Effect of number and timing of pinching on reproductive growth of potted poinsettia (Euphorbia pulcherrima Willd.)

An experiment to evaluate effects of pinching number (unpinched, once-and twice-pinched) and timing (early- and late-pinched) on reproductive growth of poinsettia was conducted. The results showed that late-pinched plants were delayed in floral induction, bract colour development and finish date compared to early-pinched plants. However, the time of pinching did not significantly affect the number of bracts and bract area, once- and twice-pinched treatment delayed floral induction, bract colour development and finish dates compared to unpinched plants. The number of bracts and bract area were increased after the plants had been pinched once or twice

Floral biology, flowering behaviour and fruit set development of Jatropha curcas L. in Malaysia

This paper describes the flowering behaviour of Jatropha curcas cultivated under Malaysian tropical climate. Investigation was carried out by observing the floral morphology, flowering sequence of pistillates, floral anthesis time, flower daily anthesis, flowering and fruiting plant behaviour, flower sex and fruit set ratio. Floral reproductive organs were examined using Scanning Electron Microscope (SEM). Jatropha is monoecious and it produces individual flowers in a dichasial cyme. Each Jatropha inflorescence has at least six compound cymes. The male flower anthesis started the earliest at 12.00 am and once again at 6.10 am to 6.46 am. The female flower anthesis commenced at 6.35 am to 8.25 am. The male flowers opened for a period of 8 to 11 days, while the female flowers opened for only 3 to 4 days. The reading of the male to the female flower ratio was taken twice, 22:1 in December 2008 and 27:1 in April 2009. The flower to fruit ratios were 6:5 (January 2009) and 2:1 (May 2009). Numerically, 0-10 female flowers and 25-215 male flowers are produced in the same inflorescence. In this study, the terminal stem of Jatropha bore fruits profusely in January, May and August 2009. Meanwhile, the development of the floral meristem consists of three stages which include a vegetative stage, a transition from vegetative to floral stage and development of flower parts. The meristem was in the transition stage at day 6. Although all sepals and a petal were developed at day 18, the presence of reproductive organs developing at this particular stage was not detected. Flower and fruit development took approximately 3 months to complete the full cycle, i.e. from the initiated floral bud stage until fruit maturity

Huanglongbing detection, gene sequencing and cell wall thickness modification in infected Citrus reticulata after chemical treatments.

Huanglongbing (HLB), also known as the citrus greening disease, is a destructive disease that has affected citrus plants in more than 40 countries worldwide. HLB is very difficult to control when the vector is spread in the citriculture areas. As presently there is no effective treatment for the citrus plants infected by the HLB disease, this study investigates chemical treatments using GA3, an antibiotic (Oxi-tetracycline), a foliar fertilizer and a combination of these chemicals to stimulate resistance to HLB in citrus plants. It employs a RCBD design with three replications. Aqueous solutions of the treatments were prepared and sprayed on whole trees and a small dose of antibiotic was injected into the trunks of the trees. Conventional PCR was not able to detect HLB bacteria in T7 but it was detected in all treatments using second conventional PCR. A comparison of the mean thickness of treated plants showed that thick cell walls were found in T4 and T7. A new strain of HLB was identified and registered in the NCBI gene bank database (GU133055) from Terengganu

Identification of ethnomedicinally important Kaempferia L. (Zingiberaceae) species based on morphological traits and suitable DNA region

Nuclear ribosomal internal transcribed spacer (ITS) sequences and morphological characteristics were used to identify medicinally important Kaempferia species cultivated in Peninsular Malaysia. Six species were evaluated for parameters such as nucleotide diversity (0.458) and estimated values of transition/transversion bias (0.89) using sequence data. Maximum parsimony (MP) analysis inferred divergence pattern in the Kaempferia genus. The resulting phylogenetic tree was compared to one formed using morphological traits. Morphological and molecular data both show 3 distinctive groupings within selected Kaempferia species. ITS 4 and 5 sequences are proposed as DNA barcodes for identification of Kaempferia species. In terms of morphological traits, plant habit, rhizome colour and leaf variation can be used for preliminary identification of this genus

Identification of physical and biochemical characteristic of mandarin (Citrus reticulata) fruit infected by Huanglongbing (HLB).

