds to fruit
(SFR) was 24.45± 0.816%. There was a positive linear relationship between logarithms of seed yield per pod and mass
of the pod (r = 0.7878). The slope of the line (b) was 1.3766, not significantly different from 1 (t = 0.266, NS). Also,
there was significant positive linear relationship between log (number of seeds per pod) and log (pod mass). The slope
(b = 1.0594) of the regression was not significantly different from 1 (t = 0.495, NS). The investment in pericarp
declined with increase of brood size significantly. The increase in brood size in a pod associated positively with seed
mass proportion to pod mass but negatively with pericarp proportion to pod mass. The seed packaging costs for 105
pods was expressed on the basis of pericarp [g.g-1 seeds (SPC1)] and pericarp [g per seed (SPC2)]. The SPC1 averaged
to 3.6399 ± 0.2197 g.g-1 seeds and SPC2 averaged to 0.4277 ± 0.0231 g per seed varying by 69.03 and 55.8%,
respectively. On individual seed basis, seed packaging cost was 3.06 times of the average seed weight. SPC1 and SPC2
both distributed asymmetrically (positively skewed) i.e. the magnitude of the SPC was quite high in few pods -
generally those yielding single seed. On an average 72.35% of the pod mass was allocated to protection and nutrition of
seeds, 25.3% to seed production and 2.39% to the aril (elaiosome) for dispersal due to birds or ants.

Abstract:
The experiment was conducted to observe the influence of Sea salt salinity (0, 0.15, 0.3, 0.6, 0.9 and 1.2% corresponding to ECiw of 0.6, 3.51, 5.24, 9.23, 12.81 and 16.67 dS.m-1, respectively) on seedling growth and the physiological, biochemical and mineral parameters of growth in Acacia coriacea subsp. pendens. On average basis, 50% reduction in seedling growth performance in coastal sandy soil corresponded to ECiw: 14.94 ± 2.18 dS.m-1. Phyllode concentrations of protein, total soluble sugars, proline and phenols increased significantly with the salt stress and the pigments (chlorophylls and carotenoids) concentrations posed a fluctuating behaviour. There was substantial increase in Na and Cl contents of phyllode (306.59 and 213.67 % over control, respectively) in extreme salinity of ECiw: 16.67 dS.m-1. K contents declined under saline environment. K/Na ratio although declined in salinity treatments as compared to the control, it didn’t vary practically amongst the salinity treatments of ECiw: 3.51 to 16.67 dS.m-1. The results are discussed in physiological context.

ABSTRACT

Ten white grub larvae (third instar) were found in the sandy rhizospheres of Acacia nilotica ssp. nilotica seedlings irrigated with saline water of EC: 9.23 and 12.81dS.m-1 for more than two months in Biosalinity Experimental Field, department of Botany, University of Karachi.These larvae were incubated in laboratory. The soil was once sprinkled with tap water to maintain moisture level. After eight days the eight of the larvae died but two turned up into pupa which after around six to eight days gave rise to adult leaf chafer beetle. This organism on the basis of external morphology and genitalia was identified as Adoretus versutus Harold, 1869) - a serious pest on rose and several other plants.  The grubs appeared to be tolerant to moderate level of salinity

ABSTRACT

The pest relationship of Common grass yellow [Eurema hecabe (Linnaeus, 1758)] with Acacia stenophylla A. Cunn. Ex. Benth., an Australian plant grown in the department of Botany, University of Karachi, Pakistan is described. The larva of this beautiful moth is a serious pest of seedlings of A. stenophylla and rapidly devours their young leaves but not the phyllodes.

