Schools across state won’t reopen before Diwali: Maharashtra Govt. Mumbai: With Covid-19 positive cases showing no signs of slowing down in Maharashtra, the state government has decided to allow schools to reopen only after Diwali. This means children in over 1.2 lakh schools won’t be able to attend classes in person till November. Minister of School Education Varsha Gaikwad said the decision was taken after a meeting between her department and several school managements. Since schools are not ready to risk the lives of their students, the state has planned to push the reopening after Diwali, she said. Gaikwad said the Centre had sought the state government’s views about the resuming classes in schools for senior students. She said the Centre had also issued standard operating procedures or SOPs for the partial resumption of teaching activities in schools for students of Classes 9 to 12, on a voluntary basis, from September 21. Advertisement Advertisement “However, school managem...
1. Reproduction in lower and higher plants.
Part 5
Dormancy :
Structural and physiological adaptive mechanism for survival is called Dormancy.
Apomixis :
- Phenomenon of formation of embryo through asexual methods.
- Gametophytic cell produces embryo without fertilization is called Apogamy.
- Sporophytic cell produces embryo without fertilization is called Apospory.
- Apomixis is divided into three parts :
a) Recurrent Apomixis.
b) Non-recurrent Apomixis.
c) Adventive Embryony.
A) Recurrent Apomixis : The embryo sac generally rise either from an archesporial cell or form some other part of the nuclleus.
B) Non-recurrent Apomixis : Megaspore mother cell undergoes usual meiotic division and a haploid embryo sac is formed.
C) Adventive Embryony : Embryos may develop from somatic nucellus or integuments along with normal zygotic embryo.
Parthenocarpy :
- This term is coined by Noll (1902).
- The condition in which fruit is developed without the process of fertilization.
- Occur naturally in some varieties of pineapple, Banana, etc.
- The fruit resembles the normally produced fruit but it is seedless.
Polyembryony :
- The development of more than one embryos, inside the seed and the condition is described as polyembryony.
- First noticed by Leeuwenhoek in the seeds of Citrus genus.
- The additional embryos result from the differentiation and development of various maternal and zygotic tissue associated with the ovule of seed.
- Polyembryony may be true or false.
- Depending upon whether may embryos arise in the same embryo sac or in different embryo sacs in the ovule.
- Each unit then develops into an embryo.
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