This study was conducted on an infected 8 year old Citrus reticulata orchard in Terengganu, Malaysia. Huanglongbing (HLB) was successfully detected using conventional PCR in samples with blotchy mottling and midrib yellowing symptoms. Different treatments of antibiotic (Oxi-tetracycline), GA3 and foliar fertilizer were tested on the HLB-infected citrus plants. The chemical treatments were applied before flowering (February 2008) and during fruit set (June 2008). Changes in fruit quantity and quality parameters of Citrus reticulata were studied after harvesting. Low titratable acidity (TA) was measured on T7, T6 and a high rate of TA was achieved on T8 as control. High SSC percentage was recorded in T7 followed by T2 and T8. A high peel thickness percentage, fruit weight, was recorded on T7 and T2 while low values were observed on T8 and T5. High juice percentage was recorded on T2 followed by T7 and low juice percentage was recorded on control (T8). High pulp percentage was observed on T2 followed by T7 and a low rate was measured on T8.Finally, the best treatments were T7 and T4 to increase the HLB-infected fruit quantity and quality

Seed traits and germination behaviour of kemunting (Rhodomyrtus tomentosa) populations as affected by different temperatures

To examine the variation in seed morphometric traits as well as germination performance at a range of temperatures (10-40°C), Rhodomyrtus tomentosa seeds were collected from four locations across Peninsular Malaysia (designated (C-02), (K-03), (M-01) and (T-01)). Seed source had a significant effect on seed morphometric traits with seeds from K-03 recording the highest values and seeds from C-02 the lowest values for seed length, seed width, seed thickness and 1000 seed weight. These differences in seed traits, which were attributed to maternal or environmental effects, influenced the rate of water uptake leading to variation in germination behaviour such as germination percentage (GP), days to first germination (GD) and time to 50% germination (T50) of the seeds from the four locations. Temperature significantly affected GP, GD and T50 but the effect of location was only significant for GD and T50. There were significant interaction effects of location × temperature for all the parameters tested. Generally, R. tomentosa seeds showed a slow increase in water uptake due to the presence of the operculum and the mesotesta which consists of sclerified cells, and had erratic germination behaviour

A new Vanilla species from Peninsular Malaysia

A new species, Vanilla sanguineovenosa R. Go & A. Raffi, from Peninsular Malaysia is described, illustrated, and other aspects of interest discussed. It is so far known from a small population in lower montane forests at Tapah, Perak. A field key to the Peninsular Malaysian taxa, including V. sumatrana is also provided

Ultrastructures of Candidatus Liberibacter asiaticus and its damage in huanglongbing (HLB) infected citrus

Candidatus Liberibacter asiaticus is not cultured in media and there is insufficient information on the movement of the pathogen in citrus plants. Samples were collected from infected citrus plants grown in Ulu Pakar, Terengganu, Malaysia and they show typical symptoms of the huanglongbing (HLB) disease. Polymerase chain reaction (PCR) using specific primer pairs of OI1 and OI2c was conducted to assess the presence and to amplify the Candidatus Liberibacter asiaticus in infected plants. The samples were then examined under transmission electron microscope for the determination and identification of Candidatus Liberibacter asiaticus. The spherical and rod shaped particles of this agent were found in phloem cells. The length of the bacteria ranged from 594.57 to 1368.16 nm (mean 930.09 nm) and its width ranged from 201.68 to 811.15 nm (mean 410.61nm). Cell wall membranes were irregular in shape and were of different thickness. Damage was caused by Candidatus Liberibacter asiaticus penetrating through the cell wall and their movement between cells. This study was conducted to confirm the presence of Candidatus Liberibacter asiaticus pathogen in citrus plant using transmission electron microscopy (TEM) and to identify the cell wall modifications of the phloem.Keywords: Citrus greening disease, huanglongbing, transmission electron microscopeAfrican Journal of Biotechnology Vol. 9(36), pp. 5897-5901, 6 September, 201

An efficient in vitro plantlet regeneration from shoot tip cultures of Curculigo latifolia, a medicinal plant

A procedure was developed for in vitro propagation of Curculigo latifolia through shoot tip culture. Direct regeneration and indirect scalp induction of Curculigo latifolia were obtained from shoot tip grown on MS medium supplemented with different concentrations and combinations of thidiazuron and indole-3-butyric acid. Maximum response for direct regeneration in terms of percentage of explants producing shoot, shoot number, and shoot length was obtained on MS medium supplemented with combination of thidiazuron (0.5 mg L−1) and indole-3-butyric acid (0.25 mg L−1) after both 10 and 14 weeks of cultures. Indole-3-butyric acid in combination with thidiazuron exhibited a synergistic effect on shoot regeneration. The shoot tips were able to induce maximum scalp from basal end of explants on the medium with 2 mg L−1 thidiazuron. Cultures showed that shoot number, shoot length, and scalp size increased significantly after 14 weeks of culture. Transferring of the shoots onto the MS medium devoid of growth regulators resulted in the highest percentage of root induction and longer roots, while medium supplemented with 0.25 mg L−1 IBA produced more numbers of roots