Determination of resource mobilization during seedling growth of palmyra palm, Borassus flabellifer L

Asian palmyra palm (Borassus flabellifer L.) is a multipurpose tree with year round products as food for the dependent society. Besides edible items the tree offers around 801 useful goods which are economically important. Such a plant’s seedling biology has not been fully understood. Hence, the present study was aimed at understanding seedling developmental stages and resource mobilisation in Palmyra palm and further to determine the role of cotyledonary sheath (CS) during entire seedling growth. We investigated the developmental changes throughout growth of seedlings by providing different sets of growth conditions. Artificial seed bed made of coconut coir was compared with that of soil conditions to study germination and establishment of seedlings. Phloem loading dye was used to track the flow of nutrients from embryo to cotyledonary sheath. Seed germination in palmyra palm is hypogeal by forming ligular and tubular structures remotely in soil. Eight new organs differentiate from the seed embryo that includes haustorium, ligule, cotyledonary sheath, cataphyll, eophyll, mesocotyle (junction), primary root and mesocotyl roots during seed germination. Among these the first four are temporary organs and they disintegrate once the seedling is well established. The last four organs are responsible for developing acomplete plantlet at later stages. The seed and seedling organs of Palmyra palm have four major storage reserves to support successful germination and firm establishment of seedling. Palmyra has evolved to control the solubilisation, movement and regulation of food among transient seedling organs and carry out translocation of food to the developing and differentiating organs. Seedlings also have developed physiological functions and strategies to mobilise the stored food without losing them at any point of their growth and developmental stages. Water required for seed germination permeates laterally only viacotyledonary sheath which has spongy tissues and lenticels all over. These tissues are the primary mode of water supply as the seedlings lack major root organs in the early stages of development. Flourescent microscopic and anatomical studies were carried out to observe the transport and storage of food substances required during seedling growth. Histochemical studies of seedling organs have revealed the presence of various type of nutrients such as simple sugars, carbohydrates, proteins, amino acids and lipids.

Post-seminal structure and development of the hemiparasitic plant Escobedia grandiflora (Orobanchaceae)

Escobedia grandiflora(L.f.) Kuntze is a wild hemiparasitic plant with orange roots. Little is known about the development of initial parasitism with the host, despite the significant value of roots for Central and South American communities. Therefore, this study aimed to characterize post-seminal structure and development of E. grandiflorain Pennisetum purpureumhost. To analyze the structure and development of E. grandiflora, seedlings, stems and roots samples were processed and examined underlight, confocal and scanning electron microscopy. Escobedia grandifloraseeds are composed of seed coat, perisperm, and embryo. Emergence of the radicle began eleven days after imbibition. Seedlings showed a root hair collar encircling the axis at the root-hypocotyl junction with elongation of internal cortical cells. Seedlings formed haustoria and successfully reached of the host roots 22 days following root emergence. In the root many starch grains were observed, albeit more scarce in the hypocotyl. After 43 days of root emergence, the seedling stage was finished with the formation of the definitive leaves, and star of the plant stage. After 64 days, root ramification, amount of starch, and orange pigmentation increased with formation of haustoria. The developmental pattern of E. grandiflora plants was slow, but the roots grew faster than the stem. Escobedia grandifloraseeds were not endospermic and have limited nutritional value. After root emergence, the young seedling must develop roots and starch storage towards to haustorium formation and attachment to host roots.

Morphology of seed germination and haustorium formation in Cistanche deserticola / 中草药

Object The process of seed germination and haustorium formation in Cistanche deserticola Y C Ma was observed Methods Seeds were inoculated on culture medium, the process of seed germination and haustorium formation were observed using light and electron microscopy Results The seedling sprouted after two weeks, then a tube like organ formed, finally the apex expanded to attachment organ The outer papillar surface of the extended apex bears wall protuberances that are encircled with a thick cuticular belt and covered with a thin cuticle Conclusion The seed germination of C deserticola is single pole of racidle The attachment organ adheres host first