ABSTRACT
Biomass investment in pods, seeds and seed packaging has been studied in a tree of Delonix regia (Bojer) Rafin from the campus
of the University of Karachi, Pakistan. The pods are woody and tardily dehiscent or indehiscent for long period of time and seeds are mottled and transversely placed in the pod. The weight of air-dried pods (PW) varied from 19.40 to 98.36 g (CV = 34.23%) and
averaged to 61.6797 ± 2.5238g. The pod weight distributed normally [Kolmogorov-Smirnov z (KS-z) = 0.792; p<0.557]. The brood size (TNS, number of normal seeds per pod (sensu Uma Shaanker et al., 1998) averaged to 13.43 ± 0.668 (CV: 41.63%). As the value of KS-z, 0.764, was insignificant (p<0.603) the brood size tended to be normally distributed. The seed mass per pod (SWPP) averaged to 5.3435 ± 0. 2995 g per pod and varied by a quantum of 48.64%. The distribution of mean single seed weight for a pod (MSSW) was symmetrical among the pods. It averaged to 0.3951 ± 0.0117g and varied from 0.1414 to 0.5573g. The pericarp mass per pod varied from 18.15 to 89.31g (CV: 33.79%) and averaged to 56.291 ± 2.271g. The pericarp mass tended to be normally distributed. Some 91.45 ± 0.302 % of the pod biomass was allocated to pericarp (seed protection) and 8.52 ± 0.302 % to the seeds (reproductive function). The three parameters of pod (PW, SWPP and TNS) collectively interacted in a model to significantly influence the MSSW (R2 = 0.899). In split sub models, PW coupled with TNS and SWPP coupled with TNS as independent variables influenced MSSW significantly (p<0.0001) and in both cases TNS (brood size) associated with MSSW negatively. The weight of individual seed for a sample of 946 seeds averaged to 397.40 ± 3.936mg varying from 55.81 to 638.10 mg (11.52-fold variation). Seed packaging cost (SPC) in D. regia was 11.912 ± 0.5272 g.g-1.seeds and 4.5493 ± 0.1882 g.seed-1 - quite higher than several pod-dehiscent-legumes. The seed packaging cost (SPC2 = g.g-1.seeds) related with brood size in accordance with a negative power model (exp. = -0.54841) i.e. the
investment of biomass in pericarp had a negative trade-off with brood size.

ABSTRACT
Seedling characteristics of Erythrina suberosa Roxb. are described. Its seeds were collected from a tree growing in
the Campus of University of Karachi and germinated without any dormancy breaking treatment in pots filled with
garden sandy loam soil maintained at 75% MWHC. Maximum germination was 50% achieved within a week. The
seedlings were studied when they were 20-day (younger) and 50-day old (elder). The seedling was of Phanerocotylar –
Epigeal Reserve type. The major allocation of biomass in 20-day seedlings was in leaves and in 50-day seedlings in
leaves and hypocotylar stem. The major growth spur in seedlings during the 30-day period from 20th to 50th day was in
hypocotylar and epicotylar stem and root. Tap root had profuse laterals. Numerous root nodules 3.5 - 5mm in diameter
were present generally on the main root. Cotyledons were large, green fleshy –food laden, concave inside and convex
outside with no visible venation. They were wholly consumed within 50 days after germination. Internode size reduced
from base to apex regularly. The hypocotyl was green, shining and provided with little prickles. Epicotyl is hairy. The
primary leaves were simple opposite, erect, glaucous dorsally and pubescent ventrally. The subsequent leaves were
pinnately trifoliate (ternate) with three leaflets. Each leaf had small, green and linear-lanceolate stipules. Glanduliform
stiples present. Epicotyl was longer than hypocotyl. The total leaf area of elder seedlings was (209.08 ± 15.71 cm2) -1.6
times to that in the younger seedlings. The leaf venation was pinnate camptodromous (festooned brachidodromous)
type. Vein-endings were straight or curved and unbranched. Two types of trichomes were seen – branched trichomes
and capitate glandular trichomes. The leaves were hypo-amphistomatic – paucistomatic dorsally and multistomatic
ventrally. The cotyledonary stomata were of paracytic type but on ventral surface of leaf five types of stomata (sensu
Prabhakar, 2004) - paracytic, anisocytic, anisotricytic, anomocytic and staurocytic were present; paracytic being the
most abundant and staurocytic the least. Stomata on dorsal side of leaf were rare and of paracytic type only along the
main vein. Both surfaces of leaf had capitate glandular trichomes (6.16 per mm2 on ventral surface and much infrequent
on the dorsal side). The number of stomata on ventral surface of the leaf tended to be normally-distributed amongst the
100 sampling fields of the microscope vision (each of 0.10174 mm2) at 45 x 10 X magnification. The mean density of
stomata per mm2 was 110.28 ± 2.07 (68.80 – 157.3; CV: 18.73%).